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CVE-2016-2056 is a shell command injection vulnerability in Xymon versions 4.1.x, 4.2.x, and 4.3.x before 4.3.25. The vulnerability exists in the web/useradm.c and web/chpasswd.c components, where the adduser_name argument is not properly sanitized, allowing remote authenticated users to inject shell metacharacters and execute arbitrary commands as the webserver user.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository contains a single Metasploit module (modules/exploits/unix/webapp/xymon_useradm_cmd_exec.rb) that exploits a command injection vulnerability (CVE-2016-2056) in Xymon versions prior to 4.3.25. The vulnerability exists in the useradm.sh CGI script, which fails to properly sanitize user input when creating new users via the web interface. Authenticated attackers can inject arbitrary commands into the username field, which are then executed by the system as the web server user. The module supports multiple Unix-like platforms (Linux, Solaris, BSD) and can deliver both direct command payloads and staged payloads (such as reverse shells) using Metasploit's CmdStager. The main attack vector is network-based, targeting the /xymon-seccgi/useradm.sh HTTP endpoint. The exploit requires valid credentials and the Xymon web interface to be accessible. The code is weaponized, as it is part of the Metasploit framework and supports flexible payload delivery.
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