External Media <= 1.0.36 - Authenticated(Author+) File Upload to Stored Cross-Site Scripting via SVG

2023-03-30 00:00
Anonymous

Strategic Overview

Status
Unpatched
Affected Plugin
External Media
Affected Version
<= 1.0.36
CVSS
6.4Medium
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE pending
View all External Media vulnerabilities

At a glance

This record tracks a medium-severity Unrestricted Upload of File with Dangerous Type vulnerability in the External Media WordPress plugin, affecting versions <= 1.0.36. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Author level or above. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed March 2023.

Vulnerability Overview

The External Media plugin for WordPress is vulnerable to File Upload due to insufficient file type validation in the isUnsafe function in versions up to, and including, 1.0.36. This makes it possible for authenticated attackers with the upload_files capability, such as authors, to upload dangerous file types such as unsanitized SVG files which can lead to Cross-Site Scripting.

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 interaction from a victim user.

CWE-434: Unrestricted Upload of File with Dangerous Type

Reaching this weakness in External Media <= 1.0.36 takes an account at Author level or above. 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. No fixed build of this plugin is recorded for External Media yet, so installs running <= 1.0.36 stay exposed until the vendor ships one.

Remediation

No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.

How does WordSec protect against this?

An attacker needs Author access first, so the firewall sees the attempt as traffic from a logged-in account: 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. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.

  • Firewall
  • Scanner
  • Alerts

External References

Related records

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