CVE-2021-24705

NEX-Forms – Ultimate Form Builder <= 8.4.2 - Cross-Site Request Forgery to Cross-Site Scripting

2021-11-14 00:00
Shivam Rai

Strategic Overview

Status
Patched in 8.4.3
Affected Plugin
NEX-Forms – Ultimate Forms Plugin for WordPress
Affected Version
<= 8.4.2
CVSS
8.8High
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE-2021-24705
View all NEX-Forms – Ultimate Forms Plugin for WordPress vulnerabilities

At a glance

CVE-2021-24705 is a high-severity Cross-Site Request Forgery (CSRF) vulnerability in the NEX-Forms WordPress plugin, affecting versions <= 8.4.2. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 8.4.3; sites on affected versions should update now. Disclosed November 2021, reported by Shivam Rai.

Vulnerability Overview

The NEX-Forms plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 8.4.2. This is due to missing or incorrect nonce validation on the update_record() function, in addition to many other functions. This makes it possible for unauthenticated attackers to modify the plugin's settings and inject malicious JavaScripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

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. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-352: Cross-Site Request Forgery (CSRF)

NEX-Forms <= 8.4.2 carries this weakness at update_record(), and reaching it takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.

An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For NEX-Forms the fix is 8.4.3: builds <= 8.4.2 are affected, anything from 8.4.3 onward is not.

Remediation

Update to version 8.4.3, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to NEX-Forms: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: NEX-Forms 8.4.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24705https://www.wordfence.com/threat-intel/vulnerabilities/id/8a7b4d0b-9845-4d0b-b255-a311076f5ca7https://nvd.nist.gov/vuln/detail/CVE-2021-24705

Related records

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