Skip to content

Path Traversal Vulnerability in `LESS` Parser allows reading of sensitive server files

Moderate
SychO9 published GHSA-vhm8-wwrf-3gcw Mar 10, 2023

Package

composer flarum/core (Composer)

Affected versions

< 1.6.3

Patched versions

1.7.0

Description

Impact

If an admin account has already been compromised by an attacker, the LESS parser can be exploited to read sensitive files on the server through the use of path traversal techniques.

An attacker can achieve this by providing an absolute path to a sensitive file in the custom LESS setting, which the LESS parser will then read. For example, an attacker could use the following code to read the contents of the /etc/passwd file:

@import (inline) '/etc/passwd';

.test {
  content: data-uri('/etc/passwd');
}

Patches

The vulnerability has been addressed in version 1.7. Users should upgrade to this version to mitigate the vulnerability.

Workarounds

Users can mitigate the vulnerability by ensuring that their admin accounts are secured with strong passwords and other best practices for account security. Additionally, users can limit the exposure of sensitive files on the server by implementing appropriate file permissions and access controls.

Severity

Moderate
6.5
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H

CVE ID

CVE-2023-27577

Weaknesses