CVE-2020-36701

Page Builder: KingComposer < 2.9.4 - Arbitrary File Upload

2020-06-15 00:00
Jerome Bruandet

Strategic Overview

Status
Patched in 2.9.4
Affected Version
<= 2.9.3
CVSS
8.8High
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE-2020-36701
View all Page Builder: KingComposer – Free Drag and Drop page builder by King-Theme vulnerabilities

At a glance

CVE-2020-36701 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Page Builder: KingComposer WordPress plugin, affecting versions <= 2.9.3. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). The issue is fixed in version 2.9.4; sites on affected versions should update now. Disclosed June 2020, reported by Jerome Bruandet.

Vulnerability Overview

The Page Builder: KingComposer plugin for WordPress is vulnerable to Arbitrary File Uploads in versions up to, and including, 2.9.3 via the 'process_bulk_action' function in the 'kingcomposer/includes/kc.extensions.php' file. This makes it possible for authenticated users with author level permissions and above to upload arbitrary files onto the server which can be used 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 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

Page Builder: KingComposer <= 2.9.3 carries this weakness at process_bulk_action, and reaching it 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 Page Builder: KingComposer the fix is 2.9.4: builds <= 2.9.3 are affected, anything from 2.9.4 onward is not.

Remediation

Update to version 2.9.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Page Builder: KingComposer: 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: Page Builder: KingComposer 2.9.4 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

Related records

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