UPDATE: TeamPCP (UNC6780 / PCPJack ecosystem) backdoors the Checkmarx Jenkins AST plugin — third Checkmarx supply-chain compromise in three months, SANDCLOCK exfiltrates every CI secret reachable from the runner

UPDATE (TeamPCP / mini-shai-hulud first covered 2026-05-07; PCPJack worm covered 2026-05-10; this is a distinct new artefact in the same actor ecosystem): On 2026-05-09–10 (UTC) TeamPCP (UNC6780) published a backdoored build of the Checkmarx Jenkins AST plugin (version 2026.5.09, marketed under the actor's signature naming "Checkmarx-Fully-Hacked-by-TeamPCP") to the Jenkins Marketplace. Any Jenkins instance configured to auto-update the AST plugin during that window pulled the malicious build and executed the SANDCLOCK credential stealer in the runner context (Checkmarx — Ongoing Security Updates, last updated 2026-05-09; The Hacker News, 2026-05-11; SecurityWeek, 2026-05-11).

SANDCLOCK targets every secret reachable from a typical CI/CD pipeline environment: GitHub Personal Access Tokens, AWS / Azure / GCP credentials, Kubernetes service-account tokens, Docker / OCI registry credentials, SSH keys, and Checkmarx One API tokens. Affected pipelines should be treated as full secrets-compromise events: every credential the runner could read must be rotated and any artefact built or deployed in the window audited. Checkmarx's ongoing-security-updates page specifies plugin version 2.0.13-829.vc72453fa_1c16 (published December 2025) as the safe pinned version; a CVE has been issued as CVE-2026-33634 per the Checkmarx advisory. This is the third Checkmarx-product supply-chain compromise by this actor in three months, after the March 2026 KICS Docker image and the April 2026 VS Code extension defacement — the cadence and the actor's naming convention indicate persistent targeting of the Checkmarx product line specifically, not opportunistic distribution-channel abuse.

Mapped to T1195.002 Compromise Software Supply Chain and T1552.001 Credentials In Files. The GTIG AI Threat Tracker (see § 5) attributes SANDCLOCK specifically to TeamPCP and flags the stealer as explicitly designed to harvest LLM API keys in addition to traditional cloud credentials — consistent with the actor's pivot to monetising stolen LLM access. Defender pivot: inventory every Jenkins plugin auto-update enabled across CI/CD estates; constrain runners to short-lived OIDC-federated credentials (no long-lived PATs in runner env) where the platform supports it; audit Checkmarx One API logs for unexpected source IPs since 2026-05-09.