YARPP – Yet Another Related Posts Plugin < 4.2.5 - Cross-Site Request Forgery

2015-05-08 00:00
Evex

Strategic Overview

Status
Patched in 4.2.5
Affected Plugin
YARPP – Yet Another Related Posts Plugin
Affected Version
< 4.2.5
CVSS
9.8Critical
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE pending
View all YARPP – Yet Another Related Posts Plugin vulnerabilities

At a glance

This record tracks a critical-severity Cross-Site Request Forgery (CSRF) vulnerability in the YARPP WordPress plugin, affecting versions < 4.2.5. 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 4.2.5; sites on affected versions should update now. Disclosed May 2015, reported by Evex.

Vulnerability Overview

The YARPP – Yet Another Related Posts Plugin for WordPress is vulnerable a Cross-Site Request Forgery which can lead to Remote Code Execution in versions up to, and including, 4.2.4 via the yarpp_options.php file. This allows unauthenticated attackers to execute code on the server if they can successfully trick an 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, and no interaction from a victim user. 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 YARPP < 4.2.5 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 YARPP the fix is 4.2.5: builds < 4.2.5 are affected, anything from 4.2.5 onward is not.

Remediation

Update to version 4.2.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to YARPP: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: YARPP 4.2.5 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/78759abf-4584-4beb-9ae7-39a5c3fe4b75

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