Vulnerability Management Series: Topic 4 -The Crucial Difference: Authenticated vs. Non-Authenticated Vulnerability Scanning

Vulnerability scanning is a fundamental practice used by organizations to assess and identify potential weaknesses in their IT infrastructure. However, not all vulnerability scanning approaches are created equal. Authenticated and Non-Authenticated scans are two different approaches to performing security assessments or vulnerability scans on computer systems or networks.

Let's explore each method and when to use them:

Non-Authenticated Vulnerability Scanning

Non-authenticated vulnerability scanning involves probing a target system without providing any login credentials or authentication data. It operates externally, mimicking the methods a potential attacker might use to identify vulnerabilities. These scans mainly focus on the surface-level vulnerabilities that can be detected without direct access to the target system's internal configuration.

These scans can include:

• Port scanning: Unauthenticated scans look for open ports and services on the target system to identify potential entry points for attackers.
• Banner grabbing: The scanner collects information from service banners (responses from services on open ports) to determine the version and type of software running, which can help identify known vulnerabilities.
• Network-based vulnerability checks: The scanner looks for vulnerabilities in open services without needing to authenticate to the target system.

When to use Non-Authenticated scans:

• Quick and Lightweight Assessment: Unauthenticated scans can be performed quickly, as they do not require setting up and managing credentials for each target.
• External Vulnerability Assessment: When you want to assess the security posture of your system from an external perspective, similar to how a hacker would approach it, unauthenticated scans are more appropriate.
• Compliance and Regulatory Requirements: In some cases, compliance standards or regulations may specifically require external vulnerability assessments to be performed, making unauthenticated scans necessary.

Advantages of Non-Authenticated Scanning:

• Quick and easy to deploy: Since no login credentials are required, non-authenticated scanning can be set up and initiated relatively quickly.
• Provides an external perspective: Non-authenticated scans simulate attacks from outside the network, identifying vulnerabilities that an external attacker might exploit.

Limitations of Non-Authenticated Scanning:

• Limited depth of assessment: Non-authenticated scans cannot assess internal system configurations, missing out on potential vulnerabilities that can only be detected with authenticated access.
• False positives: The lack of authentication may lead to false positives, as some vulnerabilities can only be confirmed or eliminated through internal analysis.

Authenticated Vulnerability Scanning

In contrast, authenticated vulnerability scanning requires providing the scanning tool with valid credentials to access the target system or application. By having authenticated access, the security scanner gains a higher level of visibility into the system and can perform more in-depth scans, which may include:

• Detailed vulnerability scanning: Authenticated scans can access and analyze the system's configuration, installed software, and patches. This allows for a more accurate assessment of vulnerabilities and exposures.
• Configuration checks: The scanner can review system configurations against best practices and security guidelines to identify any misconfigurations that may pose security risks.
• Software inventory: Authenticated scans can provide a comprehensive list of installed software and their versions, which is crucial for assessing potential vulnerabilities related to outdated software.
• Privilege escalation checks: Authenticated scans can verify if a user with limited privileges can escalate their access to higher privileges.

When to use Authenticated scans:

• Comprehensive Vulnerability Assessment: Authenticated scans provide a more comprehensive assessment of the target because they can access and analyze system configurations, installed software, and application-specific vulnerabilities that would be hidden in an unauthenticated scan.
• Validation of Patch Management: Authenticated scans can verify if security patches are correctly applied and detect missing patches, which is crucial for maintaining a secure environment.
• Reduced False Positives: Authenticated scans often result in fewer false positives because the scanner can access more detailed information about the system's state.
• Compliance and Internal Audits: For compliance purposes, authenticated scans are often preferred as they give a clearer picture of the overall security posture.

Advantages of Authenticated Scanning:

• Comprehensive assessment: Authenticated scans have access to the internal system, enabling detection of hidden or restricted vulnerabilities, configuration errors, and missing patches.
• Reduced false positives: By accessing the system directly, authenticated scans provide more accurate results and significantly reduce false positives.

Limitations of Authenticated Scanning:

• Increased complexity: Setting up authenticated scans requires proper access credentials, which might be more challenging to obtain, especially in large, complex environments.
• Potential impact on production systems: In some cases, authenticated scans might cause disruptions, making organizations hesitant to perform them on live, production systems.

Choosing the Right Approach

The choice between authenticated and non-authenticated vulnerability scanning largely depends on an organization's goals, resources, and risk tolerance. For a comprehensive evaluation of an organization's security posture, a combination of both approaches may be the most effective strategy.