Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. Argo CD starting with version 1.3.0 but before versions 2.1.11, 2.2.6, and 2.3.0 is vulnerable to a path traversal bug, compounded by an improper access control bug, allowing a malicious user with read-only repository access to leak sensitive files from Argo CD's repo-server. A malicious Argo CD user who has been granted get access for a repository containing a Helm chart can craft an API request to the /api/v1/repositories/{repourl}/appdetails endpoint to leak the contents of out-of-bounds files from the repo-server. The malicious payload would reference an out-of-bounds file, and the contents of that file would be returned as part of the response. Contents from a non-YAML file may be returned as part of an error message. The attacker would have to know or guess the location of the target file. Sensitive files which could be leaked include files from other Applications' source repositories or any secrets which have been mounted as files on the repo-server. This vulnerability is patched in Argo CD versions 2.1.11, 2.2.6, and 2.3.0. The patches prevent path traversal and limit access to users who either A) have been granted Application create privileges or B) have been granted Application get privileges and are requesting details for a repourl that has already been used for the given Application. There are currently no known workarounds.

Impact

All unpatched versions of Argo CD starting with v1.5.0 are vulnerable to a path traversal vulnerability allowing a malicious user with read/write access to leak sensitive files from Argo CD's repo-server.

A malicious Argo CD user who has been granted create or update access to Applications can leak the contents of any text file on the repo-server. By crafting a malicious Helm chart and using it in an Application, the attacker can retrieve the sensitive file's contents either as part of the generated manifests or in an error message. The attacker would have to know or guess the location of the target file.

Sensitive files which could be leaked include files from other Application's source repositories (potentially decrypted files, if you are using a decryption plugin) or any secrets which have been mounted as files on the repo-server.

Patches

A patch for this vulnerability has been released in the following Argo CD versions:

v2.3.0 v2.2.6 v2.1.11

Workarounds

The only certain way to avoid the vulnerability is to upgrade.

To mitigate the problem, you can avoid storing secrets in git avoid mounting secrets as files on the repo-server avoid decrypting secrets into files on the repo-server carefully limit who can create or update Applications

References

Security documentation for the repo-server component Argo CD RBAC configuration documentation

For more information

Open an issue in the Argo CD issue tracker or discussions Join us on Slack in channel #argo-cd