CVE-2018-18955

 

Published at: - 16-11-2018 09:29

Last modified: - 26-10-2022 01:44

Total changes: - 2

Description

In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.

Common Vulnerability Scoring System (CVSS)

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

 

Verification logic

 

Reference

• https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19
• https://bugs.chromium.org/p/project-zero/issues/detail?id=1712
• http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
• 105941-Third Party Advisory, VDB Entry
• 45886-Exploit, Patch, Third Party Advisory, VDB Entry
• USN-3833-1-Third Party Advisory
• USN-3832-1-Third Party Advisory
• 45915-Exploit, Third Party Advisory, VDB Entry
• USN-3836-2-Third Party Advisory
• USN-3836-1-Third Party Advisory
• USN-3835-1-Third Party Advisory
• https://support.f5.com/csp/article/K39103040
• https://security.netapp.com/advisory/ntap-20190416-0003/

 

Keywords

NVD

 

CVE-2018-18955

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures