Clop, the notorious ransomware group, began targeting Oracle E-Business Suite customers three months ago and started exploiting a zero-day affecting the enterprise platform to steal massive amounts of data from victims as early as Aug. 9, Google Threat Intelligence Group and Mandiant said in a report Thursday. 

“We’re still assessing the scope of this incident, but we believe it affected dozens of organizations. Some historic Clop data extortion campaigns have had hundreds of victims,” John Hultquist, chief analyst at GTIG, said in a statement. “Unfortunately large scale zero-day campaigns like this are becoming a regular feature of cybercrime.”

The new timeline provided by Google’s incident response firm and security researchers confirms malicious activity against Oracle E-Business Suite customers began almost three months before Clop sent extortion emails to executives of alleged victim organizations demanding payment on Sept. 29. 

Oracle disclosed the critical zero-day vulnerability — CVE-2025-61882 — Saturday, two days after it said its customers had received extortion emails following exploitation of vulnerabilities it previously identified and addressed in a July security update. 

The widespread attack spree actually involved at least five distinct defects, including the zero-day, that were chained together to achieve pre-authenticated remote code execution, watchTowr researchers said earlier this week.

Researchers at watchTowr reproduced the full exploit chain after obtaining a proof of concept and published a flow chart depicting how attackers chained multiple vulnerabilities together. 

“It’s currently unclear which specific vulnerabilities or exploit chains correspond to CVE-2025-61882, however, GTIG assesses that Oracle EBS servers updated through the patch released on Oct. 4 are likely no longer vulnerable to known exploitation chains,” Google said in the report.

Researchers identified suspicious traffic that may point to early attempts at exploitation prior to Oracle’s July security update, but Google has not confirmed the precise nature of that activity. 

Many customers remain exposed and potentially vulnerable to attacks. Shadowserver scans found 576 potentially vulnerable instances of Oracle E-Business Suite on Oct. 6, with the majority of those IPs based in the United States.

Clop’s ransom demands have reached up to $50 million, according to Halcyon. “We have seen seven- and eight-figure demands thus far,” Cynthia Kaiser, senior vice president of Halcyon’s ransomware research center, told CyberScoop.

Investigations into Clop’s activity underscore the stealthy nature of the threat group’s operations, including the use of multi-stage fileless malware designed to evade file-based detection. Other critical details remain unknown and cybercriminals from other groups have complicated analysis through unsubstantiated claims. 

Mandiant said it observed artifacts on Oct. 3 that overlap with an exploit leaked in a Telegram group dubbed “Scattered LAPSUS$ Hunters.” Yet, Google hasn’t gathered enough evidence to definitively link the malicious July 2025 activity with this exploit. 

“At this time, GTIG does not assess that actors associated with UNC6240 (also known as “Shiny Hunters”) were involved in this exploitation activity,” Google said in the report. 

While multiple pieces of evidence indicate Clop is behind the attacks, Google said it’s possible other threat groups are involved.

Clop has successfully intruded multiple technology vendors’ systems, particularly file-transfer services, allowing it to steal data on many downstream customers. The threat group achieved mass exploitation as it infiltrated MOVEit environments in 2023, ultimately exposing data from more than 2,300 organizations, making it the largest and most significant cyberattack that year.

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