CVE-2018-7169
An issue was discovered in shadow 4.5. newgidmap (in shadow-utils) is setuid and allows an unprivileged user to be placed in a user namespace where setgroups(2) is permitted.
Does this matter?
Lower severity and a low EPSS score (1.57%). Track it; it rarely justifies an emergency change on its own.
Description
An issue was discovered in shadow 4.5. newgidmap (in shadow-utils) is setuid and allows an unprivileged user to be placed in a user namespace where setgroups(2) is permitted. This allows an attacker to remove themselves from a supplementary group, which may allow access to certain filesystem paths if the administrator has used "group blacklisting" (e.g., chmod g-rwx) to restrict access to paths. This flaw effectively reverts a security feature in the kernel (in particular, the /proc/self/setgroups knob) to prevent this sort of privilege escalation.
- CVSS 3.0
- 5.3 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- EPSS
- 1.57% probability · 74th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-732
- Affected
- shadow project/shadow
- Source
- cve@mitre.org
References
- https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/1729357Exploit, Issue Tracking, Third Party Advisory
- https://security.gentoo.org/glsa/201805-09Third Party Advisory
- https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/1729357Exploit, Issue Tracking, Third Party Advisory
- https://security.gentoo.org/glsa/201805-09Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.