One runaway AI agent racked up a $50,000 cloud bill
Mandiant's AI Risk and Resilience report details prompt injection, AI supply chain compromises, agent abuse, and a runaway agent that accrued $50,000 in cloud charges.
Mandiant, drawing on Google Threat Intelligence Group (GTIG) observations, warns that poisoned data sources, model dependencies, and extension hooks can turn AI agents into channels for reconnaissance, lateral movement, and sandbox escape. Mandiant responded to incidents involving UNC6780 (TeamPCP), who stole AI service credentials and used prompt injection against AI coding assistants, while GTIG disclosed the first confirmed criminal use of an AI-developed zero-day exploit in a planned mass exploitation campaign. Red team tests showed an AI assistant manipulated into cloning internal repositories to an external GitHub account, and a runaway accounting agent made over 15,000 costly API calls in under an hour, generating roughly $50,000 in cloud charges.
Attacker Hijacks AI Coding Assistant Session, Spreads Shai-Hulud Across About 100 Repositories
Mandiant says an attacker hijacked an AI coding-assistant session at a SaaS provider and spread the Shai-Hulud worm across roughly 100 repositories, stealing secrets.
Mandiant's September 2026 report describes an attacker hijacking an active AI coding-assistant session at an unnamed SaaS provider, then getting a poisoned package recommendation accepted and installing an infostealer via a malicious PyPI package. The attacker stole GitHub OAuth tokens, deployed the self-spreading Shai-Hulud worm across approximately 100 internal repositories, and stole repository secrets and product source code. Poisoning a package in the company's official namespace caused a second employee to pull the compromised version and become infected. Mandiant recommends verifying AI-recommended dependencies against checksums and allowlists, keeping secrets out of extension reach, and routing dependency traffic through internal repositories.
GTIG AI Threat Tracker: From Prompting to Autonomy – The Evolution of Adversarial AI
GTIG's Q2 2026 tracker shows adversaries adopting agentic AI workflows, including credential harvesting in under six hours and supply chain attacks by UNC6780.
Google Threat Intelligence Group's Q2 2026 report documents adversaries moving from basic prompting to agentic AI workflows and automation, including a cloud compromise followed by agent-enabled mass credential harvesting executed in under six hours. It tracks financially motivated actor UNC6780 (TeamPCP) conducting large-scale open source supply chain compromises across PyPI, npm, and Docker Hub since March 2026, deploying credential stealers. The report also highlights growing targeting of proprietary AI models, source code, prompts, and API credentials, plus LLMJacking practices where adversaries steal developer credentials or hijack cloud infrastructure to run unauthorized AI workloads.
Brand Impersonation Takedown: From Whack-a-Mole to Managed Response
Mandiant-tracked group UNC3753 impersonated US professional services firms' brands in 2026; Cyble urges managed takedowns over manual abuse reports.
Cyble describes how Google Mandiant-tracked group UNC3753 targeted US professional services firms between January and May 2026 using brand impersonation, spoofed domains, and fake executive profiles. Manual takedowns fail because phishing pages damage brands within hours while removal takes days. A managed takedown program with continuous monitoring and pre-authorized removal cuts the exposure window from days to hours.