The persistence of the Shellshock vulnerability remains high more than a month after it first surfaced. The latest attacks involved SMTP servers belonging to web hosts. Attackers are using Shellshock exploits targeting the now infamous vulnerability in Bash in order to drop a perl script onto compromised computers.

The script adds the hacked computers to a botnet that receives its commands over IRC. The attack leverages Shellshock as a main attack vector through the subject, body, to, from fields. Once compromised, a perl botnet is activated and beaconing on IRC for further instructions.

In what seems like the most impactful security vulnerability since the OpenSSL Heartbleed affair, a new Internet-wide bug emerged this week in the Bourne again shell (Bash).

While its true severity remains unknown, the Bash vulnerability (also known as “shell shock”) is being talked about everywhere, and you may have even seen your local news anchors discussing the story in front of a green-screen covered in fast-scrolling computer code on last night’s evening news. Bash is present in a very large number of Web-servers and in-home appliances. What is Bash?