February was the worst month on record for ransomware attacks – and one threat group had a field day

February 2025 was the worst month on record for the number of ransomware attacks, according to new research from Bitdefender.

Analysis from the security company shows the number of ransomware attacks reached 962 last month, marking a significant increase on the year prior in which 425 attacks were recorded.

Of those, 335 were claimed by the Ransomware as a Service (RaaS) group Clop - three times as many as the previous month.

Rather than focusing on specific companies or industries, some ransomware groups, such as Clop, are taking an opportunistic approach by targeting newly discovered software vulnerabilities in edge network devices.

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In particular, these groups are capitalizing on vulnerabilities that have high-risk Common Vulnerability Scoring System (CVSS) scores that allow attackers to take control of a system through Remote Code Execution (RCE).

They're also after flaws that affect internet-facing systems and software, along with instances where proof of concept of the exploitation has already been published by a developer or malicious actor.

"In less than 24 hours of the vulnerability’s public disclosure, threat actors launch automated scanners that scan the internet and establish remote access to vulnerable systems," researchers said.

"After this initial access blitz comes the second stage of the attack – the manual hacking of the victims. This second stage takes time. Attackers need to figure out which systems are worth their effort, and then they have to manually hack their way deeper, typically using living off the land techniques to evade detection."

This delay means the actual ransomware attack or data theft is likely to take place weeks or even months later.

Ransomware attacks aren't subsiding

Over the last five years, Clop has targeted vulnerabilities in the Accellion File Transfer Appliance (FTA), hitting government agencies and universities.

Two years ago, it exploited a flaw in HelpSystems' GoAnywhere Managed File Transfer (MFT) software, breaching healthcare, financial, and manufacturing organizations.

In January this year the group claimed to have hit nearly 60 companies via vulnerabilities in Cleo enterprise file transfer software.

"In Clop's case, our analysis points to their exploitation of two recent vulnerabilities in Cleo file transfer software, CVE-2024-50623 and CVE-2024-55956. These vulnerabilities, rated 9.8 out of 10 in severity, allowed attackers to run commands on vulnerable systems," said the Bitdefender researchers.

"Even though these vulnerabilities were revealed in October and December 2024, the manual part of the attack is what takes time, which can explain why we are seeing these victims now."

To protect themselves, Bitdefender said organizations should prioritize patches for actively exploited vulnerabilities and keep themselves informed about known exploits via the CISA KEV catalog. A flexible patching strategy is key to rapid response.

They should proactively search their network for hidden threats, aiming to discover backdoors before attackers launch their main attack.

Naturally, cybersecurity tools play a key role in helping mitigate potential threats posed by ransomware groups. The firm noted that advanced detection systems such as Endpoint Detection and Response (EDR) or Extended Detection and Response (XDR) services are vital.

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