CAPEC-695: Repo Jacking
An adversary takes advantage of the redirect property of directly linked Version Control System (VCS) repositories to trick users into incorporating malicious code into their applications.
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Overview
Software developers may directly reference a VCS repository (i.e., via a hardcoded URL) within source code to integrate the repository as a dependency for the underlying application. If the repository owner/maintainer modifies the repository name, changes their VCS username, or transfers ownership of the repository, the VCS implements a redirect to the new repository location so that existing software referencing the repository will not break. However, if the original location of the repository is reestablished, the VCS will revert to resolving the hardcoded path. Adversaries may, therefore, re-register deleted or previously used usernames and recreate repositories with malicious code to infect applications referencing the repository. When an application then fetches the desired dependency, it will now reference the adversary's malicious repository since the hardcoded repository path is once again active. This ultimately allows the adversary to infect numerous applications, while achieving a variety of negative technical impacts.
How the attack works
The phases an attacker typically follows to carry out this attack.
- Step 1Explore
[Identify target] The adversary must first identify a target repository that is commonly used and whose owner/maintainer has either changed/deleted their username or transferred ownership of the repository and then deleted their account. The target should typically be a popular and widely used package, as to increase the scope of the attack.
- Step 2Experiment
[Recreate initial repository path] The adversary re-registers the account that was renamed/deleted by the target repository's owner/maintainer and recreates the target repository with malicious code intended to exploit an application. These steps may need to happen in reverse (i.e., recreate repository and then rename an existing account to the target account) if protections are in place to prevent repository reuse.