Security Experts:

'Bad Rabbit' Ransomware Uses NSA Exploit to Spread

Contrary to initial reports, the Bad Rabbit ransomware that hit Russia and Ukraine this week does in fact leverage an exploit linked to the U.S. National Security Agency (NSA).

Similar to the NotPetya wiper that infected tens of thousands of systems back in late June, Bad Rabbit also uses the Server Message Block (SMB) protocol to spread within the compromised network. However, researchers initially claimed that, unlike NotPetya, the ransomware did not use either of the SMB exploits tracked as EternalBlue and EternalRomance.

It turns out that while Bad Rabbit does not use EternalBlue, it does in fact leverage EternalRomance to propagate in the network. The presence of the exploit was first reported by Cisco Talos and later confirmed by F-Secure.

The EternalRomance vulnerability was addressed by Microsoft in March 2017 with the release of a security bulletin that also patched the EternalChampion, EternalBlue and EternalSynergy exploits.

Details of these flaws were made public by a hacker group calling itself Shadow Brokers earlier this year. The group claims to have obtained these and many other exploits from the NSA and that they were used by one of the agency’s teams known in the cybersecurity industry as the Equation Group.

When the exploits were made public by the Shadow Brokers in April, Microsoft pointed out that they had already been fixed, which has led some to believe that the tech giant learned about the vulnerabilities from the NSA itself.

The initial analysis showed many connections between Bad Rabbit and NotPetya, including targeting of Ukraine and Russia, binaries signed with expired certificates, use of Mimikatz for credential-grabbing, reboots and persistence via scheduled tasks, removal of event logs and USN change journals, and the same type of file encryption and ransomware functionality.

One of the most significant differences is the fact that Bad Rabbit appears to be an actual ransomware and, at least in theory, users can recover their encrypted files if they pay the ransom. NotPetya, on the other hand, has been classified as a wiper due to the fact that the ransom payment functionality is not implemented properly, making the recovery of files impossible.

Another major difference is the fact that Bad Rabbit mostly affected enterprises, particularly in Russia. However, it’s worth noting that many of the victims in Ukraine are high-profile organizations.

NotPetya has been linked to the Russian threat actor known as BlackEnergy, TeleBots and Sandworm Team, which suggests that the same group may be behind the Bad Rabbit attacks as well, although not everyone seems convinced.

An analysis of the Bad Rabbit infrastructure showed that some of the compromised domains used in the attack had been set up since at least July and some of the injection servers were first seen more than a year ago.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.