A race condition in the nginx module in Phusion Passenger 3.x through 5.x before 5.3.2 allows local escalation of privileges when a non-standard passenger_instance_registry_dir with insufficiently strict permissions is configured. Replacing a file with a symlink after the file was created, but before it was chowned, leads to the target of the link being chowned via the path. Targeting sensitive files such as root's crontab file allows privilege escalation.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2018-12029 from the MITRE CVE dictionary dictionary and NIST NVD.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 7.8 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity Impact | High |
| Availability Impact | High |
| Platform | Package | State |
|---|---|---|
| Red Hat Satellite 6 | rubygem-passenger | Not affected |
| Red Hat Ceph Storage 1.3 | rubygem-passenger | Will not fix |
Vulmon