WordPress Download Manager < 3.1.19 - Arbitrary File Upload

2021-04-30 00:00

Strategic Overview

Status: Patched in 3.1.19
Affected Plugin: Download Manager
Affected Version: < 3.1.19
CVSS: 8.8High
Weakness type: CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE: CVE pending

View all Download Manager vulnerabilities

At a glance

This record tracks a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Download Manager WordPress plugin, affecting versions < 3.1.19. 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 3.1.19; sites on affected versions should update now. Disclosed April 2021, reported by WPScanTeam.

Vulnerability Overview

The WordPress Download Manager plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the wpdm_admin_upload_file function in versions before 3.1.19. Dangerous extensions such as .php4 are not restricted. This makes it possible for authenticated attackers with Author-level privileges and above to upload arbitrary files on the affected sites server which may make remote code execution possible.

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

Reaching this weakness in Download Manager < 3.1.19 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 Download Manager the fix is 3.1.19: builds < 3.1.19 are affected, anything from 3.1.19 onward is not.

Remediation

Update to version 3.1.19, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Download Manager: 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: Download Manager 3.1.19 closes this, and updating the plugin is the step that ends it.

Firewall
Scanner
Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/ed40b874-68e2-49f3-95b0-653600394e78

Related records

Same weakness class

7.5CVE-2021-34639: WordPress Download Manager <= 3.1.24 File UploadCVE-2021-34639

Other vulnerabilities in Download Manager

CVSS Vector

8.8

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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