Simple Calendar <= 3.1.42 - Cross-Site Request Forgery to Transient Cache Clearing

2023-05-11 00:00
Anonymous

Strategic Overview

Status
Patched in 3.1.43
Affected Plugin
Simple Calendar – Google Calendar Plugin
Affected Version
<= 3.1.42
CVSS
4.3Medium
Weakness type
CWE-352 · Cross-Site Request Forgery (CSRF)
CVE
CVE pending
View all Simple Calendar – Google Calendar Plugin vulnerabilities

At a glance

This record tracks a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the Simple Calendar WordPress plugin, affecting versions <= 3.1.42. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.1.43; sites on affected versions should update now. Disclosed May 2023.

Vulnerability Overview

The Simple Calendar plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.1.42. This is due to missing nonce validation on the clear_cache() function used to clear the plugin's transients. This makes it possible for unauthenticated attackers to clear the plugin's transients for a given id, 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.

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

Simple Calendar <= 3.1.42 carries this weakness at clear_cache(), 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 Simple Calendar the fix is 3.1.43: builds <= 3.1.42 are affected, anything from 3.1.43 onward is not.

Remediation

Update to version 3.1.43, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Simple Calendar: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Simple Calendar 3.1.43 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/248b74d3-5228-473d-a79a-743566898606

Related records

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