Headline
GHSA-x6ph-r535-3vjw: apko is vulnerable to attack through incorrect permissions in /etc/ld.so.cache and other files
It was discovered that the ld.so.cache in images generated by apko had file system permissions mode 0666:
bash-5.3# find / -type f -perm -o+w
/etc/ld.so.cache
This issue was introduced in commit 04f37e2 ("generate /etc/ld.so.cache (#1629)")(v0.27.0).
Impact
This potentially allows a local unprivileged user to add additional additional directories including dynamic libraries to the dynamic loader path. A user could exploit this by placing a malicious library in a directory they control.
Patches
This issue was addressed in apko in aedb077 ("fix: /etc/ld.so.cache file permissions (#1758)") (v0.29.5).
Acknowledgements
Many thanks to Cody Harris from H2O.ai for reporting this issue.
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.