Multiple suspects believed to be linked to the Clop ransomware gang have been detained in Ukraine after a joint operation from law enforcement agencies in Ukraine, South Korea, and the United States.
The Cyber Police Department of the National Police of Ukraine confirmed that six arrests were made after searches at 21 residences in the capital Kyiv and nearby regions. While it’s unclear whether the defendants are affiliates or core developers of the ransomware operation, they are accused of running a “double extortion” scheme, in which victims who refuse to pay the ransom are threatened with the leak of data stolen from their networks prior to their files being encrypted.
“It was established that six defendants carried out attacks of malicious software such as ‘ransomware’ on the servers of American and [South] Korean companies,” alleged Ukraine’s national police force in a statement.
The police also seized equipment from the alleged Clop ransomware gang, said to behind total financial damages of about $500 million. This includes computer equipment, several cars — including a Tesla and Mercedes, and 5 million Ukrainian Hryvnia (around $185,000) in cash. The authorities also claim to have successfully shut down the server infrastructure used by the gang members to launch previous attacks.
“Together, law enforcement has managed to shut down the infrastructure from which the virus spreads and block channels for legalizing criminally acquired cryptocurrencies,” the statement added.
These attacks first began in February 2019, when the group attacked four Korean companies and encrypted 810 internal services and personal computers. Since, Clop — often styled as “Cl0p” — has been linked to a number of high-profile ransomware attacks. These include the breach of U.S. pharmaceutical giant ExecuPharm in April 2020 and the attack on South Korean e-commerce giant E-Land in November that forced the retailer to close almost half of its stores.
Clop is also linked to the ransomware attack and data breach at Accellion, which saw hackers exploit flaws in the IT provider’s File Transfer Appliance (FTA) software to steal data from dozens of its customers. Victims of this breach include Singaporean telecom Singtel, law firm Jones Day, grocery store chain Kroger, and cybersecurity firm Qualys.
At the time of writing, the dark web portal that Clop uses to share stolen data is still up and running, although it hasn’t been updated for several weeks. However, law enforcement typically replaces the targets’ website with their own logo in the event of a successful takedown, which suggests that members of the gang could still be active.
“The Cl0p operation has been used to disrupt and extort organizations globally in a variety of sectors including telecommunications, pharmaceuticals, oil and gas, aerospace, and technology,” said John Hultquist, vice president of analysis at Mandiant’s threat intelligence unit. “The actor FIN11 has been strongly associated with this operation, which has included both ransomware and extortion, but it is unclear if the arrests included FIN11 actors or others who may also be associated with the operation.”
Hultquist said the efforts of the Ukrainian police “are a reminder that the country is a strong partner for the U.S. in the fight against cybercrime and authorities there are making the effort to deny criminals a safe harbor.”
The alleged perpetrators face up to eight years in prison on charges of unauthorized interference in the work of computers, automated systems, computer networks, or telecommunications networks and laundering property obtained by criminal means.
News of the arrests comes as international law enforcement turns up the heat on ransomware gangs. Last week, the U.S. Department of Justice announced that it had seized most of the ransom paid to members of DarkSide by Colonial Pipeline.