CVE-2020-7796 serves as a reminder of the security risks posed by third-party integrations (Zimlets) in collaborative software. By leveraging the WebEx Zimlet vulnerability, attackers could bypass perimeter security and gain unauthorized access to critical data. Organizations using Zimbra are strongly advised to ensure they are running patched versions to protect against this, and similar, SSRF attacks.
Improper sanitization of user-supplied input in the file name or folder name fields.
CVE-2020-7796 represents a serious risk for any organization running an unpatched version of Zimbra Collaboration Suite. With a critical CVSS score of 9.8 and confirmation of active exploitation, the window for remediation has long passed. Administrators must prioritize applying the official Patch 7 or a newer version immediately to prevent an unauthenticated attacker from abusing their email server to access internal networks and sensitive data.
The primary and most effective remediation for CVE-2020-7796 is upgrading the Zimbra Collaboration Suite. cve20207796 zimbra collaboration suite full
Attackers can leverage a leftover file, httpPost.jsp , located in the WebEx zimlet directory to proxy malicious requests through the vulnerable server. This can be used to bypass firewalls and access internal resources or sensitive data, such as LDAP credentials, that are otherwise protected. Risk and Impact Successful exploitation of this flaw can lead to:
This results in the Zimbra server downloading and executing a reverse shell script.
To evaluate if your environment is exposed to CVE-2020-7796, verify your deployments against these exact structural preconditions: Metric / Condition Risk Profile Details Synacor Zimbra Collaboration Suite (ZCS) Vulnerable Versions All versions prior to 8.8.15 Patch 7 Required Extension WebEx Zimlet must be actively installed Required Flag Zimlet JSP processing must be enabled natively Exploitation Metric High Likelihood (EPSS score historically tracked over 90%) Step-by-Step Remediation Strategy CVE-2020-7796 serves as a reminder of the security
: The official fix implemented in Patch 7 is remarkably simple: it removes the vulnerable httpPost.jsp file entirely via an RPM postinstall scriptlet ( rm -f /opt/zimbra/zimlets-deployed/com_zimbra_webex/httpPost.jsp ). This prevents the exploitation path from being reached.
It is essential to update the Zimbra Collaboration Suite to patch 7 or a later version to eliminate this security risk.
A proof-of-concept exploit has been publicly disclosed, which demonstrates the vulnerability and the potential impact. Improper sanitization of user-supplied input in the file
: If hosted on cloud infrastructure like AWS, GCP, or Azure, the attacker can query the local Cloud Metadata Service ( http://169.254.169 ) to extract highly sensitive IAM security tokens or instance configurations.
CVE-2020-7796 represents a critical security vulnerability discovered in the Zimbra Collaboration Suite (ZCS), a popular email and collaboration platform used widely by enterprises and governments. This flaw allows an unauthenticated remote attacker to upload arbitrary files to the server. In specific configurations, this can lead to Remote Code Execution (RCE), granting the attacker full control over the mail server and access to sensitive email data.