CVE-2023-28433: Minio Privilege Escalation on Windows via Path separator manipulation

Impact All users on Windows are impacted. MinIO fails to filter the \ character, which allows for arbitrary object placement across buckets. As a result, a user with low privileges, such as an access key, service account, or STS credential, which only has permission to PutObject in a specific bucket, can create an admin user.

Patches There are two patches that fix this problem comprehensively

commit b3c54ec81e0a06392abfb3a1ffcdc80c6fbf6ebc Author: Harshavardhana <harsha@minio.io> Date: Mon Mar 20 13:16:00 2023 -0700

reject object names with '\' on windows (#16856)

commit 8d6558b23649f613414c8527b58973fbdfa4d1b8 Author: Harshavardhana <harsha@minio.io> Date: Mon Mar 20 00:35:25 2023 -0700

fix: convert '\' to '/' on windows (#16852)

Workarounds There are no known workarounds

References The vulnerable code: go // minio/cmd/generic-handlers.go // Check if the incoming path has bad path components, // such as ".." and "." // SlashSeparator -> / // dotdotComponent -> .. // dotComponent -> . func hasBadPathComponent(path string) bool { path = strings.TrimSpace(path) for , p := range strings.Split(path, SlashSeparator) { switch strings.TrimSpace(p) { case dotdotComponent: return true case dotComponent: return true } } return false }