REMnux is a nifty security tool based on Ubuntu. It is essentially a stripped down version of Ubuntu to create a sandbox environment and test for exploits remotely. The official website defines REMnux as,
REMnux is a lightweight Linux distribution for assisting malware analysts in reverse-engineering malicious software. The distribution is based on Ubuntu and is maintained by Lenny Zeltser.
REMnux comes pre-loaded with an array of security related tools to check network activity, check memory activity and to debug and understand code execution.
The features of REMnux are best explained as,
Try REMnux here.