Shellshock, also referred to as Bashdoor, denotes a critical vulnerability inherent in the Bash shell primarily affecting Linux servers, rather than Linux clients. Specifically, it impacts CGI programs operating on web servers running a Linux OS.
The exploit associated with Shellshock allows malicious actors to execute arbitrary commands on the targeted machine, thereby enabling remote code execution (RCE).
In essence, CGI programs serve a pivotal role in web servers by facilitating dynamic content generation, making the server adaptable to user interactions and requests.
The Common Gateway Interface (CGI) acts as a protocol instrumental in enabling web servers to execute external scripts or programs, thereby fostering the creation of dynamic content such as forms or database interactions for web pages.
These scripts, which can be authored in various programming languages like Perl, Python, or Ruby, are typically housed in the 'cgi-bin' directory on a server.
Upon a user's request for dynamic content, the server engages the CGI script, processes it to generate the desired content, and subsequently transmits it back to the user's browser for display.
Summary:
- Shellshock, aka Bashdoor, is a severe Bash shell flaw affecting Linux servers, notably CGI programs on Linux-based web servers.
- Exploiting Shellshock enables remote code execution (RCE), allowing attackers to run commands on target machines.
- CGI (Common Gateway Interface) is pivotal in web servers, executing external scripts to create dynamic web content.