Malicious Repo Configs Could Execute Code via Amazon Q Developer Flaw
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A high-severity flaw in Amazon Q Developer's handling of Model Context Protocol (MCP) configuration files allowed attackers to embed malicious configs inside repositories that, once cloned and trusted by a developer, would execute arbitrary code and steal AWS credentials. The root problem was that the IDE plugins automatically launched MCP servers defined in repository configs without requiring explicit user consent, creating a classic supply chain attack vector through developer tooling. This matters because developers routinely clone third-party or unfamiliar repositories, and compromised AWS credentials can lead to catastrophic cloud account takeovers. The attack required minimal user interaction — simply opening a repo and trusting the workspace — making it highly exploitable in normal development workflows.
Tactical Insight
Immediate actions
- Upgrade all Amazon Q Developer IDE plugins to Language Servers for AWS version 1.69.0 or later to apply the official patch.
- Audit recently cloned repositories for unexpected or unfamiliar MCP configuration files that may have been executed prior to patching.
- Rotate any AWS credentials accessible from developer workstations as a precautionary measure if exposure is suspected.
Long-term improvements
- Establish a policy requiring developers to review configuration files (e.g., `.mcp.json`, workspace configs) in unfamiliar repositories before trusting or opening them in IDE environments.
- Implement least-privilege IAM roles for developer workstations so that credential theft yields minimal blast radius.
- Maintain an inventory of all third-party IDE plugins and developer tools, and include them in your vulnerability management program.
Detection measures
- Enable AWS CloudTrail and alert on anomalous API calls or credential usage originating from developer endpoints.
- Deploy endpoint detection and response (EDR) tooling capable of flagging unexpected child processes spawned by IDE applications.
- Monitor for unusual outbound network connections from developer workstations that may indicate credential exfiltration attempts.