Which of the following is a vulnerability in GNU's bash shell (discovered in September of 2014) that gives attackers access to run remote commands on a vulnerable system?

Shellshock is the name given to CVE-2014-6271, a flaw in how GNU bash processed specially crafted environment variables. When bash was invoked as part of a web request (e.g., via CGI scripts), an attacker could append function definitions with malicious commands that bash would execute, enabling full remote code execution on vulnerable systems.

Rootshell is not a recognized CVE or named vulnerability - it does not correspond to any documented bash exploit.

Rootshock is a fabricated term combining elements of real vulnerability names but does not refer to any actual documented vulnerability.

Shellbash is not a recognized vulnerability name and has no association with the 2014 GNU bash disclosure.