Complexity Of Security Exploits Increasing

Exploits are getting more complex, reports HP TippingPoint DVLabs, Qualys and The SANS Institute

Cyber attackers are changing their tactics and, unsurprisingly, it’s not to the benefit of users, according to a new security report.

The report features data from Hewlett-Packard’s TippingPoint Digital Vaccine Labs, Qualys and The SANS Institute and notes the increasing use of complex obfuscation techniques for PDF exploits and malicious JavaScript.

Fragmented Attacks

“We see obfuscation techniques and attack complexities that we’ve just never seen before,” explained Mike Dausin, manager of Advanced Security Intelligence at DVLabs. “PDFs are made of sets of streams… usually the exploits come in one stream, one blob of data in the PDF file. Nowadays it’s common to see the exploit being broken up into 10 or more streams within the PDF and actually cross-referencing themselves.”

Dausin added, “We’ve also seen a similar technique in JavaScript-land as well, where you’ll end up with either a set of iFrames or a set of script tags that will reference 10 or more script files… and what will actually come down is… fragments of an exploit that are then [brought] together and executed.”

Since each iFrame contains a separate exploit, the attacker has great control over the techniques employed, the report noted, and adding new exploits or making code changes is “very easy to do”. Each JavaScript fragment is complementary to the other fetched fragments and the exploit will not run unless all of the fragments are present.

“The use of this technique greatly complicates the job of intrusion detection/prevention because each stream must be separately analysed in order to get a clear picture of what the exploit is trying to accomplish,” the report said.

Adobe Reader and Adobe Acrobat have become favourites of attackers in 2010, as exemplified by recent attacks targeting a zero-day bug in the software. According to the report, the amount of time it takes to reduce the number of unpatched machines by 50 percent, termed “half-life”, for Adobe Reader lags behind Microsoft Windows OS. In the last year, the half-life for the Windows OS was 14.5 days while for Adobe Reader it was 65 days.

“We have data available for Adobe Reader showing that the newer version, Reader v9, behaves significantly better than the older versions,” the report said. “Separating the v9 vulnerabilities of Adobe Reader from the vulnerabilities for older versions, v7 and v8, shows that the newest release of Adobe Reader presents a half-life that is roughly equivalent to that of our comparison system, the Windows OS system patches: 15 days.”

While patching remains a problem, the report also emphasised that it is not uncommon for new vulnerabilities to be discovered by different researchers independently.

“This may seem far-fetched but it is now common for ZDI [TippingPoint’s report and reward Zero-Day Initiative] researchers to independently discover the exact same vulnerability as other researchers,” the report said. According to the authors, this has happened 13 times in the first six months of 2010, as compared with 18 times in 2009 and four times in 2007.

“It’s either becoming easier to discover these things, or there are a lot more eyes looking at it,” Dausin told eWEEK. “But the fact remains that, if two legitimate teams are co-discovering vulnerabilities at the exact same time on a regular basis, it’s certainly not a stretch to imagine the black-hat guys are discovering an equal number of them.”

There are also still older threats such SQL SlammerConficker and Code Red circulating. Slammer, which originated in 2004, still triggers TippingPoint’s Intrusion Prevention System (IPS) filters 10 times more than any other filter.

“We still see a lot of really old legacy ways to get compromised,” Dausin said. “We still see large numbers of attacks from older, legacy exploits… It’s important not to forget about password brute-forcing and even just the old legacy acts. Bringing out unconfigured machines on your network is still a great way to get compromised.”