Memory scraping malware goes after encrypted private information

What’s “pervasive memory scraping” and why is it considered by SANS Institute security researchers to be among the most dangerous attack techniques likely to be used in coming the coming year?

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Simply put, pervasive memory scraping is used by attackers who have gained administrative privileges to successfully get hold of personally identifiable information (PII) and other sensitive data held encrypted in a file system, according to Ed Skoudis, senior security consultant at InGuardians who is also an instructor at SANS events. Evidence of this attack is coming up again and again in data-breach cases, he said.

“Data is encrypted in a file system where it’s stored,” said Skoudis, who joined with Johannes Ullrich, chief research officer at SANS Technology Institute, to speak at the RSA Conference last week on dangerous attack techniques that appear to be on the rise. Though stored encrypted, the data has to be processed by some application and “if you’re processing that data it will be processed in that system unencrypted,” Skoudis pointed out.

Although data encryption is widely regarded as good protection for sensitive data — and may be required under regulations — attackers are probing the chinks in encryption’s armor to steal it. That’s done by taking advantage of the fact that to be processed, data has to be unencrypted, and attackers “go into memory and grab the crypto key” and start “fetching the PII itself from memory.” One interesting aspect about this attack is that “the bad guys want to maintain the end-to-end encryption, too.”

Pervasive memory scraping is not wholly new — the annual Verizon Data Breach report, for example, two years ago identified what it called a “RAM scraper” attack as something first spotted in the retail and hospitality sectors. The Verizon report described the RAM scaper as a “relatively new form of malware designed to capture data from volatile memory within a system” in order to circumvent encryption controls and “capture data in memory where it must be decrypted to be read and processed.” The Verizon report at that time suggested, “The best defense is to keep remote attacks from owning the system.”

One of the tools that attackers can use for pervasive memory scraping is the Metasploit Meterpreter, a software module that works with the open-source Metasploit framework. Researcher Colin Ames is credited with having done pioneering work in showing how it’s possible to hunt for crypto keys, Skoudis said.

Although data-loss prevention (DLP) products and freeware can help in detecting accidental leakage of sensitive data, they may not be enough of a defense against pervasive memory scraping attacks where “the bad guys are encrypting the data and DLP can’t see it,” Skoudis said.

Other types of dangerous attacks expected to be on the rise were also identified. These included attack scenarios related to enterprise migration from IPv4 to IPv6. Here, attackers try to stealthily move about via IPv6 networks that enterprises may not even know are turned on in newer versions of products, while their older firewalls or intrusion-prevention systems may not be looking for IPv6 at all.

“IPads and iPhones are devices already running IPv6,” said Ullrich. “There are no great tools right now to actually monitor it.” IPv6 can constitute a “shadow network” that many IDS and IPS are not yet ready to observe, he added. His advice: “If you don’t need it, turn off IPv6 on your router, on your host, everywhere.”

In another prediction, the infamous Stuxnet malware launched against industrial control systems in Iran is also likely to be the source of inspiration in the coming year for similar attacks. Calling it “Trickle-down Stuxnet,” Skoudis predicted the Stuxnet method that used a stolen signing certificate and sophisticated Windows-based exploits will inspire others to attempt something similar. In addition, Skoudis also pointed out that social networking in general, where users post a plethora of information that attackers may have access to, presents a highly attractive attack platform for the future.

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