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UAC-0099 is a Russia-aligned threat cluster active since at least mid-2022 that primarily targets organizations in Ukraine, including the transportation and energy sectors. The group has been linked to initial-access operations that validate compromised environments before follow-on activity by the GRU-linked Sandworm (APT44) group. UAC-0099 commonly uses phishing to deliver archives containing Visual Basic Script launchers disguised as documents. Its operations have included exploitation of WinRAR vulnerabilities and delivery of the LONEPAGE, MATCHBOIL, MATCHWOK, and DRAGSTARE malware families. In 2026, the group abused the normal plugin-loading behavior of a bundled Notepad++ installation to execute the LUNCHPOKE loader, which deployed BURNYBEAR and an updated MATCHBOIL.V2 loader. This chain established scheduled-task persistence, supported command-and-control configuration updates, and downloaded and unpacked additional payloads. BURNYBEAR includes resource-exhaustion behavior when executed without expected arguments, apparently hindering analysis. UAC-0099 has also used anti-analysis measures, including checks for common reverse-engineering and network-analysis tools. It employed the GuardBreaker technique in a malicious script that downloaded MATCHBOIL: safety-sensitive text was embedded in a non-executed comment to induce safety refusals or incomplete results from LLM-assisted malware-analysis systems without changing runtime behavior.
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Who, where, and (when attributed) which flag flies behind the operation. Pulled from open-source reporting and Mallory's analyst review.
Sectors the actor has been observed targeting.
Geographies tied to known operations.
Attributed origin per open-source reporting.
29 distinct techniques observed across reporting, grouped by tactic. Hover any cell for the evidence excerpt; click through for MITRE's full description.
8 malware families attributed to this actor across reporting.
3 additional families tracked in Mallory.
1 CVE this actor has used in observed campaigns. 1 of them exploited in the wild.
68 indicators attributed to this actor: domains, IPs, hashes, and other artifacts pulled from reporting. View more in app.
20 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Russia-aligned activity cluster using a GuardBreaker prompt-injection technique: embedding safety-sensitive text in a VBScript comment to induce AI code-analysis tools to refuse or abandon analysis. The script downloads and installs the MATCHBOIL loader; the group has also used phishing-led delivery and includes checks for analysis tools such as IDA and Wireshark.
Russia-aligned UAC-0099 used a VBScript downloader for the MATCHBOIL loader in an early-stage intrusion against a Ukrainian target. The group embedded a policy-triggering prompt in a script comment—a technique termed GuardBreaker—to cause AI-assisted code scanners to refuse or halt analysis, creating an evasion blind spot.
Conducted an early-stage attack against a Ukrainian target using a VBScript downloader/installer for the MATCHBOIL loader. The group used the GuardBreaker technique—an LLM guardrail-triggering comment intended to halt AI-assisted malware analysis—and checked for IDA and Wireshark processes as anti-analysis measures.
Uses the GuardBreaker AI anti-analysis technique: a malicious prompt injection embedded in a VBS-script comment intended to trigger LLM safety controls and prevent or degrade automated malware analysis. The VBS script downloads the MATCHBOIL C# loader for delivery of additional payloads.
Match sector + geo + tech-stack targeting against your real footprint.
Every observed MITRE ATT&CK technique, grouped by tactic.
Families this actor is known to deploy, with IOCs and behavior.
CVEs this actor has used in known campaigns.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Domains, IPs, and hashes tied to this actor, refreshed continuously.