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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

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.

Palo Alto Unit 42 · Aug 17, 2026Ransomware in the wildCVE-2018-15982CVE-2018-4878CVE-2019-11510+1 CVEs

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.

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

FrostyGoop’s Zoom-In: A Closer Look into the Malware Artifacts, Behaviors and Network Communications

Unit 42 dissects FrostyGoop OT malware, which sent Modbus TCP commands to disrupt heating for 600+ apartment buildings in Ukraine.

Palo Alto Unit 42 analyzed new FrostyGoop/BUSTLEBERM samples, the ninth known ICS-centric malware, first used against a Ukrainian municipal energy company by sending Modbus TCP commands to ENCO control devices. The attack caused a two-day heating outage affecting over 600 apartment buildings during sub-zero temperatures. The Go-compiled malware accepts Modbus register operations and timing parameters via command-line arguments or a JSON configuration file, uses an obscure open-source Modbus library, and checks the Windows BeingDebugged flag to evade debuggers. Unit 42 telemetry recorded over 1 million Modbus TCP devices exposed to the internet between September and October 2024.

Palo Alto Unit 42 · 28d agoMalware in the wild

Attackers Expose Ongoing AI Tool Use Targeting Organizations in Latin America

Unit 42 documents two AI-assisted intrusion campaigns against Latin American government, utility, and financial organizations using LLM-orchestrated tooling.

Palo Alto Networks Unit 42 tracks two ongoing intrusion clusters, CL-CRI-1131 (Mexican transportation, federal ministries, municipal water utilities) and CL-CRI-1163 (Brazilian financial sector), both using living-off-the-land techniques, SOCKS5 relays, and custom RATs. The attackers appear to orchestrate operations via commercial LLMs like Claude and GPT-4.1, evidenced by iterative batch scripts and AI-generated tunneling tool naming. The Mexican campaign (also reported as Operation Escaneo by CloudSEK) exfiltrated sensitive data via dynamic-DNS infrastructure with rotated multi-SAN TLS certificates between February and June 2026. This signals broader adoption of AI-enhanced operations by diverse threat groups in the region.

Palo Alto Unit 42 · 13d agoThreat actor in the wild1

Untracked Nightmares: The Threats Hiding Behind Commodity Infrastructure

Unit 42 exposes CL-CRI-1171, a pay-per-install network spreading malware like Insomnia RAT via YouTube channels and SEO poisoning for over two years.

Palo Alto Networks Unit 42 details CL-CRI-1171, a cybercrime cluster operating a pay-per-install (PPI) marketplace that has delivered multiple malware families for at least two years. The group used at least eleven YouTube gaming channels with hundreds of thousands of followers, plus SEO poisoning promoting trojanized software such as a Bluetooth driver and WinDirStat, infecting gamers and corporate endpoints including critical infrastructure and government entities. A single shared loader delivered payloads including Insomnia RAT, ARKTunnel, Docro Hijacker, GCleaner and Socks5Systemz between July 2025 and April 2026, with more than 10,000 distinct loader samples and over 200 rotating C2 domains identified. YouTube terminated the malicious channels after Unit 42 notified the platform.

Palo Alto Unit 42 · 7d agoMalware in the wild1

New Mirai Variant Targeting Network Security Devices

New Mirai botnet variant exploits nine vulnerabilities in SonicWall, D-Link, Netgear, and other devices, with attacks ongoing at publication.

Unit 42 observed attacks exploiting VisualDoor (SonicWall SSL-VPN), CVE-2020-25506 (D-Link DNS-320), CVE-2020-26919 (Netgear ProSAFE Plus), and other flaws, with infrastructure rotating across at least three IP addresses between February 16 and March 13, 2021. Payloads were updated hours after CVE-2021-27561 and CVE-2021-27562 (Yealink Device Management, unauthenticated root RCE) and later added CVE-2021-22502 (Micro Focus Operation Bridge Reporter) and CVE-2019-19356 (Netis WF2419). Successful exploitation invokes wget to fetch shell scripts that download Mirai binaries compiled for multiple architectures and brute-forcers, and attacks were still ongoing when reported.

Palo Alto Unit 42 · 28d agoExploit / PoC in the wildCVE-2020-25506CVE-2020-26919CVE-2019-19356+3 CVEs

xHunt Campaign: New Watering Hole Identified for Credential Harvesting

Unit 42 tied the xHunt campaign to a watering hole on a Kuwait government website used to passively harvest visitors' NTLM credential hashes.

Palo Alto Unit 42 identified a Kuwait government organization's webpage injected with hidden HTML referencing image paths on domains (microsofte-update.com, learn-service.com) tied to xHunt/Hisoka C2 infrastructure. When visitors loaded the page, Windows would attempt SMB/NetBIOS authentication to the remote share, allowing the operators to capture NTLM hashes that could be cracked or relayed. Related DNS redirect activity on xHunt infrastructure in 2019 pointed to additional credential-harvesting interest against Kuwaiti government email servers.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Mirai Variant MooBot Targeting D

Unit 42 observed the MooBot Mirai variant exploiting four D-Link vulnerabilities to compromise unpatched routers for use in DDoS attacks.

Unit 42 captured attacks exploiting four D-Link remote code execution vulnerabilities: CVE-2015-2051, CVE-2018-6530, CVE-2022-26258, and CVE-2022-28958, with three rated critical at CVSS 9.8. The exploits download the MooBot malware, a Mirai botnet variant, from infrastructure at 159.203.15.179 via wget. Compromised devices fall under full attacker control and can be used for distributed denial-of-service attacks. D-Link has published bulletins for all four flaws, but unpatched devices remain exposed.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wildCVE-2015-2051CVE-2018-6530CVE-2022-26258+1 CVEs

Mirai Variant V3G4 Targets IoT Devices

Unit 42 tracked the Mirai variant V3G4 exploiting 13 vulnerabilities across IoT devices and servers from July-December 2022 to build a DDoS botnet.

From July to December 2022, Unit 42 observed three campaigns spreading V3G4, a Mirai botnet variant, by exploiting 13 vulnerabilities, including CVE-2022-26134 in Atlassian Confluence and CVE-2019-15107 in Webmin. The campaigns shared the same C2 domains containing the string 8xl9, nearly identical shell script downloaders, and the same XOR keys, suggesting a single threat actor. The malware brute-forces telnet and SSH credentials, terminates rival botnet processes via a stop list, and receives DDoS commands from its C2. Compromised servers and networking devices are absorbed into the botnet for further attacks.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wildCVE-2012-4869CVE-2014-9727CVE-2017-5173+6 CVEs

Old Wine in the New Bottle: Mirai Variant Targets Multiple IoT Devices

Unit 42 analyzed the Mirai IZ1H9 botnet variant exploiting Tenda, LB-Link, DCN and Zyxel flaws to build DDoS-capable IoT botnets.

Unit 42 observed the Mirai IZ1H9 variant on April 10, 2023, using a shell script downloader lb.sh from 163.123.143.126 to infect exposed Linux servers and networking devices. Campaigns running since November 2021 share infrastructure, near-identical bot functions and the XOR key 0xBAADF00D. The malware exploits CVE-2023-27076 (Tenda G103), CVE-2023-26801 (LB-Link), CVE-2023-26802 (DCN DCBI-Netlog-LAB) and a Zyxel RCE flaw. Compromised devices join a botnet used for DDoS attacks, and the downloader deletes logs and modifies iptables to block SSH, Telnet and HTTP recovery.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wildCVE-2023-27076CVE-2023-26801CVE-2023-26802

IoT Under Siege: The Anatomy of the Latest Mirai Campaign Leveraging Multiple IoT Exploits

Unit 42 tracks a Mirai botnet campaign exploiting over 20 IoT vulnerabilities in routers, cameras and DVRs to build DDoS botnets since March 2023.

Since March 2023, Unit 42 has tracked threat actors exploiting more than 20 IoT vulnerabilities to spread a Mirai botnet variant, first seen downloading payloads from zvub.us on March 14, 2023. Exploited flaws span CVE-2023-1389 (TP-Link Archer), CVE-2022-30525 (Zyxel), CVE-2022-31499 (Nortek) and many router, camera and DVR bugs. The variant decrypts configuration strings with an XOR key derived from 0xDEADBEEF and lacks built-in credential brute forcing, so spreading relies on manual operator exploitation. Two campaigns observed since October 2022 share infrastructure and near-identical samples.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wildCVE-2019-12725CVE-2019-17621CVE-2019-20500+13 CVEs1

Scam Attacks Taking Advantage of the Popularity of the Generative AI Wave

Unit 42 finds about 225 generative AI-themed domains registered daily since ChatGPT's launch, with nearly 29 percent suspicious, fueling scams and PUP delivery.

Palo Alto Networks analyzed new domain registrations containing generative AI keywords such as chatgpt, prompt, and sora since ChatGPT's November 2022 launch, observing around 225 GenAI-related registrations per day. About 28.75 percent of these domains are suspicious, a rate 22 times higher than for general new domains, with registration spikes aligning with milestones like Bing ChatGPT integration, the GPT-4 release, new GPTs, and OpenAI's Sora announcement. Over 72 percent of the domains use gpt or chatgpt keywords, and gpt domains show a 76 percent suspicious rate. Case studies cover PUP delivery, spam distribution, and monetized domain parking, with 35 percent of traffic to these domains directed at suspicious ones.

Palo Alto Unit 42 · Aug 17, 2026Phishing & fraud in the wild1

Network Abuses Leveraging High-Profile Events: Suspicious Domain Registrations and Other Scams

Unit 42 found scammers surge deceptive domain registrations around major events like the 2024 Paris Olympics to run phishing and counterfeit merchandise scams.

Unit 42 analyzed newly registered domains (over 200,000 detected daily from zone files, WHOIS, and passive DNS) containing event-specific keywords, using the 2024 Paris Summer Olympics as a case study. Threat actors register lookalike domains to sell counterfeit merchandise, push fraudulent services, and run phishing, as previously seen with COVID-19-themed and fake ChatGPT tool scams. The article recommends monitoring domain registrations, DNS and URL traffic trends, textual patterns, and verdict change requests to catch event-themed abuse early.

Palo Alto Unit 42 · Aug 17, 2026Phishing & fraud in the wild

Threat Brief: Ongoing Russia and Ukraine Cyber Activity

Ukrainian government sites were defaced via OctoberCMS CVE-2021-32648 while Microsoft-attributed actor DEV-0586 deployed destructive WhisperGate malware.

Unit 42 tracks January 2022 attacks against Ukrainian government websites that were defaced or made inaccessible, which Ukraine attributed to Russia. Attackers exploited CVE-2021-32648, an account takeover flaw in OctoberCMS prior to 1.0.472, by submitting a boolean true as the password reset code to bypass validation. Separately, WhisperGate malware, attributed by Microsoft to DEV-0586, disabled Windows Defender and corrupted files across multiple Ukrainian organizations, using a ransomware-appearing first stage and an HTTPS-beaconing second stage with LOLBINs and anti-analysis techniques.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wildCVE-2021-326481

Exploring the Latest Mispadu Stealer Variant

Unit 42 found a new Mispadu infostealer variant targeting Mexican users via malicious .url files exploiting the SmartScreen CVE-2023-36025 bypass.

Unit 42 discovered a new variant of Mispadu Stealer, a Delphi-based banking trojan first reported in 2019, found while hunting for the Windows SmartScreen bypass CVE-2023-36025. The campaign uses crafted .url files referencing UNC network-share paths with an HTTP port (@80) that forces payload retrieval over WebDAV via rundll32.exe, avoiding SmartScreen warnings. Analyzed samples (~4 KB, compiled 2023-11-12) predate the CVE publication, and ZIP payloads were likely distributed as email attachments, primarily targeting users in Mexico.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wildCVE-2023-360251

Unit 42 Researchers Discover Multiple Espionage Operations Targeting Southeast Asian Government

Unit 42 attributes three espionage clusters targeting a Southeast Asian government to Stately Taurus, Alloy Taurus, and Gelsemium APTs.

Unit 42 investigated espionage attacks starting in late 2022 against multiple governmental entities in a Southeast Asian country, including critical infrastructure, public healthcare, financial administrators, and ministries. Analysis revealed three distinct clusters: CL-STA-0044 attributed to Stately Taurus (Mustang Panda), CL-STA-0045 to Alloy Taurus (GALLIUM), and CL-STA-0046 to Gelsemium. The first cluster used a ToneShell backdoor variant, ShadowPad, China Chopper web shells, Impacket, and credential dumping tools across roughly Q1 2021 to Q3 2023. All three operated with distinct tools, infrastructure, and long-term surveillance tradecraft consistent with APTs.

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

Persistent Attempts at Cyberespionage Against Southeast Asian Government Target Have Links to Alloy Taurus

Alloy Taurus (GALLIUM) compromised Southeast Asian government networks from 2022 to 2023 using Exchange web shells and undocumented .NET backdoors Reshell and Zapoa.

Unit 42 tracked persistent multiwave intrusions at a Southeast Asian government starting in early 2022 and continuing through 2023, attributing the activity with moderate confidence to Alloy Taurus (aka GALLIUM), a Chinese state-aligned espionage group. Attackers exploited Exchange Server vulnerabilities to deploy web shells including China Chopper, then ran reconnaissance with Fscan and WebScan, created administrative accounts, and installed undocumented .NET backdoors named Reshell and Zapoa. They established resilience by installing SoftEther VPN, brute-forced Active Directory credentials with Kerbrute, and dumped credential stores with GoDumpLsass and LsassUnhooker. The campaign reflects long-term espionage tradecraft to maintain a foothold.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Stately Taurus Activity in Southeast Asia Links to Bookworm Malware

Unit 42 links Stately Taurus APT activity in ASEAN region and Myanmar to the decade-old Bookworm malware family via infrastructure overlaps.

Unit 42 connected Stately Taurus (aka Mustang Panda) espionage activity targeting ASEAN-affiliated organizations and Myanmar to the Bookworm malware family, first published in 2015. Earlier attacks delivered the PubLoad stager via DLL sideloading, with a PubLoad variant communicating with C2 at 123.253.32[.]15 while mimicking Windows Update URLs. Three previously unreported loader samples from 2021-2022 used UUID-decoded shellcode loaded via heap allocation and API callbacks, ultimately decrypting and loading Bookworm DLLs. A ToneShell backdoor variant shared debug paths with Bookworm loaders, and the January 2024 CSIRT CTI post corroborated the Myanmar attacks.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Hackers Use LLMs to Generate Exploit Scripts and Automate Post-Exploitation Across Latin America

Unit 42 says Latin American attackers used LLMs to automate post-exploitation in campaigns hitting Mexican government, water utilities, and Brazilian financial firms.

Unit 42 identified two campaigns in Latin America whose operators used commercial LLMs (Claude, GPT-4.1) behind a self-hosted NextChat interface to generate and debug post-exploitation scripts. Cluster CL-CRI-1131 compromised a transportation organization, Mexican federal ministries, and water utilities in Mexico and Ecuador, using native Windows tools and Volume Shadow Copies to dump the SAM registry hive and NTDS.dit. Cluster CL-CRI-1163 targeted Brazilian financial organizations with job-themed phishing, custom RATs, and a Go-based reverse SOCKS5 tunneling utility called SockTz, with nine versions deployed within roughly two hours. Trend Micro tracks related AI-augmented activity as SHADOW-AETHER-040 and SHADOW-AETHER-064.

GBHackersupdated · 6d agofirst · 6d agoThreat actor in the wild 2 sources1

Muhstik Botnet Attacks Tomato Routers to Harvest New IoT Devices

Unit 42 found a Muhstik botnet variant brute-forcing Tomato router web authentication to harvest IoT devices for crypto mining and DDoS attacks.

Palo Alto Networks Unit 42 researchers in December 2019 identified a new Muhstik botnet variant scanning Tomato routers on TCP 8080 and brute-forcing default admin credentials, targeting roughly 4,600 exposed devices found via Shodan. The variant also scans WordPress and Webuzo installations and exploits the Oracle WebLogic deserialization flaw CVE-2019-2725 for unauthenticated remote code execution. Muhstik, active since March 2018, self-propagates like a worm and typically monetizes infections through cryptocurrency mining and DDoS attacks controlled via an IRC C2 channel.

Palo Alto Unit 42 · 28d agoMalware in the wildCVE-2019-2725

Eleethub: A Cryptocurrency Mining Botnet with Rootkit for Self

Unit 42 uncovered Eleethub, a Perl-based Bitcoin mining botnet using a crafted rootkit and libprocesshider to evade detection, still under development with few infections.

Unit 42 discovered an under-development Perl Shellbot campaign that mines Bitcoin using xmrig and emech while evading detection via a rootkit that replaces the ps tool and the LD_PRELOAD-based libprocesshider.so library. Infected devices download a malicious shell script, connect to IRC-based C2 at eleethub.com and the UnderNet network, and can receive commands for UDP/TCP floods, port scans, and HTTP attacks. The botnet can affect Unix systems and Windows 10 hosts running a Linux subsystem, and its operators use the 'Los Zetas' branding, though they are unlikely to be the Mexican drug cartel. Researchers found only a few compromised 'zombies' before the campaign expanded.

Palo Alto Unit 42 · 28d agoMalware in the wild

A Deep Dive Into Attempted Exploitation of CVE-2023

Mirai-like botnet scans exploit TP-Link EOL router flaw CVE-2023-33538 after CISA KEV addition, though observed exploit code is flawed.

Unit 42 observed large-scale automated scans attempting to exploit CVE-2023-33538 in end-of-life TP-Link TL-WR940N, TL-WR740N and TL-WR841N routers after CISA added the flaw to its KEV catalog in June 2025. HTTP GET requests inject commands via the ssid1 parameter at the /userRpm/WlanNetworkRpm endpoint to download and execute an arm7 ELF binary, a Mirai variant related to the Condi IoT botnet. Firmware emulation and reverse engineering showed the observed exploits are flawed and would fail, but the underlying vulnerability is real and successful exploitation requires authentication to the router's web interface. TP-Link confirmed the devices are end-of-life with no patches available and recommends replacing units and eliminating default credentials.

Palo Alto Unit 42 · 28d agoExploit / PoC in the wildCVE-2023-335381

Patchwork Continues to Deliver BADNEWS to the Indian Subcontinent

Unit 42 details Patchwork APT campaigns against the Indian subcontinent using EPS exploits and an updated BADNEWS backdoor targeting Pakistani military and nuclear interests.

Unit 42 observed the Patchwork group (also known as Dropping Elephant and Monsoon) conducting campaigns against targets in the Indian subcontinent using weaponized documents that exploit CVE-2015-2545 and CVE-2017-0261. The documents deliver an updated BADNEWS backdoor that grants attackers full control of victim machines, using dead drop resolvers on legitimate third-party websites for C2 and HTTP for communications. Lures referenced Pakistan Army promotions, the Pakistan Atomic Energy Commission and the Ministry of the Interior, and in late January 2018 the group shifted from CVE-2017-0261 to the older CVE-2015-2545.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wildCVE-2015-2545CVE-2017-0261

Multiple ArtraDownloader Variants Used by BITTER to Target Pakistan

BITTER used three ArtraDownloader variants since 2015 to target Pakistan, China, and Saudi Arabia, deploying BitterRAT and exploiting CVE-2017-11882 in one wave.

Palo Alto Unit 42 documents ArtraDownloader, a previously unreported downloader family used by the suspected South Asian group BITTER, with three variants and roughly 80 unique samples dating back to February 2015. Between September 2018 and January 2019, BITTER used spearphishing documents hosted on compromised Pakistani websites to target Pakistan and, for the first time, Saudi Arabia; one RTF sample exploited the EQNEDT vulnerability CVE-2017-11882. The downloader retrieves BitterRAT over HTTP, uses simple registry keys for persistence, and byte-level string obfuscation. Infrastructure overlap with the previously reported MY24 InPage-exploit payload was also observed.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wildCVE-2017-11882

Tracking Elirks Variants in Japan: Similarities to Previous Attacks

Unit 42 links new Elirks backdoor variants attacking Japanese organizations to 2012 Taiwan attacks, delivered via spear-phishing PDFs exploiting Adobe Flash CVE-2011-0611.

Unit 42 analyzed new Elirks backdoor variants found in an attack on a Japanese business, noting strong similarities to 2012 attacks on Taiwanese ministries. The backdoor retrieves its C2 address from attacker-created accounts on Japanese blog and SNS services. Recent deliveries used an airline e-ticket lure named "E-TKT" with a PDF exploiting Adobe Flash CVE-2011-0611. Shared infrastructure and tactics with the Scarlet Mimic campaign suggest possible ongoing cyber espionage across East Asia.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wildCVE-2011-0611

MILE TEA: Cyber Espionage Campaign Targets Asia Pacific Businesses and Government Agencies

Unit 42 names MILE TEA, a cyber-espionage campaign since 2011 targeting Japanese and Taiwanese businesses and government agencies with e-ticket phishing lures and Elirks-family malware.

Unit 42 tracks the MILE TEA espionage campaign, observed as early as 2011, targeting Japanese trading, petroleum, and mobile companies, a Beijing office of a Japanese public organization, and a Taiwanese government agency. The primary infection vector is spear-phishing emails with attachments, mostly custom executable installers posing as flight e-tickets, dropping Elirks, Micrass, or Logedrut as initial bridgehead malware. Elirks and Logedrut retrieve encrypted C2 addresses from attacker-posted blog articles, decoded with Base64 and TEA or DES ciphers. The campaign's focus shifted from Taiwan to Japan around 2013.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Banking Trojans: Ursnif Global Distribution Networks Identified

Unit 42 maps banking-trojan distribution networks: spam botnets push Shiotob downloaders and Ursnif, KINS, Tinba at Japan and European targets via compromised web servers.

Unit 42 identified the distribution networks behind banking trojan attacks against Japan, Italy, Spain, Poland, Australia, and Germany. A spam botnet delivered 75 unique Shiotob (Bebloh/URLZone) variants across 7 million spam emails, with Shiotob acting mainly as a downloader that installs Ursnif and the Pushdo spam bot from C2 commands. Over 200 malicious files were hosted on 74 compromised, mostly European small-business web servers between April 2015 and January 2017, with localized invoice and photo-themed email lures per target country.

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

UBoatRAT Navigates East Asia

Unit 42 discovers UBoatRAT, a new custom RAT targeting South Korean and video-game industry personnel, delivered via Google Drive with GitHub-based C2 and BITS persistence.

Unit 42 identified UBoatRAT, a new custom remote access trojan first found in May 2017, whose initial version used a public Hong Kong blog service and a compromised Japanese web server for command and control. The latest variants target personnel or organizations related to South Korea or the video games industry, are delivered through Google Drive, and masquerade as Microsoft Word, Excel, or folder icons. The RAT checks for virtualization software and domain join, retrieves its C2 address from a Base64-encoded string in a GitHub-hosted file, uses a custom XOR-encrypted C2 protocol, and maintains persistence via Windows Background Intelligent Transfer Service (BITS) jobs that survive reboots.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wild1

“Tick” Group Continues Attacks

Unit 42 tracks the Tick espionage group attacking Korean and Japanese defense and high-tech targets with Daserf, Minzen, 9002, Invader, and custom Gh0st RAT variants.

The Tick group has conducted long-running espionage attacks against organizations in the Republic of Korea and Japan, focusing on defense and high-tech companies holding intellectual property, and repeatedly attacked one high-profile Japanese target for three years. Unit 42 links the Daserf backdoor, the 9002 RAT, and the Invader backdoor through shared C2 infrastructure used between July 2012 and April 2013. Minzen samples install a "NamelessHdoor" backdoor derived from publicly available code over a decade old, modified with ReflectiveDLLLoader DLL injection, and the group also uses custom Gh0st RAT variants. Tick has shifted from privacy-protected domain registration to compromised websites for C2 infrastructure.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Tick Group Weaponized Secure USB Drives to Target Air

Unit 42 says the Tick group weaponized South Korean certified secure USB drives with SymonLoader malware to reach air-gapped Windows XP systems.

Unit 42 discovered that the Tick cyberespionage group, which targets Japan and South Korea, compromised an ITSCC-certified secure USB drive made by a South Korean defense company and used a new loader named SymonLoader to extract a hidden executable from these drives. SymonLoader only infects Windows XP and Windows Server 2003, suggesting deliberate targeting of legacy air-gapped systems used by government and defense organizations. The group also delivered HomamDownloader and SymonLoader via Trojanized Korean and Japanese software sent as spearphishing attachments. Unit 42 believes the attacks occurred multiple years ago and that this malware is not part of an active campaign.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1

Bisonal Malware Used in Attacks Against Russia and South Korea

Unit 42 details a Bisonal malware variant, active since 2014, targeting Russian and South Korean defense organizations via PDF-disguised spearphishing emails.

In early May, Unit 42 discovered a campaign delivering a Bisonal malware variant against at least one Russian communications security and cryptography company and one unidentified organization in South Korea. The variant, in the wild since at least 2014, introduces a new C2 cipher and rewritten networking and persistence code, with only 14 samples collected to date. Attackers spoofed Russian state corporation Rostec in spearphishing emails carrying an executable disguised with a PDF icon; the dropper decrypts an RC4-encrypted DLL and establishes persistence via a registry Run key. Bisonal has been used since 2013 against government, military, and defense targets in South Korea, Russia, Japan, and India, alongside successors Bioazih and Dexbia.

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

Analysis of Smoke Loader in New Tsunami Campaign

Fake Japanese Meteorological Agency tsunami warning emails delivered Smoke Loader and AzoRult malware to steal credentials from targets in Japan.

A fake tsunami warning email impersonating Japan's Meteorological Agency asked recipients to click a link on a registered fake agency domain, delivering the commodity loader Smoke Loader to targets in Japan. Smoke Loader, active since 2011, is modular, and its payloads have included banking trojans, ransomware, cryptominers, password stealers, and PoS malware; the campaign later also deployed AzoRult. New samples add junk-jump obfuscation, encrypted network traffic and payload files, a unique machine ID used for tracking and encryption, and PROPagate injection into explorer.exe, with persistence via a Startup folder shortcut and RC4-encrypted C2 communication.

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

Tracking OceanLotus’ new Downloader, KerrDown

Unit 42 identifies KerrDown, a new OceanLotus (APT32) downloader active since 2018 targeting Vietnamese speakers via malicious macros and DLL side-loading.

Unit 42 tracks KerrDown, a previously undocumented downloader family used by OceanLotus (APT32) since at least early 2018, primarily targeting Vietnam or Vietnamese-speaking individuals. Delivery uses macro-laced Microsoft Office documents embedding base64-encoded 32-bit and 64-bit DLLs, and RAR archives containing a legitimate program abused for DLL side-loading. KerrDown is dropped as main_background.png, downloads a DES-encrypted payload from a URL, and executes it directly in memory. Researchers used Jaccard-index similarity analysis to identify the new family, connect campaign samples, and infer patterns in the group's working hours and days.

Palo Alto Unit 42 · Aug 17, 2026Malware in the wild1

"Blank Slate" Campaign Takes Advantage of Hosting Providers to Spread Ransomware

Unit 42 profiles the Blank Slate malspam campaign: blank emails with double-zipped attachments delivering Cerber ransomware while cycling abused hosting provider domains.

The Blank Slate campaign sends empty emails containing double-zipped archives with macro-enabled Word documents or JavaScript files that launch PowerShell to download ransomware, primarily Cerber, and occasionally Sage 2.0 or Locky. Unit 42 observed 555 campaign domains over seven months, with actors repeatedly registering new domains and cycling abuse of legitimate hosting providers after takedowns. In a five-day January-February 2017 window, at least eight domains across seven IP addresses were observed hosting Cerber payloads.

Palo Alto Unit 42 · Aug 17, 2026Threat actor in the wild1