CVE Vulnerabilities

CVE-2019-13915

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

Published: Jul 18, 2019 | Modified: Aug 24, 2020
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

b3log Wide before 1.6.0 allows three types of attacks to access arbitrary files. First, the attacker can write code in the editor, and compile and run it approximately three times to read an arbitrary file. Second, the attacker can create a symlink, and then place the symlink into a ZIP archive. An unzip operation leads to read access, and write access (depending on file permissions), to the symlink target. Third, the attacker can import a Git repository that contains a symlink, similarly leading to read and write access.

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
Wide B3log * 1.6.0 (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