ALPHV, also known as BlackCat or Noberus, is a financially motivated ransomware group that emerged in September 2021 and rapidly established itself as one of the most sophisticated and prolific ransomware operations observed by researchers at Mandiant, CISA, and the FBI. The group is suspected to have Russian-speaking origins and operates as a Ransomware-as-a-Service (RaaS) platform, with well-documented links to former affiliates of the DarkSide and BlackMatter ransomware operations, suggesting a continuity of personnel and tradecraft across these successive rebrand events. ALPHV is technically distinguished by its use of Rust-based ransomware — an uncommon choice at the time of its emergence — which enabled cross-platform attacks against Windows, Linux, and VMware ESXi environments; the group employs multiple initial access vectors including compromised credentials, phishing, and exploitation of unpatched vulnerabilities, and routinely conducts double and triple extortion by exfiltrating sensitive data prior to encryption and threatening victims with public disclosure on their dedicated leak site, with some cases involving additional pressure through direct contact with victim customers and regulators. ALPHV has claimed responsibility for high-profile attacks against MGM Resorts International, Caesars Entertainment, Reddit, and healthcare provider Change Healthcare — the latter representing one of the most disruptive cyberattacks on the U.S. healthcare sector on record, with a reported ransom payment of approximately $22 million — and has accumulated over 731 known victims across the United States, Canada, Australia, the United Kingdom, and Germany, with particular concentration in business services, manufacturing, healthcare, technology, and financial services sectors. In December 2023, the FBI and international partners conducted a disruption operation against ALPHV's infrastructure and released a decryption tool for victims; however, the group subsequently attempted to rebrand and continued operations before an apparent final collapse in March 2024, following an alleged exit scam against affiliates after the Change Healthcare ransom payment, with law enforcement officially attributing the group's infrastructure seizure shortly thereafter. The group has been linked to 731 public disclosures across our corpus. First observed on a leak site on September 9, 2021; most recent post March 3, 2024. The operation is currently inactive.
Also tracked as: BlackCat, Noberus.
Sector and geography
This disclosure adds to ransomware activity in the Technology sector, which has 3,549 disclosures indexed across all operators we track. Geographically, 4set.es is reported in Spain, a country with 128 ransomware disclosures in our corpus.
If your organisation is affected
A listing by alphv means 4set.es appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.
- Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
- Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
- Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
- Report the incident to your national CERT, INCIBE-CERT (Spain), as required for your jurisdiction.
- Monitor for the data appearing on alphv's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.
How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.
