aws-cdk-lib: OS Command Injection in NodejsFunction Docker Bundling

QFinch assessment

AWS CDK (aws-cdk-lib) is an open-source framework for defining cloud infrastructure in code and provisioning it through AWS CloudFormation. OS command injection issue in the NodejsFunction Docker bundling pipeline in aws-cdk-lib before 2.260.0 that might allow an actor who controls dependency version strings in a project's package.json file to execute arbitrary commands on the host running the CDK toolchain via injected shell metacharacters in the OsCommand helper. This issue requires the actor to control the content of a package.json dependency version string that is processed during Docker-based bundling with nodeModules specified.

Potential impact

During Docker-based Lambda bundling, when the nodeModules option is specified, NodejsFunction assembled a shell command string, including file-operation commands generated by an internal OsCommand helper, from the version strings of the modules listed in nodeModules, and executed it via a shell (bash -c) inside the bundling container. These version strings were interpolated without shell escaping, so values containing shell metacharacters could execute arbitrary commands inside the bundling container - which has read/write bind mounts to the host filesystem - with the privileges of the user running cdk synth, cdk deploy, or cdk diff. Leveraging this issue requires an actor to control a dependency version string for one of the listed modules - for example via an untrusted npm package referenced through nodeModules.