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');
}
The vulnerability has been addressed in version 1.7. Users should upgrade to this version to mitigate the vulnerability.
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.
| Score | Percentile |
|---|---|
| 0.33% | 55.75% |
| Base score | Version | Severity | Vector |
|---|---|---|---|
| 6.5 | 3.1 | — |
|
| Type | Value |
|---|---|
| GHSA | GHSA-vhm8-wwrf-3gcw ↗ |
| CVE | CVE-2023-27577 ↗ |
| CWE id | Name |
|---|---|
| CWE-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') |
Vulnerable version ranges and first patched releases as published by GitHub.
| Ecosystem | Package | Vulnerable range | First patched | Vulnerable functions |
|---|---|---|---|---|
| composer | flarum/core | < 1.7.0 | 1.7.0 | — |