CVE Vulnerabilities

CVE-2019-19191

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

Published: Nov 21, 2019 | Modified: Jan 14, 2020
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

Shibboleth Service Provider (SP) 3.x before 3.1.0 shipped a spec file that calls chown on files in a directory controlled by the service user (the shibd account) after installation. This allows the user to escalate to root by pointing symlinks to files such as /etc/shadow.

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
Service_provider Shibboleth 3.0.0 (including) 3.1.0 (excluding)

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