SAN FRANCISCO, CALIF. – RSA Conference 2016 – Researchers with Dell SecureWorks here this week released an open-source homegrown tool that detects when attackers attempt to steal Windows Active Directory domain administrator credentials.
The so-called DCEPT (Domain Controller Enticing Password Tripwire) tool is basically a deception-style “honeytoken” approach to catch the bad guys in the act of scraping domain credentials: it uses phony usernames and passwords for the domain administrator and an intrusion detection mechanism that goes into effect when the attacker takes the bait.
James Bettke, a security researcher with SecureWorks who along with director of malware research Joe Stewart co-wrote the tool, says they were looking to solve the domain credential theft problem that plagues organizations hit by advanced attacks such as cyber espionage. “We wrote an agent component caching fake credentials... and a second component looks for their use on the network,” Bettke says. “We thought, ‘why not release it as open source?’”
Pilfered network administrator credentials are a popular way for attackers to pivot from an infected user machine to full access to the victim organization’s network and servers, and ultimately, their sensitive data. Attackers typically scrape the credentials from system memory, and use those keys to the kingdom to burrow further into the network and steal information.
“They try to scrape additional credentials out of memory, looking for the domain password. If they get that out of memory, they go from being an intruder on a single system to controlling your entire network,” Bettke says. “We thought, wouldn’t it be cool to detect that.”
DCEPT works like this: it places phony credentials on the network as a lure. So if an attacker tries to pull cached credentials from a server, DCEPT detects the activity and then alerts a SIEM or other monitoring mechanism. DCEPT comes as a Docker container build for its server component, Stewart says.
The tool decrypts Kerberos pre-authentication packets and inspects them to see if they were the fake passwords being used in the network. Bettke says the tool could be expanded to support other types of “tripwires” such as database entries or email addresses.
DCEPT, which is available on GitHub, has three components: an agent that places fake credentials into memory (and refreshes them); a generation server that creates random passwords for the lure; and a sniffer, which searches for and detects abuse of the phony credentials.
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