Suite Better Full - Cve20207796 Zimbra Collaboration

All Zimbra Collaboration Suite (ZCS) versions prior to 8.8.15 Patch 7 .

: In March 2025, researchers observed a coordinated surge where approximately 400 IP addresses targeted this flaw across several countries, including the U.S., Germany, and Japan.

Gaining entry to arbitrary internal or external hosts.

This vulnerability has been widely exploited in the wild. Shortly after the publication of the Proof of Concept (PoC) code, automated bots began scanning the internet for vulnerable Zimbra servers. Security researchers observed that threat actors were utilizing this flaw to deploy web shells (such as kthxm.jsp or variations of the "China Chopper" shell) to establish persistent access. In many cases, the attacks were not immediately destructive; instead, actors silently exfiltrated data or used the compromised mail servers to send spam and phishing emails to other organizations.

Always keep Zimbra Collaboration Suite updated. Subscribe to Zimbra’s security announcements and perform regular security audits of custom integrations and exposed servlets. cve20207796 zimbra collaboration suite full

A successful exploitation of CVE-2020-7796 has severe consequences for the Zimbra instance:

Accessing sensitive internal resources protected by firewalls. Data leakage or credential theft.

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 Attacker ] │ │ 1. Sends Malicious HTTP Request with Internal Target Payload ▼ [ Vulnerable Zimbra Server ] (Perimeter/DMZ) │ │ 2. Processes Request Without Input Validation ▼ [ Internal Network Resource ] (Firewalled Database, Metadata APIs, Cloud Infrastructure) Severe Impact & Exploit Vectors All Zimbra Collaboration Suite (ZCS) versions prior to 8

The servlet is supposed to restrict paths to within the Zimbra installation directory. However, due to insufficient sanitization, an attacker could supply a path with directory traversal ( ../ ) or inject command delimiters.

An attacker can exploit this vulnerability without any prior privileges or user interaction. Successful exploitation can lead to:

: Zimbra Collaboration Suite (ZCS) before 8.8.15 Patch 7 .

The core of this vulnerability lies in the WebEx zimlet, a plugin that integrates WebEx meeting functionality into the Zimbra web client. If a user-supplied URL is passed through the vulnerable component without proper sanitization, the server processes it. This vulnerability has been widely exploited in the wild

: Attackers use this SSRF to scan internal infrastructure or chain it with other exploits to achieve deeper access to corporate environments. Recommended Actions

The primary fix is to update your mail server deployment. Synacor addressed this vulnerability in and all subsequent major versions.

Because an SSRF vulnerability effectively converts a highly trusted perimeter mail server into a malicious pivoting proxy, the cascading operational impacts are severe.

file=../../../../../../../../opt/zimbra/bin/zmcontrol&cmd=status&ext=foo

Potentially facilitate the delivery of malware like the Dogkild worm. Widespread Exploitation:

Organizations must prioritize patching immediately, as this vulnerability is listed in CISA's Known Exploited Vulnerabilities (KEV) Catalog .