WinRAR

Russia-aligned threat actor TA488 (Void Blizzard, Laundry Bear) exploited CVE-2025-66376, a critical XSS vulnerability in Zimbra Collaboration Suite webmail, for at least five months in 2025 via crafted emails to gain persistent access, exfiltrate user credentials, 2FA codes, and bulk emails from Ukrainian government and US defense industrial base targets.

CVE-2026-14191 describes an out-of-bounds heap write vulnerability in WinRAR and UnRAR when processing RAR5 recovery volumes (.rev), allowing an unauthenticated attacker to achieve remote code execution on a victim's system by tricking a user into opening a specially crafted archive.

Roundup of Microsoft security advisories published in July 2026.

The FrostyNeighbor threat actor is targeting Ukrainian governmental organizations with spearphishing emails containing malicious PDFs that deliver a JavaScript dropper (PicassoLoader) and ultimately a Cobalt Strike beacon.

Adversaries use WinRAR or 7-Zip to create encrypted archives in preparation for data exfiltration, using command-line arguments to enable encryption functionality.

This rule detects attempts to execute Jscript/Vbscript files from archive files, a common method for delivering malicious scripts by identifying unusual parent-child process relationships where scripting utilities are launched from archive programs, indicating potential exploitation.