Arbitrary file upload in Drupal - CVE-2020-13671
Published: November 18, 2020 / Updated: February 20, 2022
Vulnerability identifier: #VU48540
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber
CVE-ID: CVE-2020-13671
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: Drupal
Affected software:
Drupal
Drupal
Detailed vulnerability description
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to insufficient validation of file during file upload. A remote attacker can upload a malicious PHP file and execute it on the server.
Additionally, it's recommended that you audit all previously uploaded
files to check for malicious extensions. Look specifically for files
that include more than one extension, like .php.txt or .html.gif.
Pay specific attention to the following file extensions, which should
be considered dangerous even when followed by another extension:
- phar
- php
- pl
- py
- cgi
- asp
- js
- html
- htm
How to mitigate CVE-2020-13671
Install updates from vendor's website.