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Ubuntu: USN-5254-1 (CVE-2018-7169): shadow vulnerabilities

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Ubuntu: USN-5254-1 (CVE-2018-7169): shadow vulnerabilities

Severity
5
CVSS
(AV:N/AC:L/Au:N/C:P/I:N/A:N)
Published
02/15/2018
Created
02/01/2022
Added
01/28/2022
Modified
03/22/2023

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.

Solution(s)

  • ubuntu-upgrade-login
  • ubuntu-upgrade-passwd
  • ubuntu-upgrade-uidmap

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