Cortex's Alertmanager can expose local files content via specially crafted config

Impact

A local file inclusion vulnerability exists in Cortex versions v1.13.0, v1.13.1 and v1.14.0, where a malicious actor could remotely read local files as a result of parsing maliciously crafted Alertmanager configurations when submitted to the Alertmanager Set Configuration API. Only users of the Cortex Alertmanager service using -experimental.alertmanager.enable-api or enable_api: true are affected.

Specific Go Packages Affected

github.com/cortexproject/cortex/pkg/alertmanager

Patches

Affected Cortex users are advised to upgrade to versions 1.13.2 or 1.14.1.

Workarounds

Patching is ultimately advised. Using out-of-bound validation, Cortex administrators may reject Alertmanager configurations containing the api_key_file setting in the opsgenie_configs section and opsgenie_api_key_file in the global section before sending to the Set Alertmanager Configuration API as a workaround.

References

• Fixed Versions:
  • https://github.com/cortexproject/cortex/releases/tag/v1.14.1
  • https://github.com/cortexproject/cortex/releases/tag/v1.13.2
• https://cortexmetrics.io/docs/api/#set-alertmanager-configuration

For more information

If you have any questions or comments about this advisory:

• Open an issue in cortex
• Email us at [email protected].