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Rogue ScreenConnect Installations Across Unrelated Hosts Suggest Worm-Like Activity
Huntress observed rogue ScreenConnect deployments with worm-like VBScript propagation across unrelated organizations, prompting a ConnectWise advisory on file transfer behavior.
Huntress identified multiple incidents in late August 2026 where social engineering led to rogue ScreenConnect remote access clients deployed on victim machines, which then spawned wscript.exe to run four VBScript payloads (1.vbs through 4.vbs) for profiling, telemetry collection, and persistence via a WindowsServiceHost Run key. Modified ScreenConnect clients propagated the VBScript chain to connected endpoints, creating worm-like spread. ConnectWise published an advisory on September 3, 2026, confirming an issue affecting file transfer behavior in both cloud and on-premises ScreenConnect deployments, with a CVE and fix expected within the week; partners were advised to review and disable TransferFiles permissions in the interim.
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Rogue ScreenConnect Clients Spread Four-Stage VBScript Chain to Newly Connected Hosts
Huntress says rogue ScreenConnect clients spread a four-stage VBScript chain delivering backdoors, privilege-escalation tools, or an XMRig miner to newly connected hosts.
Huntress identified three unrelated August 2026 incidents using a Quick Assist tech-support scam, a phishing-delivered MSI installer, and a fake Geek Squad refund form to install rogue ScreenConnect clients. Each client repeatedly spawned wscript.exe to run 1.vbs through 4.vbs, which profiled the host, enumerated installed security products, and downloaded stage-specific payloads from Dropbox. Depending on detected state, payloads included a user-level ScreenConnect backdoor, UAC-bypass privilege escalation tooling, or tunneling utilities with an XMRig cryptocurrency miner. Infected clients re-infected newly connected hosts, creating worm-like propagation, and ConnectWise issued an advisory about affected file transfer behavior in ScreenConnect.
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Modified ScreenConnect Clients Used in Worm-Like Campaign
Huntress warns of worm-like attacks using modified ScreenConnect clients to spread VBScript payloads; ConnectWise issued an advisory.
Campaigns starting in late August use social engineering, including Quick Assist abuse, to install rogue ScreenConnect clients that spawn wscript.exe and deploy four VBScript files for reconnaissance, staging, and PowerShell execution. The attackers persist via User Run Keys, attempt UAC bypass, install UltraViewer, and propagate the VBScript chain to other connected ScreenConnect endpoints. ConnectWise published an advisory about a file transfer behavior issue affecting cloud and on-premises ScreenConnect, with a CVE identifier and fix expected within a week; it recommends disabling file transfer meanwhile.
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New Python-Based Payload MechaFlounder Used by Chafer
Unit 42 identified MechaFlounder, a new Python backdoor used by the Chafer group to target a Turkish government entity via HTTP-based C2.
Unit 42 reports that in November 2018 the Chafer group targeted a Turkish government entity, reusing the win10-update[.]com infrastructure reported earlier in 2018 by ClearSky. The new secondary payload, tracked as MechaFlounder, is Python compiled with PyInstaller and acts as a backdoor supporting file upload/download and command execution. It beacons over HTTP using anomalous GET requests containing the username and hostname, suggesting a custom C2 server rather than a standard web server. Code overlap with OilRig's Clayside VBScript was noted, but Chafer and OilRig remain tracked as separate groups.
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NOKKI Almost Ties the Knot with DOGCALL: Reaper Group Uses New Malware to Deploy RAT
Unit 42 links NOKKI malware to North Korea's Reaper group, uncovering the Final1stspy dropper that deploys the DOGCALL RAT in politically motivated attacks.
Unit 42 analyzed the NOKKI malware family used in politically themed attacks against Russian and Cambodian speakers since July 2018. The researchers linked NOKKI to the Reaper group, publicly attributed to North Korea, whose custom DOGCALL RAT uses third-party hosting services to upload data and receive commands. A previously unreported family, Final1stspy, was found deploying DOGCALL, sharing a unique base64-to-hex deobfuscation routine with NOKKI droppers. Attacks used malicious Microsoft Word macros that download and execute payloads while opening decoy documents.
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Russia-Aligned Hackers Use GuardBreaker Prompt Injection to Disrupt AI Malware Analysis
Russia-aligned group UAC-0099 embeds GuardBreaker prompt injection in a VBScript comment to make AI malware scanners refuse analysis of a MATCHBOIL loader.
ESET identified a UAC-0099 VBScript used in an early-stage intrusion against a target in Ukraine that hides a safety-triggering comment (a question about building a nuclear weapon) intended to make AI code scanners refuse to continue analysis. The script downloads MATCHBOIL, a loader associated exclusively with UAC-0099, alongside familiar anti-analysis checks for IDA and Wireshark. The technique turns the AI triage process itself into the attack target, risking missed detections or benign misclassification of malicious samples.
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Hackers Weaponize AI Safety Guardrails to Hide Malware From LLM-Powered Security Scanners
ESET says Russia-aligned actor UAC-0099 hid guardrail-triggering comments in VBScript to derail LLM-based malware scanners in Ukraine.
ESET researchers linked a technique named GuardBreaker to Russia-aligned threat actor UAC-0099 during an attack against an organization in Ukraine. The group embedded a safety-sensitive, weapon-related request in a VBScript comment so an LLM-powered analysis tool might interpret it as an instruction and refuse or truncate analysis before reaching the malicious code. The VBScript downloaded MATCHBOIL, a C#-based loader used by the group alongside MATCHWOK and DRAGSTARE. OWASP guidance recommends treating code comments and metadata as untrusted input, sanitizing it, and never treating an LLM refusal as a clean verdict.
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