CVE-2019-25138

User Submitted Posts <= 20190312 - Unauthenticated Arbitrary File Upload

2019-05-02 00:00
Jerome Bruandet

Strategic Overview

Status
Patched in 20190426
Affected Plugin
User Submitted Posts – Enable Users to Submit Posts from the Front End
Affected Version
< 20190426
CVSS
9.8Critical
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE-2019-25138
View all User Submitted Posts – Enable Users to Submit Posts from the Front End vulnerabilities

At a glance

CVE-2019-25138 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the User Submitted Posts WordPress plugin, affecting versions < 20190426. 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 20190426; sites on affected versions should update now. Disclosed May 2019, reported by Jerome Bruandet.

Vulnerability Overview

The User Submitted Posts plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the usp_check_images function in versions up to, and including, 20190312. This makes it possible for unauthenticated attackers 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 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 User Submitted Posts < 20190426 takes no account at all. 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 User Submitted Posts the fix is 20190426: builds < 20190426 are affected, anything from 20190426 onward is not.

Remediation

Update to version 20190426, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: 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: User Submitted Posts 20190426 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2019-25138https://www.wordfence.com/threat-intel/vulnerabilities/id/5a97877b-fb4d-4e87-bcff-56be65fee6cehttps://nvd.nist.gov/vuln/detail/CVE-2019-25138

Related records

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