Cve20207796 Zimbra Collaboration Suite Full !!link!! -

While 2020 saw several high-profile vulnerabilities in Zimbra (notably CVE-2020-27988 and CVE-2020-28016), one flaw stands out for its severity and the chilling simplicity of its exploitation: . This vulnerability, rated Critical (CVSS 9.8) , allows an unauthenticated attacker to achieve full Remote Code Execution (RCE) on the underlying Zimbra server, leading to complete compromise of the email infrastructure.

Introduction In the landscape of enterprise email and collaboration tools, Zimbra Collaboration Suite (ZCS) has long been a favorite for organizations seeking an alternative to Microsoft Exchange. Its robust feature set, open-source core, and scalability make it a prime target for nation-state actors and ransomware gangs alike. cve20207796 zimbra collaboration suite full

https://zimbra.example.com/proxy?file=/some/localfile.txt 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. The critical oversight: The servlet endpoint that allows proxying to internal services (like the mailboxd admin port on localhost) did not enforce authentication. Even worse, certain endpoints of the servlet allowed execution of system commands via the Command or Extension functionality. Its robust feature set, open-source core, and scalability

But the actual working exploit uses the ProxyServlet to access the local Mailboxd service’s admin interface, which in turn allows command execution via a crafted soap request. The critical oversight: The servlet endpoint that allows

The flaw resides in how the servlet validates (or fails to validate) the file parameter. In a typical request:

POST /service/extension/UserServlet HTTP/1.1 Host: target.zimbra.com Content-Type: application/x-www-form-urlencoded file=../../../../../../../../opt/zimbra/bin/zmcontrol&cmd=status&ext=foo