Malware Rotbrow blamed for increase of infected computers.

The latest biannual Microsoft Security Intelligence Report (SIR) reveals the number of malware infected computers has tripled between the third and fourth quarter of 2013. The numbers jumped from 5.8 of every 1,000 computers infected to 17 of every 1,000 computers infected. This sudden increase is blamed on a malware called “Rotbrow” which posed as a browser add-on. The malware was though for some time to be harmlessly benign as it wasn’t exhibiting any of the usual signs of being a malicious program. When Rotbrow eventually activated and began downloading malicious browser extensions, it was already installed on a large number of computers. One of the downloaded malwares was a malicious botnet code known as Sefnit which subsequently downloads more harmful programs, including ransomware.

This latest report does not include the zero-day exploit in IE, which was issued an emergency patch by Microsoft on Monday. It is likely that the timely release of the patch and the fact that infected users have to be viewing an infected web page for the program to execute code remotely greatly mitigates the potential risk.

Original article by Jeremy Kirk.
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