CVE-2023-34192 Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS)

CVE-2023-34192 is a critical cross-site scripting (XSS) vulnerability identified in Zimbra Collaboration Suite (ZCS) version 8.8.15. This flaw allows a remote authenticated attacker to execute arbitrary code by injecting a malicious script into the /h/autoSaveDraft function. The vulnerability stems from inadequate input sanitization, enabling the execution of malicious scripts within the user’s session context.

Affected Systems

The vulnerability specifically affects Zimbra Collaboration Suite version 8.8.15. Organizations utilizing this version are at significant risk, particularly if they have not implemented the recommended patches or mitigations. Given Zimbra’s extensive deployment across various sectors—including government agencies, educational institutions, and enterprises—the potential exposure is considerable.

Mitigation and Remediation Strategies

To safeguard systems against potential exploitation of CVE-2023-34192, the following measures are advised:

• Apply Official Patches: Zimbra has released patches addressing this vulnerability. Administrators should promptly update to the latest version to ensure protection.

  Zimbra Wiki

• Manual Mitigation: If immediate patching is not feasible, Zimbra has provided instructions for manual mitigation. This involves editing a specific data file to neutralize the threat, a process that does not require a service restart, thereby minimizing operational disruption.

  Help Net Security

• Deploy Web Application Firewalls (WAF): Implementing a WAF can offer an additional layer of defense. For instance, NetScaler’s integrated WAF has released signatures specifically designed to detect and block attempts to exploit this vulnerability.

  Citrix Community

Impact of Successful Exploitation

Exploitation of CVE-2023-34192 can have severe consequences, including:

• Data Breach: Attackers may gain unauthorized access to sensitive information such as emails, contacts, and personal data.

• Credential Compromise: Malicious scripts can harvest user credentials, leading to unauthorized system access and potential lateral movement within the network.

• System Integrity Threats: Execution of arbitrary code can compromise server integrity, allowing attackers to install malware, create backdoors, or disrupt services.

Given the critical nature of this vulnerability, immediate action is essential to prevent potential breaches and maintain system security.

Proof of Concept

As of now, specific proof-of-concept (PoC) scripts for CVE-2023-34192 have not been publicly disclosed. However, the vulnerability has been actively exploited in the wild, underscoring the urgency for implementing the recommended mitigations.

In summary, CVE-2023-34192 presents a significant security risk to organizations using Zimbra Collaboration Suite version 8.8.15. Prompt application of patches or recommended mitigations is crucial to protect sensitive data and maintain system integrity.