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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.
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Threat Brief: Maze Ransomware
Unit 42 issued a threat brief on Maze ransomware, noting an uptick across industries and exploitation of Pulse VPN and IE flaws for initial access.
Palo Alto Networks detected an uptick in Maze ransomware samples across finance, healthcare, government, and other sectors. Maze, a variant of ChaCha ransomware first seen in May 2019, is distributed via weaponized Word/Excel attachments and the Spelevo exploit kit leveraging CVE-2018-15982 and CVE-2018-4878, and has used CVE-2019-11510 (Pulse VPN) and CVE-2018-8174 (Internet Explorer). Operators establish a foothold, escalate privileges, move laterally, and exfiltrate files before encryption for extortion leverage.
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Threat Assessment: Egregor Ransomware
Unit 42 assesses Egregor ransomware, a Sekhmet variant likely run by former Maze affiliates using Qakbot, IcedID, and Ursnif for initial access.
Since September 2020, Unit 42 observed Egregor ransomware attacks across the U.S., Europe, Asia-Pacific, and Latin America, coinciding with the Maze team's shutdown announcement. Egregor, a variant of the Sekhmet family, uses commodity malware such as Qakbot, IcedID, and Ursnif for initial access, followed by scripts that modify firewalls, enable RDP, and deploy Cobalt Strike for reconnaissance and exfiltration. A PowerShell script uninstalls the McAfee agent and downloads the Egregor DLL via BITS, executed with the -passegregor10 key. Victims face a three-day ransom deadline before exfiltrated data is published on the Egregor Hall of Shame leak site.
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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.
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Locky Ransomware Installed Through Nuclear EK
Unit 42 reports Locky ransomware delivered through the Nuclear exploit kit using Flash exploits, adding a drive-by path to existing malspam distribution.
Unit 42 observed Locky ransomware being delivered by the Nuclear exploit kit in March 2016 via Flash exploits, following February reports of Neutrino EK distributing Locky. Infections follow a drive-by chain through a gate to the Nuclear EK, which either installs Locky directly or drops a downloader that retrieves it from another domain. Locky retains two distribution paths: malspam with malicious Office macros or JavaScript attachments and exploit kit traffic triggered by casual web browsing.
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CryptoBit: Another Ransomware Family Gets an Update
Palo Alto Unit 42 analyzes updated CryptoBit ransomware distributed via the Rig exploit kit, documenting IOCs, eight sample hashes, and disguise tactics from June 2016.
Unit 42 observed an updated CryptoBit ransomware variant (also tracked as CriptoBit or Mobef) delivered through the Rig exploit kit via the gate domain realstatistics.info between June 17-27, 2016. Infections targeted Windows hosts with out-of-date Flash plugins, and post-infection callbacks used fake user-agents and referrers to disguise traffic to laoismacau.com. At least eight samples were collected, and by June 27 the campaign had begun distributing other malware.
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Afraidgate: Major Exploit Kit Campaign Switches from CryptXXX Ransomware Back to Locky
The Afraidgate exploit kit campaign stopped distributing CryptXXX and now delivers the .zepto Locky variant exclusively through Neutrino EK since July 2016.
By mid-July 2016, the Afraidgate campaign switched from CryptXXX ransomware to consistently delivering the .zepto (Zepto) variant of Locky, using the Neutrino exploit kit after Angler EK disappeared in early June 2016. The campaign starts from compromised websites with injected scripts that redirect to Afraidgate domains and then Neutrino EK landing pages on .top domains. Zepto emerged after the Necurs botnet returned from a three-week outage, bringing new anti-sandboxing and evasion techniques.
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