Cybersecurity researchers have raised alarms regarding active exploitation attempts aimed at a newly disclosed security flaw in Synacor’s Zimbra Collaboration platform. The enterprise security firm Proofpoint reported that it began observing this malicious activity on September 28, 2024.
The attacks exploit CVE-2024-45519, a critical vulnerability in Zimbra’s postjournal service that could allow unauthenticated attackers to execute arbitrary commands on affected installations, potentially compromising sensitive data and system integrity. The attack vectors involve spoofed emails that appear to come from Gmail, with bogus addresses in the CC fields designed to trick Zimbra servers into executing the commands embedded within.
These addresses contain Base64 strings that are interpreted by the sh utility, making the attacks particularly dangerous. Proofpoint highlighted that the vulnerability was addressed in recent Zimbra updates, including versions 8.8.15 Patch 46, 9.0.0 Patch 41, 10.0.9, and 10.1.1, which were released on September 4, 2024. Security researcher Alan Li, known as lebr0nli, is credited with discovering and reporting this critical flaw. Although the postjournal feature may not be enabled on most systems, security experts stress the importance of applying the provided patches to prevent possible exploitation.
For Zimbra systems where the postjournal feature is disabled and immediate patch application is not feasible, a temporary measure involves removing the postjournal binary until a patch can be installed. This emphasizes the necessity for organizations to take proactive steps in securing their systems against potential threats. The exploitation attempts appear to have started shortly after Project Discovery released technical details about the vulnerability, which stems from unsanitized user input being processed in the unpatched version.
The flaw allows attackers to inject arbitrary commands, which could lead to significant security breaches. Researchers have identified that the problem lies in how the C-based postjournal binary manages recipient email addresses, highlighting the critical need for users to apply the latest patches and implement comprehensive security measures to protect against these active threats.
Reference:
- https://x.com/threatinsight/status/1841089939905134793
