Booking Calendar <= 6.2 - Cross-Site Request Forgery leading to Cross-Site Scripting

2016-08-01 00:00
Edwin Molenaar

Strategic Overview

Status
Patched in 6.2.1
Affected Plugin
Booking Calendar
Affected Version
< 6.2.1
CVSS
8.8High
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE pending
View all Booking Calendar vulnerabilities

At a glance

This record tracks a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Booking Calendar WordPress plugin, affecting versions < 6.2.1. 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 6.2.1; sites on affected versions should update now. Disclosed August 2016, reported by Edwin Molenaar.

Vulnerability Overview

The Booking Calendar plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 6.2. This is due to missing or incorrect nonce validation in the plugin's Import tab. This makes it possible for unauthenticated attackers to to inject arbitrary web scripts that execute in a victim's browser via 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-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Booking Calendar < 6.2.1 takes a caller who can reach the endpoint. 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 Booking Calendar the fix is 6.2.1: builds < 6.2.1 are affected, anything from 6.2.1 onward is not.

Remediation

Update to version 6.2.1, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Booking Calendar: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Booking Calendar 6.2.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/6f36d866-aa94-478b-8b62-0906bc95e413

Related records

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