Pierluigi Paganini June 11, 2019

Security researchers at Alert Logic have discovered a vulnerability in the WordPress Live Chat plugin that could be exploited to steal and hijack sessions.

Experts at Alert Logic have discovered a vulnerability in the popular WordPress Live Chat plugin that could be exploited by an unauthorized remote attacker to steal chat logs or manipulate chat sessions.

The critical vulnerability, tracked as CVE-2019-12498, is a critical authentication bypass issue (CWE-287 / OWASP Top 10: A2: 2017-Broken Authentication) that affects version 8.0.32 and earlier of the plugin. 

The vulnerability is caused by the improper validation check for authentication, the attacker can trigger it to access restricted REST API endpoints.

“we uncovered a critical authentication bypass (CWE-287 / OWASP Top 10: A2: 2017-Broken Authentication) in version 8.0.32 and earlier.” reads the security advisory published by the experts. “This bypass allows an attacker to gain access to the REST API functionality without valid credentials—enabling exfiltration of chat logs and the ability to manipulate chat sessions.”

WP Live Chat Support provides customer support and chat with visitors through their WordPress websites, over 50,000 businesses currently use this plugin.

“The restricted REST API endpoints of the affected versions of WP Live Chat are vulnerable to abuse by unauthenticated remote attackers due to a flaw in the ‘wplc_api_permission_check()’ function.” continues the advisory.

The REST API endpoints of unpatched WP Live Chat Support installs are potentially exposed to attacks carried out by unauthenticated remote attackers due to vulnerability in the ‘wplc_api_permission_check()’ function.”  

“The above series of ‘register_rest_route()’ calls define those REST API endpoints which should have access restrictions due to the nature of the functionality they expose,” continues the Alert Logic research team.

“Each restricted endpoint shares the same ‘permission_callback’ function, namely the ‘wplc_api_permission_check()’ function which will be explored shortly.”

A remote attacker can exploit exposed endpoints for several malicious purposes, including:

• stealing the entire chat history for all chat sessions,
• modifying or deleting the chat history,
• injecting messages into an active chat session, posing as a customer support agent,
• forcefully ending active chat sessions, as part of a denial of service (DoS) attack.

Below the timeline of the vulnerability:

Fortunately, experts are not are of attacks in the wild exploiting the vulnerability.

Pierluigi Paganini

(SecurityAffairs – WordPress Live Chat plugin, hacking)

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