CVE-2017-15131

Publication date 9 January 2018

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

It was found that system umask policy is not being honored when creating XDG user directories, since Xsession sources xdg-user-dirs.sh before setting umask policy. This only affects xdg-user-dirs before 0.15.5 as shipped with Red Hat Enterprise Linux.

Read the notes from the security team

Status

Package Ubuntu Release Status
xdg-user-dirs 24.10 oracular
Not affected
24.04 LTS noble
Not affected
23.10 mantic
Not affected
23.04 lunar
Not affected
22.10 kinetic
Not affected
22.04 LTS jammy
Needs evaluation
21.10 impish
Not affected
21.04 hirsute Ignored end of life
20.10 groovy Ignored end of life
20.04 LTS focal
Not affected
19.10 eoan Ignored end of life
19.04 disco Ignored end of life
18.10 cosmic Ignored end of life
18.04 LTS bionic
Not affected
17.10 artful Ignored end of life
17.04 zesty Ignored end of life
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

Notes

seth-arnold

This feels like a fundamental misunderstanding of Unix model to assume that every task run on behalf of a user will be started as a child process of bash or sh run as an interactive or login shell. Environments that want a specific umask set for users should use the pam_umask(8) module as part of the login process. Environments that need a specific umask set for compliance reasons should investigate the feasibility of preparing a single-purpose LSM or seccomp jail interface of some sort.

rodrigo-zaiden

pam_umask is being used to set umask when an interactive session is started, so Ubuntu is not affected by this CVE.

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H