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New pro-Ukraine hacker group targets Russian companies with custom ransomware

F6 links new pro-Ukraine ransomware group VantaCore, likely a Thor rebrand, to seven attacks on Russian firms using custom tooling and multimillion-dollar demands.

Russian cybersecurity firm F6 reports that VantaCore, a ransomware group believed to be a rebrand of pro-Ukrainian group Thor, has targeted at least seven Russian organizations with ransom demands reaching millions of dollars, operating as a ransomware-as-a-service operation with a Tor-based victim chat and a leak site. The group uses custom-built tooling including the VantaCore ransomware that encrypts servers and workstations, VantaCoreLoader for distribution, the VantaCoreRAT backdoor, and SnowKiller, which disables antivirus and security software. Initial access relies on poorly secured VPNs and remote-access tools, flaws in internet-facing applications, and credentials stolen from business partners. F6 notes pro-Ukrainian groups increasingly abandoned stock ransomware like LockBit 3 Black and Babuk in 2025-2026 in favor of custom malware.

The Record · 13d agoRansomware

McKesson copes with fallout from data theft extortion attack

McKesson discloses a data theft extortion attack by ShinyHunters affecting oncology and medical-surgical customers, with a reported $55 million demand.

McKesson disclosed that attackers gained access to some of its third-party applications and stole data associated with a subset of customers in its oncology, multispecialty, and medical-surgical business units; the intrusion ran for four days from August 21 and was discovered August 25. ShinyHunters claimed responsibility and listed McKesson on its data-leak site, reportedly demanding more than $55 million with a September 1 deadline. Flashpoint analysts say the group typically uses social engineering and identity weaknesses with valid credentials to access cloud-hosted environments, making the intrusion hard to detect. McKesson, which distributes about one-third of pharmaceuticals used in North America with $403.4 billion in annual revenue, says operations continue and it has reasonable assurance of no ongoing unauthorized activity.

CyberScoop · 15d agoData breach in the wild

Chess.com Leak Exposes 7.3 Million Users — Evidence Points to Scraping

A free 15.5 GB leak exposed 7.3 million Chess.com user records; analysis suggests large-scale scraping via find-friends rather than a server breach.

A 15.5 GB dump containing 7,337,395 Chess.com records appeared on leak forums posted by user V0idix at no cost. Ransomnews confirmed the data is genuine by validating embedded v1 UUID timestamps against registration dates, but found daily-batch collection over nine days and ~7.4% duplicate records, pointing to scraping. The schema includes emails, ratings, subscription tiers and internal Google Ad Manager audience segments not exposed in the public API, and contains no passwords or payment data. Chess.com reported a similar 828,000-record 2023 leak from find-friends abuse and said then that it was not a breach.

Security Affairs · Aug 14, 2026Data breach in the wild