CVE-2021-44549 : Exploit Details and Defense Strategies

Apache Sling Commons Messaging Mail 1.0.0 is affected by a vulnerability where the SMTPS server hostname is not checked when establishing a TLS connection. This issue was reported by Michael Lescisin.

Understanding CVE-2021-44549

What is CVE-2021-44549?

Apache Sling Commons Messaging Mail lacks the option to enable additional server identity checks for shared mail sessions, leading to a potential man-in-the-middle attack risk.

The Impact of CVE-2021-44549

The vulnerability allows attackers to potentially intercept communications due to the lack of server identity checks.

Technical Details of CVE-2021-44549

Vulnerability Description

SimpleMailService in Apache Sling Commons Messaging Mail 1.0 lacks an option to enable server identity checks for shared mail sessions.
Users can enable these checks by setting a specific property to true.

Affected Systems and Versions

Product: Apache Sling Commons Messaging Mail
Vendor: Apache Software Foundation
Versions: Apache Sling Commons Messaging Mail 1.0.0

Exploitation Mechanism

The vulnerability can be exploited by accessing the session via the message created by SimpleMessageBuilder and setting a specific property to true.

Mitigation and Prevention

Immediate Steps to Take

Set the property mail.smtps.ssl.checkserveridentity to true via the message's session.

Long-Term Security Practices

Ensure server identity checks are enabled for mail servers to prevent man-in-the-middle attacks.

Patching and Updates

Upgrade to Apache Sling Commons Messaging Mail 2.0 where server identity checks are enabled by default.