Command injection in Bash - CVE-2014-6271
Published: January 24, 2017 / Updated: August 8, 2023
Bash
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary commands on the target system.
The vulnerability exists due to incorrect parsing of environment variables. A remote attacker can execute arbitrary code on the target system as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution.
Successful exploitation may allow an attacker to gain complete control over vulnerable system.
Exploitation example:
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
Note: this vulnerability was being actively exploited in the wild.