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Cyber Threat
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Ransomware victim Technology

Openreso

Listed by Arcusmedia on · organisation based in France

openreso.com

Disclosed
Mar 3, 2025
Leak-site listing date
Threat group
Arcusmedia
121 victims listed
Country
France
#6 most targeted
Sector
Technology

ThreatAI analysis

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

About the Arcusmedia group

Arcus Media is a ransomware-as-a-service group that emerged in May 2024, employing double extortion with ChaCha20 + RSA-2048 encryption and recruiting affiliates via a referral-based vetting process, claiming 50+ victims across manufacturing, healthcare, retail, and business services globally. Arcusmedia has listed 115 victims since May 2024.

Incident analysis

Openreso was listed by Arcusmedia ransomware, a group with 121 victims recorded in this database. The listing appeared on the group's leak site on March 3, 2025.

Openreso is based in France and operates in the Technology sector. France ranks #6 worldwide for ransomware disclosures, with 568 victims in this database.

Sector context. Technology companies hold intellectual property, customer data, and source code — all highly valuable assets. A successful ransomware attack can also put downstream customers at risk through supply chain exposure.

Arcusmedia typically follows a double extortion model: data is exfiltrated from the victim's systems before files are encrypted, so the victim faces two demands at once — pay to restore access, and pay to keep stolen data unpublished. The leak site, where this listing appeared, is the lever for the second demand.

Source. Public leak-site disclosures aggregated via the ransomware.live API. The disclosure date is when the listing was published, which can differ from the date of compromise. This site does not publish or link to stolen data. Last updated .

Frequently asked questions

Was Openreso attacked by ransomware?

Yes. Openreso was listed as a victim of the Arcusmedia ransomware group on March 3, 2025. The organisation is based in France and operates in the Technology sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked Openreso?

Openreso was attacked by Arcusmedia ransomware. Arcusmedia is one of the most active ransomware groups, having claimed 121 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the Openreso ransomware attack occur?

The ransomware attack on Openreso was disclosed on March 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 Openreso ransomware attack?

The specific data stolen from Openreso 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 Technology organisation, Openreso likely held source code, intellectual property, and customer data.

How can organisations protect against Arcusmedia attacks?

To defend against Arcusmedia 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.