Investigating on Windows Event ID 4625 (an Account Failed to Log On)
Introduction
Windows Event ID 4625 is a critical event log that tracks failed logon attempts within a Windows environment. It is essential for security monitoring, as it provides SOC analysts with visibility into unauthorized access attempts, brute-force attacks, and other credential-based threats. This event is logged whenever a user or system attempts to log in but fails, making it a key indicator of potential malicious activity, such as attempts to steal credentials or perform lateral movement.
Event ID 4625 helps organizations monitor user behavior, identify anomalies, and respond proactively to attacks. Failed logon events can result from a variety of causes, including incorrect passwords, disabled accounts, or expired credentials. However, they can also signal the beginning of more dangerous attacks, such as brute-force login attempts, credential stuffing, or exploitation of weak authentication methods.
In this article, we will explore the significance of Event ID 4625 in a security context, providing SOC analysts with the knowledge and tools necessary to investigate and respond to failed logon attempts. We will also cover common attack scenarios, methods to analyze failed logons, and best practices for strengthening your organization’s authentication defenses.
Objectives
The primary objective of this article is to equip SOC analysts and security professionals with the knowledge and tools required to effectively monitor, analyze, and investigate Windows Event ID 4625 — a critical log event that tracks failed logon attempts. Understanding and responding to these events is essential for detecting unauthorized access attempts, preventing credential theft, and mitigating potential cyberattacks.
This article will focus on the following key objectives
By the end of this article, SOC analysts will have a clear understanding of how to monitor failed logon attempts, investigate potential threats, and implement security measures to reduce the risk of credential-based attacks and unauthorized access.
Why Windows Event ID 4625 Matters for Security Monitoring
Windows Event ID 4625 is one of the most important events for detecting failed logon attempts in a Windows environment. This event is logged whenever a user or system attempts to log in but fails, making it a key indicator of potential unauthorized access attempts, credential-based attacks, and misconfigurations. By monitoring and investigating Event ID 4625, SOC analysts can gain early visibility into security threats that could otherwise go undetected.
Early Detection of Credential-Based Attacks
Event ID 4625 is often the first sign of malicious activity in an organization. Attackers frequently attempt to gain unauthorized access by brute-forcing passwords or using stolen credentials, resulting in multiple failed logon attempts before they succeed.
Monitoring failed logons is critical for detecting the following types of attacks
By identifying these patterns, SOC analysts can act quickly to block further logon attempts, lock down compromised accounts, or strengthen access controls to prevent unauthorized access.
Defense Against Insider Threats
Not all failed logon attempts are the result of external attackers. Insider threats, including disgruntled employees or users attempting to escalate privileges, can generate Event ID 4625 as they try to access systems for which they do not have the correct credentials. Monitoring failed logon attempts allows organizations to identify:
Identifying Misconfigurations and System Issues
Not all failed logon attempts are malicious. Event ID 4625 can also help identify system misconfigurations or account-related issues that could lead to legitimate users being locked out of their accounts or denied access to important systems.
Some common reasons for failed logons include
By tracking these failed logon attempts, SOC analysts can proactively resolve misconfigurations, reduce the risk of user frustration, and ensure that the organization's authentication systems are working properly.
Correlation with Other Events for Threat Detection
To maximize the value of Event ID 4625, SOC analysts should correlate failed logon events with other critical event IDs to detect more complex attack scenarios.
For example
Strengthening Security Incident Response and Mitigation
Monitoring Event ID 4625 helps organizations implement timely security incident response strategies. When failed logon attempts are detected, organizations can take the following actions to mitigate potential threats:
By understanding why Windows Event ID 4625 matters for security monitoring, SOC analysts can improve their organization’s detection and response capabilities, ensuring early identification of threats and better protection against unauthorized access.
Understanding Windows Event ID 4625
Windows Event ID 4625 is logged every time a failed logon attempt occurs on a system running the Windows operating system. This event provides detailed information about the reason for the failure, the account involved, the source of the attempt, and the authentication process. By understanding the key components of this event and the conditions under which it is triggered, SOC analysts can gain critical insights into potential security incidents.
When is Event ID 4625 Triggered?
Event ID 4625 is generated when a user or system attempts to log in to a Windows machine but fails. Failed logons can occur for a variety of reasons, ranging from user error (e.g., typing the wrong password) to more malicious actions, such as brute-force or credential-stuffing attacks.
Common scenarios that trigger Event ID 4625 include
Key Data Fields in Event ID 4625
Understanding the critical data fields in Event ID 4625 is essential for effective analysis. Each field contains important information that helps SOC analysts investigate the cause of the failed logon and determine whether it is part of a broader security threat.
Key data fields include
-- Type 2: Interactive Logon – A failed attempt to log in locally (physically at the machine).
-- Type 3: Network Logon – A failed attempt to access the machine via a network (e.g., file sharing, remote logons).
-- Type 4: Batch Logon – A failed logon attempt for a batch-processed job, typically used for scheduled tasks.
-- Type 5: Service Logon – A failed attempt made by a service to log in.
-- Type 7: Unlock – A failed attempt to unlock a workstation.
-- Type 8: NetworkCleartext Logon – A failed logon where credentials are sent in plaintext over the network.
-- Type 9: NewCredentials – A failed attempt where new credentials are used without reusing an existing session.
-- Type 10: RemoteInteractive Logon – A failed logon attempt via Remote Desktop Protocol (RDP), often linked to lateral movement.
-- Type 11: CachedInteractive Logon – A failed attempt using cached credentials, commonly used when authenticating without immediate contact to the domain controller.
-- Type 12: CachedRemoteInteractive Logon – A failed logon attempt using cached credentials for remote sessions.
-- Type 13: CachedUnlock – A failed attempt to unlock a workstation using cached credentials.
Common Logon Failure Scenarios
Event ID 4625 can be triggered by various legitimate or malicious actions. SOC analysts must understand common failure scenarios to distinguish between normal operational issues and potential security threats.
How Event ID 4625 Supports Threat Detection
Windows Event ID 4625 provides critical data points that help SOC analysts detect and investigate potential threats, especially when correlated with other events. Some ways in which Event ID 4625 supports threat detection include:
Limitations of Event ID 4625
While Event ID 4625 provides valuable information, it is important to recognize its limitations:
By understanding the key components of Windows Event ID 4625 is crucial for SOC analysts to distinguish between routine system activity and potential security threats. By examining the key data fields, failure reasons, and common logon failure scenarios, analysts can effectively investigate and respond to failed logon events.
Historical Context or Evolution of Windows Event ID 4625
Windows Event ID 4625, which logs failed logon attempts, has evolved over time, particularly in response to growing security threats and the need for more detailed auditing capabilities in enterprise environments. Understanding the historical context and evolution of this event provides SOC analysts with insights into how failed logon monitoring has improved over different Windows versions, as well as how these logs have become more critical for detecting modern cyberattacks.
Early Windows Versions and Basic Logon Auditing
In earlier Windows versions (such as Windows NT and Windows 2000), auditing capabilities for logon events were relatively limited. Failed logon attempts were logged, but the level of detail provided was minimal, often not capturing critical data points like the logon type or the specific reason for failure. This made it difficult for SOC analysts to distinguish between legitimate failed logons (e.g., a user mistyping their password) and malicious attempts (e.g., brute-force attacks or credential stuffing).
Over time, as security threats evolved, organizations began to demand more granular auditing capabilities to help detect credential-based attacks and other sophisticated techniques. Windows introduced improvements to its event logging system, culminating in the creation of detailed logon event IDs like Event ID 4625.
Windows Vista/Server 2008: The Introduction of Event ID 4625
The introduction of Windows Vista and Windows Server 2008 marked a major shift in Windows auditing. These versions introduced Event ID 4625, a comprehensive logon event specifically designed to capture failed logon attempts. This event provided significantly more detail than previous Windows logon events, capturing essential information such as:
The creation of Event ID 4625 represented a major improvement in logon auditing, enabling SOC analysts to monitor failed logon attempts with much greater precision. This improvement also helped address growing threats such as credential stuffing, brute-force attacks, and account misuse.
Windows 8/Server 2012: Enhanced Auditing for Remote Logons
With the release of Windows 8 and Windows Server 2012, Microsoft further enhanced the auditing capabilities of Event ID 4625 by adding more detailed logging for remote logons. This improvement was in response to the increasing use of Remote Desktop Protocol (RDP) in enterprise environments and the growing risk of remote attacks.
Event ID 4625 began to more clearly log failed attempts related to LogonType 10 (RemoteInteractive Logon), making it easier to identify failed RDP logons. This enhanced visibility helped SOC teams detect brute-force attacks targeting RDP services, a common method attackers use to gain access to internal systems.
Windows 10/Server 2016 and Beyond: Strengthening Kerberos and Credential Security
As Windows 10 and Windows Server 2016 were introduced, Event ID 4625 continued to evolve, with further improvements in logging capabilities around authentication methods like Kerberos and NTLM. Given the increasing prevalence of Kerberos-based attacks, such as Pass-the-Ticket and Golden Ticket, the level of detail captured in Event ID 4625 became critical for detecting and preventing these advanced threats.
Microsoft also increased auditing capabilities around failed logon attempts for service accounts and scheduled tasks, logging events like LogonType 5 (Service Logon) and LogonType 4 (Batch Logon). These improvements helped organizations monitor not just user logons, but also system-level authentication failures that could indicate misconfigurations or malicious activity.
Modern Threats and the Continued Importance of Event ID 4625
In today’s threat landscape, where credential theft and abuse are among the most common attack vectors, Event ID 4625 plays an increasingly vital role in defending against attacks. Modern attackers use techniques like phishing, credential stuffing, and brute-force attacks to steal credentials, making the ability to monitor failed logon attempts a key element of any organization's security strategy.
The detailed data provided by Event ID 4625 allows SOC analysts to
As Microsoft continues to update its operating systems, Event ID 4625 will remain a core event for security teams to detect, investigate, and respond to failed logon attempts.
By understanding the historical evolution of Event ID 4625, SOC analysts can appreciate the improvements made over time and leverage these detailed logs to enhance their organization's security posture against modern credential-based attacks.
Common Attack Scenarios Involving Windows Event ID 4625
Windows Event ID 4625 is an essential log event for detecting and investigating a wide range of security threats. It helps SOC analysts identify failed logon attempts that could indicate malicious activities such as credential-based attacks, privilege escalation attempts, and brute-force tactics. In this chapter, we will explore several common attack scenarios where Event ID 4625 plays a critical role in identifying and responding to threats.
Brute-Force Attacks
Brute-force attacks involve systematically guessing a large number of username and password combinations to gain unauthorized access. Attackers often use automated tools to perform this type of attack, generating numerous failed logon attempts as they try different credentials. Event ID 4625 logs these failed attempts, making it a key event for detecting brute-force attacks early.
Typical Signs in Event ID 4625
SOC analysts can set thresholds for detecting multiple Event ID 4625 logs over a short period, triggering alerts when suspicious patterns emerge, helping prevent successful brute-force attacks.
Credential Stuffing
Credential stuffing is an attack in which attackers use lists of username-password pairs obtained from previous data breaches to attempt logons across multiple accounts. This technique is particularly dangerous because it relies on the fact that many users reuse passwords across different services.
Typical Signs in Event ID 4625
Event ID 4625 helps identify the beginning stages of credential stuffing attacks by logging each failed attempt, allowing security teams to lock down accounts before attackers gain access.
Pass-the-Ticket Attacks
In a Pass-the-Ticket attack, attackers use stolen Kerberos tickets to authenticate to systems without needing the actual user credentials. While this attack is often associated with Event ID 4769 (Kerberos service ticket requests), failed attempts to use invalid or expired tickets can generate Event ID 4625.
Typical Signs in Event ID 4625
By correlating Event ID 4625 with Kerberos-related events (Event IDs 4768, 4769), SOC analysts can detect failed attempts to authenticate using forged tickets.
Password Spraying
Password spraying is a type of brute-force attack where attackers try a limited set of commonly used passwords (such as "password123" or "welcome") against a large number of accounts. This tactic helps attackers avoid triggering account lockout mechanisms, making detection more challenging.
Typical Signs in Event ID 4625
Password spraying attacks can often be detected by examining multiple Event ID 4625 logs across different accounts, combined with awareness of corporate password policies and commonly used passwords.
Privilege Escalation Attempts
Attackers or insiders attempting to gain unauthorized access to high-privilege accounts often generate multiple failed logon events (Event ID 4625) before they succeed. These attempts are typically aimed at gaining administrative or domain controller access.
Typical Signs in Event ID 4625
By monitoring Event ID 4625 logs for failed attempts to access privileged accounts, SOC analysts can take proactive measures to investigate potential insider threats or external privilege escalation attempts.
Remote Desktop Protocol (RDP) Attacks
Attackers frequently target systems exposed to the internet via Remote Desktop Protocol (RDP) as a way to gain unauthorized access. Event ID 4625 logs failed RDP login attempts (LogonType 10: RemoteInteractive Logon), which can indicate attempts to break into remote systems.
Typical Signs in Event ID 4625
Monitoring Event ID 4625 for RDP-related failures is essential for organizations that use remote access, as it helps detect and mitigate RDP-based attacks that target exposed servers.
Insider Threats
Not all attacks come from external sources. Insider threats—whether malicious or accidental—can result in multiple failed logon attempts. For example, an employee trying to access resources they are not authorized to use may trigger multiple Event ID 4625 logs.
Typical Signs in Event ID 4625
Event ID 4625 provides critical visibility into insider threats by tracking failed logon attempts that can be early indicators of unauthorized access attempts by employees.
It's important to understand that Event ID 4625 is a critical log event for detecting and responding to a wide range of attacks, including brute-force, credential stuffing, privilege escalation, and RDP attacks. By closely monitoring and analyzing failed logon attempts, SOC analysts can swiftly identify potential threats and take proactive steps to protect their organization from unauthorized access.
Practical Examples of Windows Event ID 4625
To fully understand the significance of Windows Event ID 4625 and its role in detecting failed logon attempts, it’s helpful to look at practical examples that show how this event is used in real-world scenarios. This chapter walks through several use cases that highlight how SOC analysts can detect, investigate, and respond to different types of threats using Event ID 4625. These examples also provide insights into the investigative process and demonstrate how Event ID 4625 can be correlated with other log events for more effective security monitoring.
Example 1
Detecting Brute-Force Attacks
Scenario
A large organization begins noticing an unusual spike in failed logon attempts across multiple user accounts. The SOC team is alerted to the increase in Event ID 4625 logs, which shows a high number of failed logons targeting specific accounts.
Steps for Analysis
Outcome
The brute-force attack is thwarted before any accounts are compromised, and the organization adjusts its security policies to mitigate future risks.
Example 2
Identifying a Credential Stuffing Attack
Scenario
The SOC team notices multiple failed logon attempts across various accounts, all logged as Event ID 4625. The attempts occur within a short time frame and target a wide range of users.
Steps for Analysis
Outcome
The SOC team disables the targeted accounts, forces password resets, and configures multi-factor authentication (MFA) for added protection, successfully preventing the credential stuffing attack.
Example 3
Investigating an Insider Privilege Escalation Attempt
Scenario
An employee attempts to access sensitive systems for which they do not have the appropriate permissions. The SOC team notices several failed logon attempts in Event ID 4625, all originating from the employee’s workstation.
Steps for Analysis
Outcome
The insider privilege escalation attempt is caught early, preventing potential data theft or system tampering. The organization conducts a follow-up investigation to address the insider threat.
Example 4
Responding to Remote Desktop Protocol (RDP) Attacks
Scenario
A company using RDP to allow employees to work remotely starts seeing multiple failed logon attempts in Event ID 4625, specifically targeting RDP access.
Steps for Analysis
Outcome
The company successfully prevents unauthorized RDP access and strengthens its remote access policies to reduce the risk of future attacks.
Example 5
Detecting a Service Account Misconfiguration
Scenario
A service account responsible for running automated tasks begins generating repeated failed logon attempts, all logged under Event ID 4625.
Steps for Analysis
Outcome
The service is restored without causing any significant disruption to business operations, and the SOC team ensures that all automated tasks use the correct credentials moving forward.
These practical examples demonstrate how Windows Event ID 4625 can be used to detect and investigate a wide range of security threats, from external brute-force attacks to internal privilege escalation attempts. By effectively analyzing failed logon attempts and correlating them with other security events, SOC analysts can identify threats early and take proactive measures to safeguard their organization from unauthorized access.
Analysis of Windows Event ID 4625
Windows Event ID 4625 logs are crucial for identifying and analyzing failed logon attempts, providing SOC analysts with detailed insights into potential security incidents. Proper analysis of these logs helps distinguish between normal user activity and signs of malicious behavior, such as brute-force attacks, credential theft, and insider threats. In this chapter, we will focus on the process of analyzing the key data fields in Event ID 4625, understanding patterns of failure, and correlating this data with other events to detect security issues.
Understanding Key Data Fields
Event ID 4625 provides a wealth of information about failed logon attempts. SOC analysts must carefully examine these fields to interpret the log data and determine the nature of the failed attempt. Below are the most critical fields for analysis:
-- Type 2 (Interactive Logon): Indicates an attempt to log in locally at the machine (e.g., physically at the console).
-- Type 3 (Network Logon): Indicates a logon attempt over a network, such as accessing shared resources or remotely connecting to services.
-- Type 4 (Batch Logon): Refers to batch-processed jobs, typically automated tasks or scheduled processes, attempting to log on.
-- Type 5 (Service Logon): Indicates a logon attempt by a service running on the system.
-- Type 7 (Unlock): This logon type represents a failed attempt to unlock a workstation.
-- Type 8 (NetworkCleartext Logon): Represents a logon where credentials are sent in plaintext over the network, which is commonly targeted in attacks involving weak security protocols.
-- Type 9 (NewCredentials): Refers to a logon where new credentials are used without needing to log off (e.g., using the RunAs command).
-- Type 10 (RemoteInteractive Logon): Points to an attempt to log in via Remote Desktop Protocol (RDP), often targeted in lateral movement or brute-force attacks.
-- Type 11 (CachedInteractive Logon): Represents a logon attempt using cached credentials when the domain controller is not available.
-- Type 12 (CachedRemoteInteractive Logon): A cached logon for remote interactive sessions, typically when offline RDP logon is attempted.
-- Type 13 (CachedUnlock): Indicates an attempt to unlock a workstation using cached credentials.
-- Unknown user name or bad password: Indicates incorrect credentials, often seen in brute-force or credential-stuffing attacks.
-- Account currently disabled: Shows that the account is no longer active, which may indicate either an internal issue or an attacker attempting to access a locked-out account.
-- Account expired: The account's expiration date has passed, preventing the logon. This could be a result of account management policies or attackers trying to use outdated credentials.
-- Account locked out: The account has been locked out due to too many failed logon attempts, usually in response to brute-force or password-spraying attacks.
-- User not allowed to logon at this computer: This failure occurs when a user is restricted from logging into specific devices, typically due to access control policies.
-- Logon hours restricted: The logon attempt is being made outside of the hours allowed for the account, indicating either a misconfiguration or potential malicious behavior.
-- Password expired: The password for the account has expired, preventing logon. While this is often an administrative issue, repeated failures may indicate that an attacker is using an account with outdated credentials.
-- No logon servers available: The system could not contact a domain controller to validate the user credentials. This may indicate network issues, but if persistent, it could also point to an attacker attempting to bypass network defenses.
-- Password change required: The user’s password must be changed before further logons are allowed. Attackers using compromised accounts may trigger this event if the password has been flagged for change.
-- 0xC000006A (Incorrect Password): The password provided is incorrect, often seen in brute-force attacks or when a user mistypes their password.
-- 0xC0000064 (User Account Doesn’t Exist): The user account does not exist, which is commonly seen in credential-stuffing attempts where attackers use outdated or invalid usernames.
-- 0xC0000070 (Account Restrictions): The account is restricted from logging on to the system, possibly due to group policies or login hour restrictions.
-- 0xC000006F (Logon Failure): This indicates a generic failure where the user is not allowed to log on at this computer, which can be due to access control restrictions.
-- 0xC000006D (Bad Credentials): The logon attempt failed because the provided credentials do not match any active account. This might be an indication of a brute-force attack or incorrect credentials.
-- 0xC0000193 (Account Expired): The user account has expired and is no longer valid for logon. This could indicate outdated credentials being used by an attacker.
-- 0xC000015B (Logon Type Not Granted): The user does not have permission to log on using the requested logon type, such as network or remote interactive logon.
-- 0xC0000071 (Password Expired): The user’s password has expired and must be changed before they can log in. Repeated failures might suggest an attacker is using outdated credentials.
-- 0xC0000224 (User Must Change Password): The user must change their password before logging in. This typically happens after administrative changes or when an account has been flagged for a password update.
-- 0xC0000192 (Attempting Logon Outside of Allowed Hours): The user attempted to log in outside of their permitted login hours, indicating either a policy issue or potential malicious activity.
-- 0xC0000234 (Account Locked Out): The account has been locked due to too many failed logon attempts, often triggered by brute-force attacks.
-- 0xC00002EE (No Logon Servers Available): This indicates that the logon attempt failed because the system could not contact a domain controller to validate the credentials.
By thoroughly examining these fields, SOC analysts can better understand the context of the failed logon and determine whether the failure is due to an operational issue, user error, or a potential attack.
Identifying Patterns and Trends
An important part of analyzing Event ID 4625 is identifying patterns and trends that can indicate the start of an attack. SOC analysts should monitor for the following red flags:
Correlating Event ID 4625 with Other Security Events
To gain a complete picture of what is happening during failed logon attempts, Event ID 4625 must be analyzed in correlation with other related log events. This correlation helps SOC analysts identify more complex attack scenarios, such as lateral movement or privilege escalation.
Analyzing Geographic and Network Activity
Another key component of analyzing Event ID 4625 is understanding the geographic location and network behavior of failed logon attempts. SOC analysts should track the SourceNetworkAddress and compare it with known user locations, VPN logs, or firewall rules.
Automating Detection with SIEM Tools
Using Security Information and Event Management (SIEM) tools can help automate the analysis of Event ID 4625 and detect patterns that would otherwise be difficult to identify manually. SOC analysts can set up custom alerts and dashboards to monitor:
Effective analysis of Windows Event ID 4625 is essential for identifying suspicious logon attempts, understanding the nature of failed authentications, and detecting early signs of attacks. By examining key data fields, identifying patterns of failure, correlating Event ID 4625 with other security logs, and leveraging automation tools like SIEM, SOC analysts can strengthen their organization’s defenses against credential-based attacks and unauthorized access.
Investigating Windows Event ID 4625
The investigation of Windows Event ID 4625, which logs failed logon attempts, is crucial for identifying security incidents such as brute-force attacks, credential stuffing, or privilege escalation attempts. Proper investigation workflows allow SOC analysts to uncover patterns, correlate failed logons with other suspicious events, and determine whether the activity is benign or malicious. This chapter outlines the investigation process for analyzing failed logon attempts and guides analysts through structured investigation techniques to respond effectively.
Establishing Context and Baselines
Before diving into a detailed investigation, it's essential to establish a baseline of normal logon activity. Anomalies such as an unusually high number of failed logon attempts or logons occurring outside typical work hours should raise immediate red flags.
Steps for Establishing Context:
Investigative Steps Based on Logon Type
The LogonType field in Event ID 4625 provides insight into how the logon attempt was initiated, which directs the focus of the investigation.
Common Logon Types and Investigative Actions:
Correlating with Other Event Logs
To paint a complete picture of the activity, failed logons (Event ID 4625) should be correlated with other event logs to identify patterns of malicious behavior. This multi-layered approach helps uncover hidden attack vectors and provides a deeper understanding of the security incident.
Key Events for Correlation:
Analyzing Failure Reasons and SubStatus Codes
Event ID 4625 provides detailed failure reasons and SubStatus codes, which help analysts understand the cause of the logon failure and direct their investigation accordingly.
Investigative Actions Based on Failure Reasons:
Tracking Failed Logons Across Multiple Accounts
An investigation should include analyzing whether failed logon attempts are focused on a single account or multiple accounts across the system.
Advanced Investigation Using Threat Intelligence
Leveraging threat intelligence platforms (TIPs) can enhance investigations by correlating failed logons with known malicious IP addresses, domains, or patterns of attack.
Steps for Integrating Threat Intelligence
Determining Malicious Intent
Ultimately, the goal of the investigation is to determine whether the failed logon attempts were malicious or benign. If malicious intent is suspected, immediate actions should be taken to contain the threat.
Steps for Confirming Malicious Intent
Investigating Windows Event ID 4625 is critical for detecting unauthorized access attempts and identifying potential security incidents. By following a structured investigation process—establishing baselines, analyzing logon types, correlating with other event logs, and leveraging threat intelligence—SOC analysts can efficiently determine the root cause of failed logons and take the necessary steps to contain potential threats.
Response Strategies for Windows Event ID 4625
Responding effectively to failed logon attempts logged by Windows Event ID 4625 is crucial to preventing unauthorized access and mitigating the risk of credential-based attacks. When multiple failed logon attempts are detected, SOC analysts need to implement immediate containment measures, investigate the security incident thoroughly, and deploy long-term security enhancements to safeguard against future threats. This chapter outlines response strategies for handling failed logons, focusing on immediate actions, security improvements, and proactive monitoring to reduce the risk of successful compromises.
Immediate Response Actions
When multiple failed logon attempts are detected, the first priority is containment to minimize the risk of unauthorized access. These immediate actions are designed to stop ongoing attacks and prevent further exploitation of compromised accounts or credentials.
Key Immediate Response Actions
Short-Term Security Incident Containment and Investigation
Once the immediate response actions are in place, it's important to conduct a short-term investigation to determine the scope of the security incident and assess potential risks. This investigation is aimed at understanding whether the failed logon attempts were part of an isolated security incident or a broader attack.
Key Containment and Investigation Steps
Long-Term Mitigation Strategies
After addressing the immediate threat and investigating the scope of the security incident, organizations must implement long-term security measures to prevent future security incidents. These strategies focus on improving authentication processes, strengthening account security, and hardening defenses against credential-based attacks.
Key Long-Term Mitigation Strategies
-- Limiting RDP access to specific IP addresses or VPN connections.
-- Requiring MFA for all remote access.
-- Enforcing encrypted communication channels and reducing RDP exposure to the internet.
Ongoing Monitoring and Proactive Measures
Ongoing monitoring of failed logon attempts is key to detecting and preventing future attacks. By proactively monitoring logon activity, SOC teams can spot early warning signs of credential abuse and take action before an attacker can succeed.
Key Proactive Measures
-- Multiple failed logon attempts within a short time period.
-- Failed logons followed by successful logons for the same account.
-- Failed logons originating from unusual geographic locations or IP addresses.
Documentation and Post-Incident Review
After the security incident has been contained and mitigated, it’s important to document the response process and conduct a post-incident review. This helps identify gaps in the response process, improve future security incident handling, and ensure that lessons learned are integrated into the organization’s security strategy.
Key Post-Incident Actions
Responding to failed logon attempts logged by Windows Event ID 4625 requires a coordinated strategy that includes immediate containment actions, thorough investigation, and long-term security enhancements. By implementing strong authentication measures, proactively monitoring logon activity, and conducting thorough post-incident reviews, SOC analysts can strengthen their organization’s defenses and reduce the likelihood of future credential-based attacks.
Best Practices for Handling Windows Event ID 4625
To effectively handle and mitigate the risks associated with failed logon attempts logged by Windows Event ID 4625, organizations need to implement a set of best practices that focus on both detection and prevention. These practices help ensure that failed logons are properly monitored, analyzed, and addressed in a way that improves overall security and reduces the risk of credential-based attacks, unauthorized access, and system compromise. In this chapter, we outline key best practices that SOC teams and IT administrators should follow to strengthen their defenses.
Enforce Multi-Factor Authentication (MFA)
One of the most effective defenses against credential-based attacks is enforcing multi-factor authentication (MFA). MFA adds an additional layer of security by requiring users to provide a second form of authentication (e.g., a one-time code sent to a mobile device) in addition to their password.
Best Practice
Strengthen Password Policies
Weak or reused passwords are often the root cause of successful brute-force attacks and credential stuffing. Strengthening password policies is crucial to protecting user accounts from unauthorized access.
Best Practice
Monitor Failed Logon Attempts in Real-Time
Real-time monitoring of failed logon attempts is essential to catching credential-based attacks in their early stages. This proactive monitoring enables SOC analysts to detect patterns of suspicious logon behavior and respond before an attacker can successfully log in.
Best Practice
Implement Account Lockout Policies
Account lockout policies help prevent attackers from successfully using brute-force attacks to guess user passwords. By locking the account after a certain number of failed attempts, you limit the window of opportunity for attackers.
Best Practice
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Limit Remote Access and Secure RDP
Remote access, especially via RDP, is a common attack vector for threat actors attempting to gain access to systems. Limiting and securing remote access is critical to reducing the risk of failed logon attempts turning into successful compromises.
Best Practice
Review and Harden Service Accounts
Service accounts are often overlooked in security policies, yet they can be a significant target for attackers. Ensuring that service accounts are properly managed and secured reduces the likelihood of failed logon attempts.
Best Practice
Audit and Patch Vulnerabilities Regularly
Vulnerabilities in authentication systems or protocols, such as unpatched RDP services or weak encryption configurations, are often exploited by attackers to conduct brute-force or credential-based attacks.
Best Practice
Conduct Regular Security Awareness Training
User behavior is often the weakest link in security, and failed logon attempts can often be traced back to human error or poor security practices. Regular security awareness training can help reduce the risk of user-generated vulnerabilities.
Best Practice
Implementing these best practices helps SOC teams and IT administrators better monitor and manage failed logon attempts logged by Event ID 4625. By enforcing strong password policies, limiting remote access, securing service accounts, and leveraging real-time monitoring, organizations can significantly reduce the risk of credential-based attacks and unauthorized access.
Custom Security Policy Recommendations for Windows Event ID 4625
Windows Event ID 4625 provides a valuable audit trail for failed logon attempts, helping organizations detect and respond to potential security incidents such as brute-force attacks, credential stuffing, and unauthorized access attempts. To enhance detection and monitoring capabilities, it is essential to implement custom security policies tailored to your organization’s environment. These policies help ensure that failed logon attempts are logged effectively and that alerts are triggered for suspicious activity, minimizing the risk of a successful attack.
In this chapter, we will explore custom security policy recommendations for improving detection, logging, and overall security posture with respect to Windows Event ID 4625.
Configuring Audit Policies for Logon Events
Effective auditing policies are the foundation for capturing and monitoring failed logon attempts. By configuring custom audit policies, organizations can ensure that all failed and successful logons are properly recorded, allowing for thorough analysis and security incident detection.
Recommended Audit Settings
-- Enable Failure auditing to capture all failed logons.
Tuning Event Log Settings
Adjusting the Windows event log settings ensures that logs are retained for long enough periods and that critical log data is not overwritten due to insufficient log storage.
Recommended Event Log Configurations:
-- Recommended Size: Start with 1GB, depending on the volume of logs generated.
Lockout and Password Policies
Implementing well-defined lockout and password policies is critical for mitigating the risk of brute-force attacks and ensuring that attackers cannot abuse weak passwords to gain unauthorized access.
Recommended Lockout and Password Policy Settings
Restricting and Securing Remote Access
Given that many attacks target remote access protocols, such as Remote Desktop Protocol (RDP), securing and restricting remote access is a key part of defending against unauthorized logon attempts.
Recommended Remote Access Security Policies
Service Account and Privileged Account Policies
Service accounts and privileged accounts are high-value targets for attackers. These accounts require additional protection to prevent exploitation through credential-based attacks.
Recommended Service and Privileged Account Policies
Custom SIEM Rules and Alerts
Custom SIEM rules can help automate the detection and response to suspicious failed logon activity by triggering alerts based on predefined conditions.
Recommended SIEM Rules
Custom security policies are critical to effectively handling failed logon attempts logged by Windows Event ID 4625. By configuring robust audit policies, enhancing log retention settings, securing remote access, and applying strong authentication measures, organizations can significantly reduce the risk of unauthorized access and improve their ability to detect and respond to credential-based attacks.
Mapping to Threat Models (MITRE ATT&CK, Cyber Kill Chain)
Windows Event ID 4625 plays a crucial role in detecting failed logon attempts that could be indicators of various cyberattack techniques. By mapping these failed logons to established threat models, such as MITRE ATT&CK and the Cyber Kill Chain, SOC analysts can gain deeper insights into the adversarial behavior, understand how failed logon attempts fit into the broader attack lifecycle, and apply appropriate response strategies.
In this chapter, we will explore how Windows Event ID 4625 aligns with different phases of these threat models and how it helps detect specific attack techniques commonly used by adversaries.
Mapping to the MITRE ATT&CK Framework
The MITRE ATT&CK framework is a comprehensive knowledge base of adversarial tactics and techniques observed in the real world. Windows Event ID 4625 is commonly seen in several techniques associated with credential access, lateral movement, and defense evasion. Below are some key tactics and techniques from MITRE ATT&CK where Event ID 4625 plays a significant role:
Credential Access (Tactic ID: TA0006)
Credential access involves techniques that adversaries use to steal user credentials, allowing them to gain unauthorized access to systems.
Detection Strategy: Monitor failed logon attempts for patterns indicative of brute-force attacks, such as multiple failed logons in rapid succession, especially for privileged accounts or high-value targets.
Detection Strategy: Set up alerts for repeated failed logons targeting multiple accounts from the same IP address, which could indicate credential stuffing using previously compromised credentials.
Lateral Movement (Tactic ID: TA0008)
Lateral movement refers to techniques that attackers use to move from one system to another within a network after gaining initial access.
Detection Strategy: Correlate failed Kerberos logons (Event IDs 4625 and 4768) with other indicators of compromised tickets, such as abnormal Ticket Granting Ticket (TGT) requests, to detect Pass-the-Ticket activity.
Defense Evasion (Tactic ID: TA0005)
Defense evasion involves techniques adversaries use to avoid detection, disable security mechanisms, or hide their activities.
Detection Strategy: Monitor failed logon attempts that specifically target disabled or locked accounts, as these could indicate attackers probing for inactive accounts with residual access.
Privilege Escalation (Tactic ID: TA0004)
Privilege escalation refers to techniques that attackers use to gain higher-level access, such as administrative or domain-level access.
Detection Strategy: Correlate failed logons on privileged accounts with attempts to assign special privileges (Event ID 4672) to identify failed privilege escalation attempts.
Mapping to the Cyber Kill Chain
The Cyber Kill Chain is a security framework that describes the different stages of a cyberattack, from initial reconnaissance to the attacker achieving their objectives. Windows Event ID 4625 is relevant in multiple stages of the Cyber Kill Chain, particularly in the Delivery, Exploitation, and Actions on Objectives phases.
Delivery (Phase 3)
The delivery phase involves adversaries attempting to deliver malicious code or gain access to a target system. Failed logon attempts logged by Event ID 4625 can indicate attackers attempting to deliver or establish access by using brute-force or credential stuffing attacks.
Response: Implement strong password policies and MFA to prevent credential-based attacks and monitor failed logon attempts to detect and respond to delivery-stage attacks early.
Exploitation (Phase 4)
Exploitation involves attackers leveraging vulnerabilities or weaknesses in the system to gain control. Failed logon attempts targeting privileged accounts or administrative services (such as RDP) can signal exploitation attempts.
Response: Correlate failed logons with vulnerability scans and privilege assignment logs (Event ID 4672) to investigate potential exploitation activities.
Actions on Objectives (Phase 7)
In this phase, attackers attempt to achieve their final goals, such as data exfiltration or system manipulation. Event ID 4625 logs failed logon attempts to high-value accounts that attackers need to access sensitive data or execute their objectives.
Response: Implement real-time monitoring and set up alerts for failed logons on high-value accounts to catch potential breaches before attackers achieve their goals.
Understanding the Big Picture with Threat Models
While individual failed logon attempts (Event ID 4625) are important, it is crucial to consider them as part of the larger attack context. Adversaries often use multiple tactics and techniques over time, and correlating failed logons with other security events is critical for understanding the full scope of the attack.
Best Practices for Leveraging Threat Models
Mapping Windows Event ID 4625 to established threat models like MITRE ATT&CK and the Cyber Kill Chain helps SOC analysts understand where failed logon attempts fit into larger attack patterns. By doing so, organizations can enhance their detection, investigation, and response capabilities, enabling them to catch adversaries early and reduce the risk of a successful attack.
Known False Positives/Negatives for Windows Event ID 4625
When analyzing failed logon attempts captured by Windows Event ID 4625, it is important to recognize that not all failed logons represent malicious activity. In some cases, legitimate users or system processes can trigger failed logon attempts, leading to false positives. Conversely, false negatives—where malicious activity goes unnoticed—can occur if logon failures are improperly filtered out or missed during analysis. Understanding these scenarios helps SOC analysts fine-tune their monitoring efforts and avoid alert fatigue while ensuring that genuine threats are detected and responded to.
In this chapter, we will explore common sources of false positives and negatives for Windows Event ID 4625 and provide recommendations on how to minimize both.
Common False Positives
False positives occur when legitimate activity triggers failed logon events, leading to unnecessary alerts or investigations. SOC teams need to differentiate between benign activity and actual threats to avoid wasting time and resources on non-malicious events.
Incorrect Password Entries by Legitimate Users
One of the most common sources of false positives is when legitimate users simply mistype their passwords or forget them. In environments where strict account lockout policies are in place, users may trigger multiple failed logons before successfully authenticating.
Recommendation: While this can result in many alerts, SOC analysts should balance detection thresholds to avoid over-alerting on minor user errors. Establish thresholds that allow for a reasonable number of failed attempts before triggering alerts. Additionally, reviewing logon types (e.g., LogonType 2 for interactive logons) can help distinguish between local user errors and more suspicious network-based logon attempts.
Expired Passwords
Failed logon attempts due to expired passwords, especially for service accounts or users unaware that their password needs updating, can also generate false positives.
Recommendation: Regularly monitor and manage password expiration policies, especially for service accounts, to reduce the likelihood of triggering false positives. Ensure that users are notified of upcoming password expirations to minimize unexpected failures.
Locked or Disabled Accounts
Users or processes attempting to log in with locked or disabled accounts can result in failed logon attempts that appear suspicious but are benign.
Recommendation: SOC teams should cross-check failed logon events with account lockout or disablement records to verify whether the activity is expected. Monitoring FailureReason fields can help distinguish legitimate administrative actions from potential threats.
Third-Party Application or Service Failures
Some third-party applications or services may fail to authenticate correctly due to configuration issues, causing repeated failed logon attempts. These are often benign, but they can create noise in the logs.
Recommendation: Review the source of the failed logons, particularly in the SourceNetworkAddress or TargetUserName fields, to identify whether the failures are originating from legitimate services. Once identified, these can be excluded from alerts to reduce unnecessary noise.
Common False Negatives
False negatives occur when legitimate threats go undetected, often due to improper filtering or misconfiguration of monitoring tools. These can be more dangerous than false positives, as they allow attackers to operate undetected.
Overly Aggressive Filters
In an effort to reduce noise, some organizations may configure their SIEM tools or log monitoring systems to ignore or filter out certain types of failed logons, such as repeated user errors. While this reduces false positives, it can also filter out genuine attacks, such as brute-force attempts.
Recommendation: SOC analysts should carefully tune their SIEM rules to ensure that genuine attack patterns, such as large-scale brute-force attempts or credential stuffing, are not filtered out along with benign user errors. Consider using adaptive thresholds based on the source or type of logon (e.g., network logons vs. local interactive logons).
Missed Correlation with Other Events
Failed logons are often one part of a larger attack pattern, such as privilege escalation or lateral movement. If failed logon attempts (Event ID 4625) are not correlated with related successful logons (Event ID 4624) or privilege assignment events (Event ID 4672), critical signs of an ongoing attack may be missed.
Recommendation: Correlate failed logons with successful logons, privilege escalation attempts, or Kerberos ticket events (Event ID 4768/4769) to build a more complete picture of user activity. SOC teams should look for patterns where failed logons are followed by successful access, which could indicate a successful brute-force or Pass-the-Ticket attack.
Missed Logon Attempts from Unmonitored Systems
In some cases, false negatives can occur if not all log sources are properly monitored or included in the SIEM’s alerting rules. Attackers may target unmonitored systems or bypass detection by focusing on systems that are less rigorously monitored.
Recommendation: Ensure that all critical systems, including backup servers, domain controllers, and administrative systems, are configured to forward event logs to the SIEM or central log management system. Regularly review log forwarding configurations to ensure comprehensive coverage.
Minimizing False Positives and Negatives
To optimize detection and reduce the impact of false positives and negatives, SOC teams should adopt a balanced approach to event logging and alerting. This includes tuning detection thresholds, correlating events, and implementing dynamic monitoring rules.
Fine-Tuning Alert Thresholds
Set dynamic thresholds for failed logon attempts that trigger alerts based on the behavior of specific accounts or systems. For example, an administrative account may have stricter thresholds for alerting than a regular user account, given its higher value to attackers.
Using Contextual Information
Leverage contextual information such as the LogonType, SourceNetworkAddress, and SubStatus Code fields to distinguish between benign and suspicious failed logon attempts. For example, failed logons using LogonType 3 (network logon) from external IP addresses may warrant immediate investigation, while LogonType 2 (interactive logon) failures from local machines may be less critical.
Automating Logon Correlation
Use automation tools or SIEM platforms to correlate failed logons with other security events, such as successful logons or privilege assignment attempts. This allows for more effective investigation and reduces the likelihood of missing important attack patterns.
Continuous Tuning and Review
As new threats emerge and system configurations change, it’s important to continuously tune alerting and monitoring rules. Regularly review and adjust thresholds, correlation rules, and log sources to ensure comprehensive detection without overloading the SOC team with false positives.
Windows Event ID 4625 is a critical tool for detecting failed logon attempts, but understanding the difference between false positives and genuine threats is essential for effective monitoring. By fine-tuning alert thresholds, correlating failed logons with other events, and ensuring comprehensive log coverage, SOC analysts can minimize false positives and negatives, enhancing their ability to detect and respond to credential-based attacks.
Conclusion
Windows Event ID 4625, which logs failed logon attempts, plays a pivotal role in security monitoring and security incident detection. By analyzing these logs, SOC analysts can detect early signs of credential-based attacks such as brute-force attempts, credential stuffing, privilege escalation, and insider threats. The significance of Event ID 4625 lies in its ability to provide visibility into failed authentication attempts, offering critical insights into both benign user errors and potential malicious activity.
Incorporating Event ID 4625 into a broader security strategy that includes effective monitoring, correlation with other security events, and the application of best practices allows organizations to significantly enhance their detection and response capabilities. SOC analysts who understand the nuances of failed logons and implement appropriate response measures can proactively prevent security incidents, thereby reducing the risk of credential theft, privilege escalation, and lateral movement across the network.
Additional Resources
For SOC analysts and security professionals aiming to deepen their understanding of Windows Event ID 4625 and improve their overall security monitoring practices, having access to the right tools, documentation, training programs, and reference materials is essential. This chapter provides a curated list of additional resources that can help in investigating and responding to failed logon attempts, enhancing both technical knowledge and practical skills.
Microsoft Documentation and Resources
Microsoft provides extensive resources that explain how Windows events, including Event ID 4625, are logged and how to interpret the data fields. These official documents are an excellent starting point for understanding the technical details of Windows Event ID 4625 and related event logs.
Recommended Microsoft Resources
1) https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4625
2) https://learn.microsoft.com/en-us/windows/security/operating-system-security/device-management/windows-security-configuration-framework/windows-security-baselines
Training Programs and Certifications
Training and certification programs help SOC analysts build expertise in handling security incidents related to failed logons, log analysis, and overall threat detection. These programs provide practical knowledge on how to detect and respond to attacks such as brute-force, credential stuffing, and privilege escalation.
Recommended Training Programs
1) https://www.eccouncil.org/train-certify/certified-soc-analyst-csa/
2) https://mad20.io/
SIEM Tools for Log Analysis
Security Information and Event Management (SIEM) tools are essential for correlating, analyzing, and alerting based on Windows event logs, including Event ID 4625. These platforms help SOC analysts aggregate log data from multiple sources and generate insights into failed logon attempts, allowing for faster detection and response to threats.
Recommended SIEM Tools:
Threat Intelligence Platforms
Threat intelligence platforms can help SOC analysts enrich log data, such as failed logon attempts, with contextual information from real-world threats. These platforms provide actionable intelligence, allowing organizations to identify and respond to known attack vectors and adversaries targeting authentication systems.
Recommended Threat Intelligence Platforms
Security Best Practices and Frameworks
Adopting industry best practices and frameworks helps ensure that organizations are following standardized methods for handling authentication events and preventing credential-based attacks.
Recommended Security Frameworks
To effectively monitor and respond to failed logon attempts captured by Windows Event ID 4625, SOC analysts need access to a variety of tools, training, and threat intelligence platforms. By leveraging these additional resources, organizations can enhance their log analysis capabilities, reduce the risk of credential-based attacks, and strengthen their overall security posture. Continuous learning, proper training, and integration with SIEM tools and threat intelligence are crucial to staying ahead of evolving threats and ensuring proactive security incident detection and response.
Annex
Security Incident Report - INC-2024-10-04-003
Unauthorized Access Attempt via Windows Event ID 4625
Security Incident Overview
Security Incident Title: Multiple Unauthorized Failed Logon Attempts Detected (Event ID 4625)
Security Incident ID: INC-2024-10-04-003
Date of Security Incident: October 4, 2024
Date of Detection: October 4, 2024
Detected By: Jane Doe, SOC Analyst
Detection Method: SIEM Alert (Triggered by a high volume of failed logon attempts from external IP addresses targeting privileged accounts)
Security Incident Severity Level: Medium
Security Incident Classification: Credential-Based Attack (Brute-Force / Credential Stuffing)
Summary of the Security Incident
At 9:00 AM UTC on October 4, 2024, SOC Analyst Jane Doe detected multiple failed logon attempts flagged by Windows Event ID 4625. The failed logons targeted privileged accounts, including AdminUser01 and ServiceAccount01, across several critical systems, including the domain controller and the RDP server. The logon attempts originated from unfamiliar external IP addresses, raising suspicions of a brute-force or credential stuffing attack. The security incident was escalated to John Smith, Security Incident Response Manager, for investigation and containment.
Timeline of Events
Details of Compromised Accounts and Resources
Affected Accounts
Compromised Resources
Systems Targeted
Network Resources
Investigative Actions
Lead Investigator: John Smith, Security Incident Response Manager
Supporting Analysts: Jane Doe, SOC Analyst (Initial Detection), Sarah White, Forensics Specialist, Tom Lee, Network Analyst
Key Events Investigated:
-- TargetUserName: AdminUser01 (Privileged Account)
-- TargetDomainName: CORPDOMAIN
-- SourceNetworkAddress: 203.0.113.15 (Unfamiliar External IP)
-- FailureReason: 0xC000006A (Incorrect Password)
-- LogonType: 10 (RemoteInteractive Logon, indicating an RDP attack)
-- TargetUserName: ServiceAccount01 (Service Account)
-- TargetDomainName: CORPDOMAIN
-- SourceNetworkAddress: 198.51.100.20 (Unfamiliar External IP)
-- FailureReason: 0xC000006A (Incorrect Password)
-- LogonType: 3 (Network Logon)
Immediate Actions Taken
Containment Led By: John Smith, Security Incident Response Manager
Investigative Steps Led By: Sarah White, Forensics Specialist
Reporting Risk and Impact
Risk Assessment
Severity: Medium – Although no successful logons (Event ID 4624) were detected, the targeting of high-privilege accounts raised the risk level, as these accounts provide broad access across the network.
Business Impact
Potential for unauthorized access to critical systems and services, though no confirmed data breach or lateral movement was detected at this stage.
Legal and Compliance Considerations
All findings and actions have been documented in compliance with internal audit policies and regulatory frameworks. This report will also serve as evidence for any legal proceedings or internal audits that may arise as a result of this security incident.
Conclusion and Next Steps
Security Incident Resolution
Root Cause Analysis
The attack is likely a result of credential-based exploitation (brute-force or credential stuffing), attempting to gain unauthorized access to privileged accounts.
Recommended Actions
This Security Incident Report outlines the detection, investigation, and response process for multiple failed logon attempts detected via Event ID 4625. The actions taken have successfully contained the security incident, and further investigation is ongoing to ensure the security of all privileged accounts.
Glossary
Access Control
A set of policies and technologies used to manage who is allowed to access specific resources. Strengthening access control prevents unauthorized users from accessing systems and limits lateral movement in case of compromised accounts.
Account Lockout
A security measure that locks an account after a predetermined number of failed logon attempts. Account lockouts are often used to prevent brute-force attacks.
Active Directory (AD)
A Microsoft directory service that handles authentication, authorization, and account management within a Windows domain network. Failed logon events like Event ID 4625 are logged on domain controllers in an Active Directory environment.
AES Encryption
Advanced Encryption Standard (AES) is a symmetric encryption algorithm widely used for securing sensitive data, including passwords and authentication tokens.
Brute-Force Attack
An attack method where an adversary systematically tries multiple username-password combinations to gain access to a system. Repeated failed logons (Event ID 4625) are commonly seen during brute-force attacks.
Credential-Based Attack
A type of attack in which an adversary uses stolen or guessed credentials (e.g., passwords) to access a system. Examples include brute-force, credential stuffing, and Pass-the-Ticket attacks.
Credential Dumping
A technique where attackers extract stored credentials, such as password hashes, from a system. This technique is often a precursor to attacks like Pass-the-Ticket or Golden Ticket.
Credential Stuffing
A technique where attackers use previously compromised credentials from one service to attempt to log into another service. Event ID 4625 often logs failed attempts during credential stuffing attacks when invalid passwords are used.
Cyber Kill Chain
A framework that describes the various stages of a cyberattack, from initial reconnaissance to achieving the attacker’s objectives. Failed logon attempts often occur during the Delivery and Exploitation phases of the Kill Chain.
Domain Controller (DC)
A server in a Windows domain network that manages user authentication and enforces security policies. Event ID 4625 logs failed logon attempts that occur when users or systems try to authenticate with the domain controller.
Event ID 4624
A Windows event that logs successful logon attempts. Correlating Event ID 4625 (failed logons) with Event ID 4624 helps analysts detect and respond to credential-based attacks.
Event ID 4625
A Windows event that logs failed logon attempts. This event provides visibility into authentication failures due to incorrect passwords, account lockouts, disabled accounts, and other reasons. Event ID 4625 is critical for detecting credential-based attacks like brute-force, credential stuffing, and privilege escalation.
Event ID 4768
A Windows event that logs requests for Ticket Granting Tickets (TGTs) in Kerberos authentication. Failed logon attempts related to Kerberos requests may be part of a larger attack like Pass-the-Ticket or Golden Ticket.
Event ID 4769
A Windows event that logs requests for Kerberos service tickets. Failed logons (Event ID 4625) combined with abnormal Kerberos service ticket requests may indicate Kerberos-based attacks.
Golden Ticket Attack
A Kerberos attack where an attacker forges a Ticket Granting Ticket (TGT) using the compromised password hash of the KRBTGT account, giving them access to any service or user in the domain.
Indicators of Attack (IOA)
Patterns of activity or behaviors that suggest an attack is currently in progress. Failed logon attempts, especially when correlated with other suspicious activity, can serve as IOAs.
Indicators of Compromise (IOC)
Forensic data that provides evidence of a past or ongoing security breach. Failed logon attempts from unfamiliar locations or accounts can serve as IOCs.
Kerberos
A network authentication protocol that uses secret-key cryptography to authenticate users and services in a domain. Failed logons related to Kerberos authentication (Event IDs 4768, 4769, and 4625) are often seen in credential-based attacks.
KRBTGT Account
A special account in Active Directory used by the Key Distribution Center (KDC) to encrypt and sign Ticket Granting Tickets (TGTs). Compromising the KRBTGT account allows attackers to create Golden Tickets.
Lateral Movement
A tactic used by attackers to move from one system or account to another within a compromised network. Failed logons may occur as attackers attempt to use stolen credentials for lateral movement.
Least Privilege Access
The security principle that ensures users are given only the permissions necessary to perform their job functions. Implementing least privilege access can prevent attackers from gaining elevated privileges after compromising a low-level account.
Mimikatz
A tool used to extract credentials, including Kerberos tickets and password hashes, from a Windows system. Mimikatz is often used by attackers for credential dumping and forging Golden Tickets.
MITRE ATT&CK
A globally recognized framework that catalogs adversarial tactics and techniques based on real-world observations. Failed logons (Event ID 4625) are linked to several techniques in the MITRE ATT&CK framework, including brute-force attacks and credential stuffing.
Multi-Factor Authentication (MFA)
An authentication method that requires users to provide two or more verification factors, such as a password and a one-time code. MFA significantly reduces the risk of successful attacks even after multiple failed logon attempts.
Pass-the-Ticket Attack
An attack where an adversary uses a stolen Kerberos ticket to gain access to network resources without needing the account password. Event ID 4625 logs failed logon attempts during this attack if the tickets are not valid or are misused.
Privilege Escalation
A technique used by attackers to gain higher levels of access within a system, often through misconfigured permissions or vulnerabilities. Failed logons targeting administrative accounts can indicate attempts at privilege escalation.
Remote Desktop Protocol (RDP)
A protocol used to remotely access and control a computer. Failed logon attempts (Event ID 4625 with LogonType 10) targeting RDP connections may signal brute-force or lateral movement attacks.
Service Account
A special account used by applications or services to interact with the operating system or network resources. Service accounts are often targeted in attacks, and failed logon attempts on these accounts can signal misconfigurations or attacks.
SIEM (Security Information and Event Management)
A platform used by SOC teams to collect, aggregate, and analyze log data from across the network. SIEM tools help correlate failed logons (Event ID 4625) with other security events to detect and respond to potential threats.
Ticket Granting Ticket (TGT)
A special ticket issued by the Key Distribution Center (KDC) in the Kerberos protocol. It is used by users to request access to network services without needing to authenticate multiple times.
Windows Event Logs
Logs generated by the Windows operating system to record important events, including logons, account changes, and system alerts. These logs are critical for detecting and investigating failed logon attempts (Event ID 4625).