Threats Tagged 'webdav'

A sophisticated ClickFix campaign variant uses social engineering to trick victims into executing commands via the Windows Run dialog. The technique leverages rundll32.exe to load remote non-DLL payloads by ordinal export #1 over WebDAV connections tunneled through HTTPS port 443. Multiple incidents at a single organization show evolving obfuscation methods including WMI process spawning, caret insertion, and runtime string assembly to evade detection. The attack chain utilizes trusted Windows binaries like pcalua.exe to break process lineage tracking. No files are dropped to disk, and payloads are invoked by ordinal rather than named functions. Successful attacks exfiltrated browser credentials and sensitive documents totaling 13MB. The most obfuscated variant evaded automated EDR detection entirely, being discovered only through proactive threat hunting focused on ordinal execution patterns rather than keyword detection.

Between late April and mid-June 2026, Microsoft observed heightened ACR Stealer activity targeting enterprise environments through ClickFix social engineering lures. This information-stealing malware, associated with Amatera Stealer rebranding and offered as malware-as-a-service, deployed through two distinct campaigns. The first utilized WebDAV-delivered payloads with Python loaders and blockchain-based command-and-control resolution. The second employed a fileless approach using MSHTA and steganography-concealed payloads within images. Both campaigns harvested browser credentials, authentication tokens, and sensitive documents from compromised systems. Threat actors leveraged obfuscated PowerShell scripts, scheduled task persistence, and in-memory execution techniques to evade detection. Notable tactics included masquerading as legitimate software updates, utilizing Windows DPAPI for credential decryption, and targeting PDF and Microsoft 365 documents. The blockchain dead-drop technique enabled dynamic i...