Kaspersky Lab’s heuristic detection protection subsystem has successfully blocked attacks via a zero-day vulnerability in Adobe Flash software. Kaspersky Lab researchers discovered this loophole, which was targeted by exploits distributed via a legitimate government website created to collect public complaints about breaches of the law in the Middle Eastern country.

In mid-April Kaspersky Lab experts analysing data from Kaspersky Security Network, discovered a previously unknown exploit. On closer examination, it turned out that the exploit was using a previously unknown vulnerability in the popular multimedia software Adobe Flash Player. The vulnerability exists in Pixel Bender – an old component, designed for video and photo processing.

Further investigation found that exploits were distributed from a website created in 2011 by the Syrian Ministry of Justice to enable people to lodge complaints about breaches of the law. We believe the attack was designed to target Syrian dissidents complaining about the government.

Kaspersky Lab experts discovered two kinds of exploits in total, with differences in shellcode (a small piece of code used as the payload when exploiting a software vulnerability).

“The first exploit showed rather primitive download-and-execute payload behaviour but the second one tried to interact with Cisco MeetingPlace Express Add-In – a special Flash plugin for co-working, in particular, for joint viewing of documents and pictures on a presenter’s PC desktop.

“This plugin is completely legitimate, but in these particular circumstances it could be used as a spying tool. Moreover, we discovered that this ‘second’ exploit works only if a certain version of Flash Player and CMP Add-In are installed on the attacked PC. This means that attackers probably aimed at a very limited list of victims,” says Vyacheslav Zakorzhevsky, Vulnerability Research Group Manager at Kaspersky Lab.

Immediately after discovering the first exploit, Kaspersky Lab specialists contacted Adobe representatives to inform them of the new vulnerability. After examining the information provided by Kaspersky Lab, Adobe acknowledged that the vulnerability has a zero-day status, and developed a patch which is now available on the Adobe website. The CVE number of this vulnerability is CVE-2014-0515.

“Although we’ve only seen a limited number attempts to exploit this vulnerability, we are strongly recommending that users update their versions of Adobe Flash Player software. It is possible that once information about this vulnerability becomes known, criminals would try to reproduce these new exploits or somehow get the existing variants and use it in other attacks.

“Even with a patch available, cybercriminals would expect to profit from this vulnerability because a worldwide update of software as widely used as Flash Player will take some time. Unfortunately this vulnerability will be dangerous for a while,” says Zakorzhevsky.

It is the second time this year that Kaspersky Lab specialists have discovered a zero-day vulnerability. In February, the company’s specialists discovered CVE-2014-0497 – another zero-day vulnerability in Adobe Flash Player, which allows attackers to stealthily infect victim PCs.

The heuristic detection subsystem is a part of the antivirus engine used in multiple Kaspersky Lab products for home and corporate users, such as Kaspersky Anti-Virus, Kaspersky Internet Security, Kaspersky Endpoint Security for Business and others. Just like a traditional antivirus this system uses a database of signatures to detect malicious software.

But while antivirus technology usually requires a signature for each individual piece of malware, no matter how closely related, heuristic detection can cover whole ranges of malicious programmes. It does this using heuristics – special signatures that detect not only individual pieces of malware but also the whole collections of malicious programmes grouped according to a list of special features.

The heuristic signature which covered the behaviour of the new zero-day exploit in Adobe Flash was added to Kaspersky Lab databases as early as January.

Moreover, during a special test conducted by Kaspersky Lab’ specialists it was discovered that exploits using CVE-2014-0515 are detected accurately by Kaspersky Lab’s Automatic Exploit Prevention technology – another powerful tool to detect unknown threats.

In November 2013 the same technology successfully blocked attacks using a zero-day vulnerability in Microsoft Office software. Also at the end of 2012 it proactively blocked several malicious components which – as it was discovered later – belonged to Red October, a large-scale cyber-espionage campaign detected by Kaspersky Lab researchers in January 2013.