Detecting malicious code in program dependencies with Package Hunter
Modern programming ecosystems make code reuse exceptionally easy. No matter the programming task at hand, chances are there is a package in a public registry such as rubygems.org or npmjs.com that implements that task.
While the reuse of publicly available packages reduces the time necessary to write an app, this reuse brings its own set of challenges. Apps quickly depend on hundreds of packages, and programmers often simply just trust that these packages don't contain malicious code. In an ideal world, all depended-upon code is thoroughly vetted before being included in a program – however, this is often unfeasible in practice due to the sheer amount of dependency code that needs to be reviewed and the lack of existing tools to help with vetting dependency code.
Past incidents like malicious code in the popular package event-stream demonstrate that threat actors actively use public package registries as a distribution channel for malicious code. This incident wasn't a single event either. A recent review of open source software supply chain attacks found many similar malicious packages in the wild.
The techniques to deliver malicious dependencies have also become more sophisticated. Earlier this year a security researcher discovered an implementation quirk in many popular package managers, dubbed dependency confusion, that can be used to trick package managers to install dependencies from an attacker-controlled location instead from a trusted, private package registry. Upon installation of the manipulated dependency, the researcher could execute arbitrary code, which could have led to compromise of production systems or CI environments. Existing dependency scanners typically don't detect if a dependency executes malicious code, as these tools are limited to identifying dependencies with known vulnerabilities.
Although GitLab was not directly affected by dependency confusion, they took added measures to ensure packages and registries operate the way they expect them to and are continually monitored and secured, and set out to build tooling to detect and prevent similar incidents in the future.
In response to these challenges and a need for tooling to validate supply chain security, GitLab developed Package Hunter and are releasing it for use by the community. Package Hunter is a tool to analyze a program's dependencies for malicious code and other unexpected behavior by installing the dependencies in a sandbox environment and monitoring system calls executed during the installation. Any suspicious system calls are reported to the user for further examination. Package Hunter uses Falco under the hood for system call monitoring. It currently supports testing NodeJS modules and Ruby Gems. Refer to the docs for more technical details.
Get started with Package Hunter
Package Hunter integrates seamlessly with GitLab. To get started, use the GitLab CI template to add a Package Hunter job to your project and follow the instructions for setting up a Package Hunter server.
At SouthLights we focus on detecting vulnerabilities before they make their way through the Software Development Life Cycle (SDLC). Contact us and integrate DevSecOps practices into your daily routines and stay one step ahead of malicious attacks.
Source: GitLab
