CVE-2021-4365

Frontend File Manager <= 18.2 - Unauthenticated Stored Cross-Site Scripting

2021-07-12 00:00
Jerome Bruandet

Strategic Overview

Status
Patched in 18.3
Affected Plugin
Frontend File Manager Plugin
Affected Version
< 18.3
CVSS
7.2High
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2021-4365
View all Frontend File Manager Plugin vulnerabilities

At a glance

CVE-2021-4365 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Frontend File Manager Plugin WordPress plugin, affecting versions < 18.3. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 18.3; sites on affected versions should update now. Disclosed July 2021, reported by Jerome Bruandet.

Vulnerability Overview

The Frontend File Manager plugin for WordPress is vulnerable to Unauthenticated Stored Cross-Site Scripting in versions up to, and including, 18.2. This is due to lacking authentication protections and santisation all on the wpfm_edit_file_title_desc AJAX action. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

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.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Frontend File Manager Plugin < 18.3 takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Frontend File Manager Plugin the fix is 18.3: builds < 18.3 are affected, anything from 18.3 onward is not.

Remediation

Update to version 18.3, 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. None of that substitutes for the fix: Frontend File Manager Plugin 18.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-4365https://www.wordfence.com/threat-intel/vulnerabilities/id/a9c82154-d390-44ba-a54a-89f4bb69cdcehttps://nvd.nist.gov/vuln/detail/CVE-2021-4365

Related records

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