In response to the news of an emerging round of Shellshock attacks which are tapping hosts over SMTP, Gavin Millard, EMEA Technical Director at Tenable Network Security, comments:
"The interesting thing about SMTP attacks is that, if they are email based, its possible that sending one email could infect many different systems which process the email. In tandem, anything that looks at email, such as spam filters based on Linux, could in turn be vulnerable. What that means is that, this latest vector utilising the Bash Bug, is simple to execute and enables remote code execution which could lead to a worm being created and unleashed - potentially with devastating consequences. If you haven't already, hunt down any system that has vulnerable versions of bash and update immediately. Shellshock will be a favourite vulnerability for malicious attackers for some time so we're bound to see more interesting exploits of this massive flaw."