E-mail Security with DKIM, DMARC and SPF

Email exchange is an essential part of modern communication, yet most people underestimate the complexity behind delivering a simple text message. By the time you draft and click send, your message undergoes an intricate chain of events and checks before reaching the final recipient.

1. Message Transformation: As you draft your message, it's transformed into a transmission-ready file. This file is then uploaded to the originating server, where it awaits complete preparation for internet transmission.
2. Internet Navigation: Once prepared, the message embarks on a journey through the internet. It has a destination determined by the domain, such as [email protected]. The domain domain.x is responsible for directing all messages destined for the kernel to its specific server, identified by a unique IP address.
3. Inbox Arrival: With the IP identified, the message finally arrives at the recipient's server and is deposited into the Kernel's inbox.

However, this journey isn't just about reaching the desired destination. It's also a matter of security.

A Practical Case:

Consider the following scenario:

Bob is an employee of the company "domain.x" who uses the company's domain to communicate with clients. He has an email account, [email protected], and sends messages through this address.

Jam is a client of Bob's and trusts messages sent from [email protected]. Jam has a regular email, [email protected].

Max, an attacker, has Jam's contact and wants to obtain sensitive information. Max manipulates his messages to impersonate Bob, sending a fake message to Jam.

Importance of DKIM, DMARC and SPF:

DKIM (DomainKeys Identified Mail): Assuming Bob has also correctly configured DKIM to digitally sign his emails with the domain "domain.x", Jam's email server would be able to verify the DKIM signature on the received email. If the DKIM signature doesn't match the public key available in the DNS record of the domain "domain.x", Jam's email server can identify that the email sent by Max is fake and didn't actually originate from the domain "domain.x".

DMARC (Domain-based Message Authentication, Reporting, and Conformance): With DMARC configured for the domain "domain.x", Bob can specify email authentication policies and instructions on how unauthenticated emails should be handled by Jam's email server. If Bob has set up a policy of rejection or quarantine for unauthenticated emails, Jam's email server can follow these instructions and take appropriate action upon receiving the fake email sent by Max.

SPF (Sender Policy Framework): Bob, by correctly configuring SPF for the domain "domain.x", specifies which servers are authorized to send emails on behalf of this domain. When Max tries to impersonate Bob, Jam's email server checks the SPF record of the domain "domain.x" to determine if the sending server is legitimate. If SPF is configured correctly, Jam's email server can identify that the fake email sent by Max is not authorized by the domain "domain.x".

Conclusion:

In this case, DKIM, DMARC and SPF play crucial roles in protecting against spoofing attacks and ensuring the authenticity, integrity, and reliability of email communications. Properly configuring these protocols is essential to protect both senders and recipients against fraud and security breaches, as demonstrated in the example of Bob, Jam, and Max.

In summary, implementing security measures such as DKIM, DMARC and SPF is fundamental to ensuring the security and integrity of email communications in an increasingly complex digital world susceptible to cyber threats.