GNU Bourne-Again Shell (Bash) 'Shellshock' Vulnerability

How it was found

GNU Bash versions 1.14 through 4.3 contain a flaw that processes commands placed after function definitions in the added environment variable, allowing remote attackers to execute arbitrary code via a crafted environment which enables network-based exploitation.

Original disclosure: http://www.openwall.com/lists/oss-security/2014/09/24/11

Detailed analysis by lcamtuf:

• http://lcamtuf.blogspot.com/2014/09/quick-notes-about-bash-bug-its-impact.html
• http://lcamtuf.blogspot.com/2014/10/bash-bug-how-we-finally-cracked.html