Cross-Site Scripting Vulnerability Identified in Synacor Zimbra Collaboration Suite

What changed

A cross-site scripting (XSS) vulnerability has been identified in the Classic UI of Synacor's Zimbra Collaboration Suite (ZCS). This flaw enables attackers to manipulate Cascading Style Sheets (CSS) @import directives within email HTML, which could lead to unauthorized actions or data exposure.

The vulnerability poses a significant risk as it can be exploited by attackers to execute malicious scripts in the context of the user's session.

Who is affected

Organizations utilizing Synacor's Zimbra Collaboration Suite (ZCS) are at risk due to this vulnerability. The following groups should take particular note:

Administrators and users of Zimbra Collaboration Suite should be aware of the potential for exploitation in their email communications.

• Synacor Zimbra Collaboration Suite (ZCS) users
• Organizations relying on ZCS for email and collaboration
• IT security teams managing ZCS deployments

What to do

It is crucial for affected organizations to assess their current ZCS installations and implement necessary security measures. Users should be vigilant about the content they interact with in emails.

Regular updates and patches from Synacor should be applied promptly to mitigate the risk associated with this vulnerability.

• Review and update ZCS to the latest version as released by Synacor.
• Educate users on the risks of interacting with untrusted email content.
• Monitor for unusual activities that may indicate exploitation attempts.