Seven clues to use to ID who's behind a malware attack

Dark Reading Staff, Dark Reading

June 27, 2013

5 Min Read

The attacker behind the keyboard is human, too: He's a creature of habit, and he sometimes makes mistakes. Identifying telltale patterns used in an attack can provide useful intelligence to help organizations better lock down their information and resources in the bull's-eye.

Malware, phishing emails, and even rigged attachments used in an attack contain some obvious and some hidden clues that can be used to glean intel on who's behind the attack and what they are after -- perhaps an APT looking for intellectual property, or a cybercrime gang trying to pilfer financial information, according to FireEye, which today published a rundown of seven elements of malware that can provide valuable intel and insight on the attackers behind a hack and their motives.

"More and more organizations are under attacks by targeted intrusion groups," says Alex Lanstein, network and systems architect for FireEye. "A lot of people who don't work for malware companies don't know what to look for ... We thought it would be [helpful] for them to understand our workflow."

That doesn't mean that every targeted organization should -- or even can -- conduct CSI-style investigations into malware using clues left behind. Those types of operations are best left to seasoned forensic investigators and researchers, security experts say. But even so, any clues an organization can glean from an attack can help jump-start a more thorough forensics investigation.

The keyboard layout, malware metadata, embedded fonts, DNS registration, written language, remote administration tools (RATs), and behavior patterns all can provide clues to ID attackers, according to FireEye, which built the seven-item checklist from some 1,500 attack campaigns it tracks.

The biggest advantage to gathering this intel is being able to discern whether an attack is targeted or opportunistic, Lanstein says. "It's really about tying together multiple indicators, not just one indicator," he says. And FireEye warns that attack clues can easily be misleading, so it's best to get help from forensic experts and not take any clue at face value.

[How naming names of hackers and pinpointing the beneficiaries of cyberspying and cybercrime attacks translate into a new kind of defense. See Turning Tables: ID'ing The Hacker Behind The Keyboard .]

"Those are the basics you start with," says Dmitri Alperovitch, CTO at CrowdStrike, whose strategy is getting to the bottom of the attacker or group behind an advanced attack rather than on the malware. "We look at the tradecraft, what the attacker is trying to do, [for example]. If you're only looking at malware, everyone is using PoisonIvy, so it's going to be hard to get attribution just on that."

The key is getting beyond concluding the attacker is Chinese, and determining what organization the hacker or hackers belong to and what their strategies are. "Then you can get predictive about what types of victims they are going after," for example, Alperovitch says.

FireEye says the attacker's keyboard layout can reveal where he's from and what language he speaks -- it's easy to spot a Mandarin (GB2312) keyboard used in China -- as can language artifacts found in malware. Even just tracing broken English in a phishing email to a Google translation can pinpoint the attacker's native tongue, FireEye says.

The malware's own metadata can be telling, too: It contains technical information on location and language, and could lead to connections to other attack campaigns. FireEye found source code that it ultimately traced to the Chinese APT1/Comment Group after studying a file in the malware that turned out to be a variant of the WEBC2 malware used by the group.

Even the fonts used in phishing messages can contain clues about the origin of the attack or the attacker's native tongue: In the recently revealed Sanny APT attack, for instance, the rigged document was written in Russian. But it actually used two Korean fonts: "Those font choices reconfirmed existing evidence from other sources that pointed to North Korea, including the author's name and the CnC servers used in the attack. Taken together, the evidence presented a convincing case as to the attacker's origins," FireEye said in its report.

Other elements, such as DNS registration information, can help tie an attacker to a location, and the type of RAT used by the attacker can often help ID him. Then there are the behavioral patterns used by attackers: They often pick the same targets and industries, and employ the same command-and-control servers, according to FireEye. "In the same way, the attacker's exploit toolkits and tactics also help profile the attacker," and can reveal multiple attackers from the same group using the same infrastructure, according to FireEye.

CrowdStrike's Alperovitch notes that while attack indicators can change, the attackers' tradecraft remains mostly the same, such as "how they craft their communications protocols, how they remain stealthy within a company once they hit a company."

"You have to put yourself in the shoes of the attacker. They do hundreds of ops a week. They are not physically able to do everything different for every attack," he says. So there are clues that can be gleaned, he adds.

The full FireEye report, "Digital Bread Crumbs: Seven Clues To Identifying Who's Behind Advanced Cyber Attacks," including screen shots of malware and attack clues, is available here (PDF) for download.

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Dark Reading Staff

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