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Threat Assessment: Ryuk Ransomware

Unit 42 assesses Ryuk ransomware amid a CISA/FBI/HHS alert on threats to U.S. healthcare, including the UHS attack that disrupted hospital operations.

A joint CISA, FBI, and HHS alert on October 28, 2020 warned of an imminent threat to U.S. healthcare from operators deploying Trickbot and Ryuk ransomware. Universal Health Services reported a Ryuk attack that disrupted all U.S. UHS sites for weeks, with similar incidents at hospitals in Oregon and New York. Ryuk typically arrives after Trickbot or BazaLoader infections delivered via malicious email, and operators enumerate networks with PowerShell and WMI before encryption. The Trickbot Anchor_DNS module performs DNS tunneling for C2, using connectivity checks to benign domains like ipinfo.io and checkip.amazonaws.com.

Palo Alto Unit 42 · Aug 17, 2026Ransomware in the wild

Mole Ransomware: How One Malicious Spam Campaign Quickly Increased Complexity and Changed Tactics

Unit 42 tracks the new Mole ransomware (CryptoMix family) spread via USPS-themed malspam, with tactics escalating to JavaScript downloaders dropping multiple malware families.

On April 11, 2017, a malspam campaign began distributing Mole ransomware, a CryptoMix-family strain, through USPS-themed emails linking to fake Microsoft Word Online sites offering a bogus Office plugin. By April 13 the campaign added Nemucod JavaScript downloaders installing Mole alongside Kovter and Miuref, and by April 18 it switched to the KINS banking Trojan before moving to speeding-ticket themes and a fake parking services website. Unit 42 notes the rapid tactic changes are likely intended to evade detection, and CryptoMix variants like Mole are typically repackaged within weeks.

Palo Alto Unit 42 · Aug 17, 2026Ransomware in the wild