CVE-2020-36847

Simple File List < 4.2.3 - Remote Code Execution

2020-11-02 00:00
coiffeur

Strategic Overview

Status
Patched in 4.2.3
Affected Plugin
Simple File List
Affected Version
< 4.2.3
CVSS
9.8Critical
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE-2020-36847
View all Simple File List vulnerabilities

At a glance

CVE-2020-36847 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Simple File List WordPress plugin, affecting versions < 4.2.3. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 4.2.3; sites on affected versions should update now. Disclosed November 2020, reported by coiffeur.

Vulnerability Overview

The Simple-File-List Plugin for WordPress is vulnerable to Remote Code Execution in versions up to, and including, 4.2.2 via the rename function which can be used to rename uploaded PHP code with a png extension to use a php extension. This allows unauthenticated attackers to execute code on the server.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-434: Unrestricted Upload of File with Dangerous Type

Reaching this weakness in Simple File List < 4.2.3 takes a caller who can reach the endpoint. An unrestricted file upload lets a caller store a file whose type or destination the application does not properly constrain.

If an uploaded file lands anywhere the server will execute, the flaw becomes remote code execution and the site should be treated as fully compromised. For Simple File List the fix is 4.2.3: builds < 4.2.3 are affected, anything from 4.2.3 onward is not.

Remediation

Update to version 4.2.3, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Simple File List: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Simple File List 4.2.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-36847https://www.wordfence.com/threat-intel/vulnerabilities/id/9eb835fd-6ebf-4162-856c-0366b663a07ehttps://nvd.nist.gov/vuln/detail/CVE-2020-36847

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C