Cyber Threat Intelligence
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Ransomware Victim Financial Services

Semple, Marchal & Cooper, LLP

Ransomware attack by Interlock · Disclosed June 3, 2025 · 🇺🇸 United States

https:semplecpa.com

Date Disclosed
Jun 3, 2025
2025
Threat Group
Interlock
125 total victims
Country
🇺🇸 United States
Industry
Financial Services

ThreatAI Analysis

Compiled from this incident record and the threat intelligence profile for Interlock. Figures and technique mappings are quoted from the source data, not inferred.

About the Interlock group

Interlock is a ransomware group first observed in September 2024 that targets critical infrastructure sectors including healthcare, government, education, and technology across North America and Europe using double-extortion, with 57+ claimed victims including a major US dialysis provider exposing over two million patient records. Interlock has listed 119 victims since December 2023.

Incident Analysis

Semple, Marchal & Cooper, LLP was targeted by Interlock ransomware, one of the most active ransomware groups in our database with 125 confirmed victims globally. The attack was disclosed on June 3, 2025, when Semple, Marchal & Cooper, LLP appeared on the group's dark web leak site.

Semple, Marchal & Cooper, LLP is based in United States , operating in the Financial Services sector. United States ranks #1 globally for ransomware attacks, with 9,412 victims in our database.

Sector context: Financial sector organisations are targeted for their access to funds, sensitive financial data, and the reputational damage a public breach can cause. Regulatory requirements also increase recovery costs.

Interlock typically employs a double extortion model: first exfiltrating sensitive data from the victim's systems, then deploying ransomware to encrypt files. Victims face two simultaneous threats — paying to restore access and paying to prevent publication of stolen data. The group's leak site publishes victim names and exfiltrated data as leverage.

Data source: This incident record is sourced from public ransomware group leak site disclosures aggregated via the ransomware.live API. Disclosure date reflects when the victim was published on the leak site, which may differ from the initial date of compromise. This platform does not publish or link to stolen data. Last data update: Sep 5, 2026 14:00 UTC.

Frequently Asked Questions

Was Semple, Marchal & Cooper, LLP attacked by ransomware?

Yes. Semple, Marchal & Cooper, LLP was listed as a victim of the Interlock ransomware group on June 3, 2025. The organisation is based in United States and operates in the Financial Services sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked Semple, Marchal & Cooper, LLP?

Semple, Marchal & Cooper, LLP was attacked by Interlock ransomware. Interlock is one of the most active ransomware groups, having claimed 125 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the Semple, Marchal & Cooper, LLP ransomware attack occur?

The ransomware attack on Semple, Marchal & Cooper, LLP was disclosed on June 3, 2025. This date reflects when the victim was published on the threat group's leak site, which may differ from the actual date of initial compromise.

What data was stolen in the Semple, Marchal & Cooper, LLP ransomware attack?

The specific data stolen from Semple, Marchal & Cooper, LLP has not been independently verified by this platform. Ransomware groups typically exfiltrate data before encrypting systems and use the threat of publication to pressure victims. As a Financial Services organisation, Semple, Marchal & Cooper, LLP likely held financial records, client data, and transaction histories.

How can organisations protect against Interlock attacks?

To defend against Interlock and similar threat actors, organisations should: maintain regular offline backups tested for restoration; implement network segmentation to limit lateral movement; deploy multi-factor authentication on all remote access; use endpoint detection and response (EDR) tools; conduct regular phishing and security awareness training; and monitor threat intelligence feeds for indicators of compromise (IOCs) associated with active groups.