#VU48540 Arbitrary file upload in Drupal - CVE-2020-13671

Vulnerability identifier: #VU48540

Vulnerability risk: High

CVSSv4.0: 9.3 [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: Network

Exploit availability: No

Vulnerable software:
Drupal
Web applications / CMS

Vendor: Drupal

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

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Drupal: 7.x-dev - 7.73, 8.0 - 8.0.6, 8.1.0 beta1 - 8.1.10, 8.2.0 beta1 - 8.2.8, 8.3.0 alpha1 - 8.3.9, 8.4.0 alpha1 - 8.4.8, 8.5.0 alpha1 - 8.5.15, 8.6.0 alpha1 - 8.6.18, 8.7.0 rc1 - 8.7.14, 8.8.0 alpha1 - 8.8.10, 8.9.0 rc1 - 8.9.8, 9.0.0 beta1 - 9.0.7

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External links
https://www.drupal.org/sa-core-2020-012

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.