Google Threat Intelligence says attackers abused open-source agentic pentesting frameworks ARTEX, CAIRN

[Google Cloud] Google Threat Intelligence Group (GTIG) said that since late August 2026 it and Mandiant have observed multiple threat actors abusing the open-source, multi-agent pentesting frameworks ARTEX, PentAGI and CAIRN, as well as potentially custom harnesses, in incident response engagements, conducting actions across multiple phases of the attack lifecycle including lateral movement, database exploitation and exfiltration preparation. GTIG said its September 2026 report noted that some adversaries were beginning to move from basic prompting to agentic workflows and LLM-enabled automation. According to GTIG, such frameworks can autonomously explore multiple attack paths, troubleshoot errors and achieve objectives in seconds and minutes, increasing the speed and scale of intrusions. GTIG said the mechanics of the intrusions remain the same, relying on compromised credentials and unpatched systems, but automated chaining of complex attack paths introduces a new defensive challenge. Mandiant Consulting recommended control-plane isolation, short-lived credentials, least privilege, segmentation and behavioral detection as long-standing best practices.