The RIG exploit kit is undergoing an evolution to version 3.0 as malware authors seek to infect an increasing volume of victims. A research team at security vendor Trustwave has managed to infiltrate the RIG ecosystem, which is made up of a command and control system as well as third parties that use RIG as a service to exploit users.
Arseny Levin, lead security researcher at Trustwave, said the RIG 2.0 code was leaked in February by a disgruntled RIG reseller. With the RIG 3.0 update, the exploit kit authors are now abandoning the reseller model and selling the service directly. Levin said that Trustwave based its initial research into RIG 3.0 on the source code that was leaked with RIG 2.0 and then escalated from there, eventually gaining access to the RIG back-end servers.
"We had access to the RIG administration panel and then got access to their database," Levin told eWEEK. "They did a good job of securing their source code, so it was a really complex task to get access, which required a team effort from Trustwave researchers."
Levin noted that exploit URLs delivered by RIG 3.0 are now more difficult to detect, thanks to a new dynamic model of URLs. In the past, URLs used by RIG were relatively static, which meant that signature-based detection was possible in security platforms, he said. The way the RIG 3.0 exploit kit works is largely by way of malvertising links, according to Levin. Malvertising is a form of malicious online advertising where the destination landing page of the ad leads to some form of malware exploit delivery. He said that RIG 3.0 lands as a low-cost advertising network bid, making use of low frequency keywords in an effort to help avoid detection.
Overall, the Trustwave research team has seen a high degree of success so far from the RIG 3.0 exploit kit.
"We have been monitoring the two main RIG servers for approximately the last six weeks, and during that period we have monitored about 3.5 million hits to RIG landing pages," Levin said. "Out of that number, 1.25 million machines were actually exploited, providing an infection rate of approximately 34 percent, which is scary."
Looking at the numbers, with 3.5 million RIG landing page hits and 1.25 million infections, that means that approximately 2.25 million users were not actually infected after hitting a RIG 3.0 landing page. Levin said that the uninfected users might have patched their Adobe Flash version or had some form of anti-malware protection present to avoid infection from RIG 3.0.
RIG 3.0 largely makes use of existing known vulnerabilities that have already been patched by application vendors, with Adobe Flash exploits being particularly popular. Levin said that CVE-2015-5122, which is a Flash exploit discovered in the code of breached security firm Hacking Team, is particularly popular with RIG 3.0.
Other vulnerabilities that RIG 3.0 makes use of include CVE-2014-6332, a vulnerability in Microsoft's Object Linking and Embedding (OLE) library that was patched in November 2014.
RIG 3.0 is not making much use of Oracle Java vulnerabilities. Levin said that ever since Oracle enabled Click-to-Play by default for Java in 2014, malware authors have largely avoided Java exploits as they are not as successful as they once were.
"RIG is after mass infections, so they go after the low-hanging fruits," Levin said. "They even filter out any non-Windows and non-Internet Explorer traffic."
Trustwave is working with law enforcement about RIG 3.0, though Levin noted that he couldn't provide any specific details.
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.