Posted by Virus Bulletin on Sep 17, 2012
Dropped PoisonIvy trojan linked to 'Nitro' attacks.
Security researcher Eric Romang has discovered a new zero-day vulnerability in Internet Explorer that is currently being used in the wild by the 'Nitro' gang.
The attack, which is probably used in a drive-by download attack, starts with an HTML file that does some preparatory work and loads a Flash file. This Flash file 'sprays the heap' and then loads a second HTML file in an iframe. This HTML file checks if the user is running Internet Explorer 7 or 8 (in fact, it merely checks if the 'User Agent' is set to either version of the browser) and, if that is the case, exploits the vulnerability to drop an executable onto the victim's machine.
The executable is a variant of the PoisonIvy trojan, which has been used by the Nitro gang in the past. This trojan opens a backdoor on the victim's network and is commonly linked with industrial espionage.
Many security experts like to point out that the overwhelming majority of malware infections use exploits that have been known and patched for a long time, in many cases several years. This is true, and it is a somewhat reassuring fact: it means that merely by applying security patches when they are released, you can keep most threats at bay. In fact, given how much such exploits are worth on the dark grey market, it is unlikely that they are being used to target home users, as this would greatly increase the risk of the exploit being discovered, which in turn would significantly reduce its value.
However, many zero-day exploits, once discovered, are soon after used to target the 'mass-market'. We saw this recently with the Java exploit CVE-2012-4681, which was added to the 'Blackhole' exploit kit before Oracle had released a patch. Those using Internet Explorer 7 or 8 would thus do well to upgrade to a more recent version of the browser.
And of course, organisations that are possible targets of such attacks should be aware that zero-day exploits may be used to target their systems. For them, simply applying patches when they are released is probably not enough to keep the threats out.