module

Qmail SMTP Bash Environment Variable Injection (Shellshock)

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Disclosed
Sep 24, 2014
Created
May 30, 2018

Description

This module exploits a shellshock vulnerability on Qmail, a public
domain MTA written in C that runs on Unix systems.
Due to the lack of validation on the MAIL FROM field, it is possible to
execute shell code on a system with a vulnerable BASH (Shellshock).
This flaw works on the latest Qmail versions (qmail-1.03 and
netqmail-1.06).
However, in order to execute code, /bin/sh has to be linked to bash
(usually default configuration) and a valid recipient must be set on the
RCPT TO field (usually [email protected]).
The exploit does not work on the "qmailrocks" community version
as it ensures the MAILFROM field is well-formed.

Authors

Mario Ledo (Metasploit module)
Gabriel Follon (Metasploit module)
Kyle George (Vulnerability discovery)

Platform

Unix

Architectures

cmd

References

Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':


    msf > use exploit/unix/smtp/qmail_bash_env_exec
    msf exploit(qmail_bash_env_exec) > show targets
        ...targets...
    msf exploit(qmail_bash_env_exec) > set TARGET < target-id >
    msf exploit(qmail_bash_env_exec) > show options
        ...show and set options...
    msf exploit(qmail_bash_env_exec) > exploit
Title
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