SleeperGem Malicious RubyGems Supply Chain Attack

Technical Analysis

The threat actors published typosquatted or impersonating gems—git_credential_manager (v2.8.0-2.8.3) and Dendreo (v1.1.3-1.1.4)—to the public RubyGems repository to trick developers into installing them via automated or manual dependency resolution. Once installed, these gems act as stagers, establishing a foothold on the developer's machine to fetch and execute secondary payloads, a common technique for credential theft, backdoor installation, or further supply chain poisoning of downstream projects. Because the packages masquerade as legitimate developer tooling (credential managers), they are likely to bypass casual scrutiny and be included in build scripts, Gemfiles, or CI pipelines with elevated trust. Development machines and CI/CD runners compromised this way often hold API keys, cloud credentials, and tokens used by AI agent orchestration frameworks and RAG pipelines that pull dependencies from the same ecosystem, meaning a successful compromise could expose secrets used by agentic systems or allow malicious code injection into agent tool-calling environments during build or deployment.

Affected Systems

Developer workstations and CI/CD build systems using RubyGems package manager; specifically environments that installed git_credential_manager versions 2.8.0, 2.8.1, 2.8.2, 2.8.3, or Dendreo versions 1.1.3, 1.1.4

Indicators of Compromise

• git_credential_manager (RubyGems package) v2.8.0
• git_credential_manager (RubyGems package) v2.8.1
• git_credential_manager (RubyGems package) v2.8.2
• git_credential_manager (RubyGems package) v2.8.3
• Dendreo (RubyGems package) v1.1.3
• Dendreo (RubyGems package) v1.1.4

Remediation Steps

1. 1

   Audit installed gems

   Search all Gemfiles, Gemfile.lock files, and installed gem caches across developer machines and CI/CD systems for git_credential_manager and Dendreo in the affected version ranges.

2. 2

   Remove and quarantine malicious packages

   Uninstall the identified malicious gems immediately and isolate affected machines pending forensic review.

3. 3

   Rotate credentials

   Rotate any API keys, git credentials, cloud tokens, or secrets that were present on machines where the malicious gems were installed, especially credentials used by automated agents or CI pipelines.

4. 4

   Implement dependency verification

   Enforce gem checksum verification, use private/internal gem mirrors with vetted allowlists, and enable dependency scanning tools to detect typosquatted or malicious packages before installation.

5. 5

   Monitor for secondary payload activity

   Review endpoint and network logs for unusual outbound connections, process execution, or persistence mechanisms originating from Ruby processes on affected hosts.