FunCaptcha – Anti-Spam CAPTCHA < 0.3.3 - Cross-Site Request Forgery

2014-04-11 00:00
Anonymous

Strategic Overview

Status
Patched in 0.3.3
Affected Version
< 0.3.3
CVSS
8.8High
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE pending
View all FunCaptcha – Anti-Spam CAPTCHA vulnerabilities

At a glance

This record tracks a high-severity Cross-Site Request Forgery (CSRF) vulnerability in the FunCaptcha WordPress plugin, affecting versions < 0.3.3. 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 0.3.3; sites on affected versions should update now. Disclosed April 2014.

Vulnerability Overview

The FunCaptcha – Anti-Spam CAPTCHA plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions before 0.3.3. This is due to missing or incorrect nonce validation on the funcaptcha_get_settings_post function. This makes it possible for unauthenticated attackers to manipulate plugin settings 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)

Reaching this weakness in FunCaptcha < 0.3.3 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 FunCaptcha the fix is 0.3.3: builds < 0.3.3 are affected, anything from 0.3.3 onward is not.

Remediation

Update to version 0.3.3, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to FunCaptcha: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: FunCaptcha 0.3.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

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