CVE Vulnerabilities

CVE-2018-19044

Improper Link Resolution Before File Access ('Link Following')

Published: Nov 08, 2018 | Modified: Aug 06, 2019
CVSS 3.x
4.7
MEDIUM
Source:
NVD
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS 2.x
3.3 LOW
AV:L/AC:M/Au:N/C:N/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

keepalived 2.0.8 didnt check for pathnames with symlinks when writing data to a temporary file upon a call to PrintData or PrintStats. This allowed local users to overwrite arbitrary files if fs.protected_symlinks is set to 0, as demonstrated by a symlink from /tmp/keepalived.data or /tmp/keepalived.stats to /etc/passwd.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Keepalived Keepalived 2.0.8 (including) 2.0.8 (including)

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References