Versions of MCollective prior to 2.10.4 deserialized YAML from agents without calling safe_load, allowing the potential for arbitrary code execution on the server. The fix for this is to call YAML.safe_load on input. This has been tested in all Puppet-supplied MCollective plugins, but there is a chance that third-party plugins could rely on this insecure behavior.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mcollective | Puppet | * | 2.10.3 (including) |
| Mcollective | Ubuntu | artful | * |
| Mcollective | Ubuntu | bionic | * |
| Mcollective | Ubuntu | esm-apps/bionic | * |
| Mcollective | Ubuntu | esm-apps/xenial | * |
| Mcollective | Ubuntu | trusty | * |
| Mcollective | Ubuntu | upstream | * |
| Mcollective | Ubuntu | xenial | * |
| Mcollective | Ubuntu | yakkety | * |
| Mcollective | Ubuntu | zesty | * |
Potential Mitigations
- Make fields transient to protect them from deserialization.
- An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.