CVE-2017-18078 Information

Description

systemd-tmpfiles in systemd before 237 attempts to support ownership/permission changes on hardlinked files even if the fs.protected_hardlinks sysctl is turned off which allows local users to bypass intended access restrictions via vectors involving a hard link to a file for which the user lacks write access as demonstrated by changing the ownership of the /etc/passwd file.

CVSS Vector

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

Reference

http://lists.opensuse.org/opensuse-updates/2018-02/msg00109.html http://packetstormsecurity.com/files/146184/systemd-Local-Privilege-Escalation.html http://www.openwall.com/lists/oss-security/2018/01/29/3 https://github.com/systemd/systemd/issues/7736 https://lists.debian.org/debian-lts-announce/2019/04/msg00022.html https://www.exploit-db.com/exploits/43935/ https://www.openwall.com/lists/oss-security/2018/01/29/4

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8