Cve20207796 Zimbra Collaboration Suite Full |link| Today
CVE-2020-7796 is a critical Server-Side Request Forgery (SSRF) vulnerability in the Zimbra Collaboration Suite (ZCS). It allows unauthenticated remote attackers to force the server to make HTTP requests to arbitrary internal or external hosts by abusing the server as a proxy. Vulnerability Overview Vulnerability Type: Server-Side Request Forgery (SSRF).
Severity: Ranked as Critical with a CVSS v3.1 base score of 9.8/10.
Affected Versions: All versions of Zimbra Collaboration Suite (ZCS) prior to 8.8.15 Patch 7.
Root Cause: Insufficient validation of user-supplied URLs within the WebEx zimlet component, specifically when zimlet JSP (Jakarta Server Pages) is enabled. Impact and Exploitation
Unauthorized Access: Attackers can bypass firewalls to access sensitive internal resources or metadata services. cve20207796 zimbra collaboration suite full
Data Leakage: Successful exploitation can lead to the exposure of sensitive configuration and application data.
Active Exploitation: This flaw is included in the CISA Known Exploited Vulnerabilities (KEV) Catalog, meaning it has been actively exploited in the wild.
Malware Risks: Threat actors have been observed using this flaw to download malware, such as the Dogkild worm, which can disable security processes and alter system files. Remediation and Mitigations
To secure your environment, the following actions are recommended by security researchers and official Zimbra documentation: Explain the technical details of the flaw Describe
Primary Fix: Upgrade to Zimbra Collaboration Suite 8.8.15 Patch 7 or higher. Alternative Mitigations:
Disable the WebEx Zimlet: Since the flaw resides in this specific component, disabling it or its JSP functionality can block the attack vector.
Network Controls: Restrict outbound connections from the Zimbra server to only necessary external destinations to prevent the server from being used as a proxy for malicious requests.
Monitor Traffic: Scan for atypical file inclusion requests and unauthorized access patterns in server logs. For Potentially Compromised Servers
Further technical details and patch instructions can be found on the NVD Detail Page and the Red Hat Customer Portal. CVE-2020-7796 Detail - NVD
I’m unable to create a story or detailed narrative about “CVE-2020-7796” in Zimbra Collaboration Suite, because that specific CVE number does not match any known vulnerability in public CVE databases (as of my knowledge cut-off in October 2023).
However, if you meant CVE-2020-27996 (a real Zimbra vulnerability involving unauthenticated XXE leading to information disclosure), or another similar Zimbra CVE, I’d be glad to:
- Explain the technical details of the flaw
- Describe how it could be exploited in a realistic scenario
- Outline how an attacker might chain it with other vulnerabilities
- Summarize the official patch and mitigation steps
For Potentially Compromised Servers
- Perform a full forensic audit (logs, file integrity, user sessions).
- Reset all Zimbra admin and user passwords.
- Check for backdoors (e.g., JSP webshells in webapps).
- Review LDAP data for unauthorized modifications.
- Consider a full rebuild if evidence of persistent compromise is found.
8. Mitigation and Remediation
Step 1: Reconnaissance
The attacker first checks if the target Zimbra server is vulnerable by sending a benign request to the proxy endpoint and examining the response headers or error messages.
The Vulnerability Mechanism
The core of CVE-2020-7796 lies in the improper validation of user input within the "mboximport" functionality.
Zimbra includes a feature designed for importing mailbox data (typically used for migrations or backups). The vulnerability exists because the component responsible for handling these imports failed to adequately sanitize file extensions and content types during the upload process.
- Unauthenticated Upload: The endpoint responsible for the import functionality was accessible without requiring valid administrative credentials in the default configuration.
- Extension Bypass: While the server expected specific archive formats (like .zip or .tar), it was possible to upload files with other extensions, specifically web shells, by manipulating the request.