According to researchers over at F-Secure, the attack code is being actively used to exploit systems of gullible users as early as April 21 and was active up until a few hours ago. Researchers haven’t provided any other detail apart from this. The attack code has been seemingly included in CrimeBoss exploit kit. The vulnerability being exploited is CVE-2013-2423 and as it can be exploited remotely without any authentication, it is advised that you install the patch before you proceed with anything else today.
The F-Secure blog post also makes note of one of the exploit modules available in Metasploit just a day before the exploit code was discovered by researchers. Given that private firms may have had access to this exploit code well in advance before it made it into the wild, availability of the code on Metasploit – an open source framework, is something that raises red flags all around.