SB2020111904 - Arbitrary file upload in Backdrop CMS

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Main Vulnerability Database SB2020111904

SB2020111904 - Arbitrary file upload in Backdrop CMS

Published: November 19, 2020

Security Bulletin ID SB2020111904
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Arbitrary file upload (CVE-ID: CVE-2020-13671)

CWE-ID: CWE-434 - Unrestricted Upload of File with Dangerous Type

CVSSv4: 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


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

Remediation

Install update from vendor's website.

References