Helm vulnerable to denial of service through through repository index file

Fuzz testing, by Ada Logics and sponsored by the CNCF, identified input to functions in the repo package that can cause a segmentation violation. Applications that use functions from the repo package in the Helm SDK can have a Denial of Service attack when they use this package and it panics.

Impact

The repo package contains a handler that processes the index file of a repository. For example, the Helm client adds references to chart repositories where charts are managed. The repo package parses the index file of the repository and loads it into structures Go can work with. Some index files can cause array data structures to be created causing a memory violation.

Applications that use the repo package in the Helm SDK to parse an index file can suffer a Denial of Service when that input causes a panic that cannot be recovered from.

The Helm Client will panic with an index file that causes a memory violation panic. Helm is not a long running service so the panic will not affect future uses of the Helm client.

Patches

This issue has been resolved in 3.10.3.

Workarounds

SDK users can validate index files that are correctly formatted before passing them to the repo functions.

For more information

Helm’s security policy is spelled out in detail in our SECURITY document.

Credits

Disclosed by Ada Logics in a fuzzing audit sponsored by CNCF.