melange allows users to build apk packages using declarative pipelines. Starting in version 0.23.0 and prior to version 0.29.5, SBOM files generated by melange in apks had file system permissions mode 666. This potentially allows an unprivileged user to tamper with apk SBOMs on a running image, potentially confusing security scanners. An attacker could also perform a DoS under special circumstances. Version 0.29.5 fixes the issue.
Weakness
During installation, installed file permissions are set to allow anyone to modify those files.
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
References