Cl0p Ransomware Group: A Threat Profile

Estimated read time 3 min read

Emerging in early 2019, Cl0p (pronounced “Clop”) quickly established itself as a formidable ransomware group. Cl0p is a cybercriminal entity infamous for launching ransomware attacks that encrypt a victim’s data and demand a ransom for its release. But the group’s modus operandi goes beyond mere encryption.

The group’s signature is a ‘double extortion’ technique, which not only involves encrypting the data but also threatening to leak the stolen information if the ransom isn’t paid. This tactic significantly increases the pressure on the victims, as they must pay to avoid reputational damage from potential data leaks.

Infiltration Techniques and Tools

The Cl0p group employs an array of methods to infiltrate their victims’ networks. They exploit vulnerabilities in public-facing applications, leverage phishing campaigns, and use credential stuffing attacks. The group has also been found to leverage the Cobalt Strike threat emulation software in its operations.

In 2023, the Cl0p ransomware group began exploiting a previously unknown SQL injection vulnerability in Progress Software’s managed file transfer (MFT) solution, MOVEit Transfer. The web shell named LEMURLOOT was used to steal data from the underlying MOVEit Transfer databases.

Impact and Consequences

Once the Cl0p ransomware infiltrates a network, it encrypts files, making them inaccessible. The encrypted files are typically appended with the ‘.Cl0p’ or ‘.Ciop’ extension. A ransom note is then left on the infected machines, providing instructions on how to make the payment.

Failure to pay the ransom triggers a threat from the group to publish the stolen data on their leak site, known as “Cl0p^_- LEAKS”. Several high-profile companies have had their sensitive data exposed on this site, leading to reputational damage and potential regulatory issues.

Mitigation and Prevention Measures

In light of the continued threats from Cl0p, it is crucial to have robust cybersecurity measures in place. Organizations are advised to inventory assets and data, identifying authorized and unauthorized devices and software. Admin privileges and access should only be granted when necessary, and a software allow list should be established that only executes legitimate applications.

It’s also recommended to monitor network ports, protocols, and services, and activate security configurations on network infrastructure devices such as firewalls and routers.

To further mitigate the risk, software and applications should be regularly patched and updated to their latest versions, and regular vulnerability assessments should be conducted.

Resilience against Cl0p

In the wake of the ongoing threats posed by Cl0p and similar ransomware groups, the importance of comprehensive and tested incident response plans cannot be overemphasized. Upon detection of a breach, swift actions must be taken to isolate infected systems, assess the extent of the breach, and commence the recovery process.

Done reading? Read our Cyberattack Defense 101: Essential Tips for Everyone guide.

Reza Rafati

Reza Rafati, based in the Netherlands, is the founder of An industry professional providing insightful commentary on infosec, cybercrime, cyberwar, and threat intelligence, Reza dedicates his work to bolster digital defenses and promote cyber awareness.

You May Also Like

More From Author