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Financially-Motivated Iranian Hackers Adopt Dharma Ransomware

Recent Dharma ransomware attacks show that more Iranian hackers have started to engage in financially-motivated operations, threat hunting firm Group-IB reports.

Also referred to as Crysis, the ransowmare family has been offered under a ransomware-as-a-service (RaaS) model since 2016, mainly associated with remote desktop protocol (RDP) attacks. In March this year, however, the malware’s source code became available for purchase.

In a report published on Monday, Group-IB revealed that Dharma ransomware attacks observed in June this year were the work of a newly discovered Iranian hacker group, and that organizations in China, India, Japan, and Russia were targeted. The attackers demanded ransom amounts ranging between 1 and 5 Bitcoin.

The attackers were observed mixing the ransomware with various publicly available tools and focusing their efforts on companies with Internet-facing RDP systems secured with weak credentials. The exact number of victims hasn’t been established yet.

Some of the tools employed in these attacks include the IP port scanner Masscan to identify vulnerable targets, and the RDP brute-forcing tool NLBrute to gain access to the identified machines. In some attacks, the hackers leveraged an exploit for CVE-2017-0213, in an attempt to elevate privileges.

“The newly discovered hacker group suggests that Iran, which has been known as a cradle of state-sponsored APT groups for years, now also accommodates financially motivated cybercriminals,” Group-IB notes.

The hackers behind these attacks, the security researchers note, are novices who likely did not have a clear plan of action once they gained access to the compromised networks.

Using the newly established RDP connection, the attackers attempted to disable built-in antivirus software using Defender Control and Your Uninstaller, while leveraging Advanced Port Scanner to discover accessible hosts in the network.

After network reconnaissance, the attackers attempted to move laterally using RDP. At the final stage of the attack, they would drop and manually execute a variant of Dharma ransomware onto the compromised hosts.

“The fact Dharma source code has been made widely available led to the increase in the number of operators deploying it,” said Oleg Skulkin, senior DFIR analyst at Group-IB. “It’s surprising that Dharma landed in the hands of Iranian script kiddies who used it for financial gain, as Iran has traditionally been a land of state-sponsored attackers engaged in espionage and sabotage.”

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