medium
6.3
CWE
362 59
Advisory Published
CVE Published
Updated

CVE-2012-0871: Race Condition

First published: Tue Feb 21 2012(Updated: )

Sebastian Krahmer of the SUSE Security Team reported that systemd-logind, a part of the systemd service and system manager, did not create certain special files in a secure way. systemd-logind is responsible for managing and tracking user login sessions, and if a user were to log into the X11 desktop, it creates entries in /run/user/[username]/X11, where /run/user/[username] is a user-owned directory. Because systemd-logind does not create the entries in a secure fashion, a malicious user could replace /run/user/[username]/X11 with a symlink to another root-owned directory, such as /etc/pam.d or /etc/cron.d. This would cause a symlink named "display" to be created in the target directory, which is a symlink to a user-owned file (/tmp/.X11-unix/X0). Using further attack vectors and this symlink, the malicious user could obtain a root shell, if he could beat two separate race conditions. Acknowledgements: Red Hat would like to thank Sebastian Krahmer of the SUSE Security Team for reporting this issue.

Credit: secalert@redhat.com

Affected SoftwareAffected VersionHow to fix
systemd<=037
systemd=1
systemd=2
systemd=3
systemd=4
systemd=5
systemd=6
systemd=7
systemd=8
systemd=9
systemd=10
systemd=11
systemd=12
systemd=13
systemd=14
systemd=15
systemd=16
systemd=17
systemd=18
systemd=19
systemd=20
systemd=21
systemd=22
systemd=23
systemd=24
systemd=25
systemd=26
systemd=27
systemd=28
systemd=29
systemd=30
systemd=31
systemd=32
systemd=33
systemd=34
systemd=35
systemd=36
SUSE Linux=12.1
openSUSE=12.1

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2012-0871?

    CVE-2012-0871 is classified as a medium severity vulnerability.

  • How do I fix CVE-2012-0871?

    To fix CVE-2012-0871, update systemd to a version later than 37 which contains the security fix.

  • What software versions are affected by CVE-2012-0871?

    CVE-2012-0871 affects systemd versions up to and including 37.

  • What type of vulnerability is CVE-2012-0871?

    CVE-2012-0871 is a security vulnerability related to improper file permissions in systemd-logind.

  • Who reported CVE-2012-0871?

    CVE-2012-0871 was reported by Sebastian Krahmer of the SUSE Security Team.

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