CVE-2018-20150 in WordPress
Summary
by MITRE
In WordPress versions before 5.0.1, crafted URLs could trigger XSS for certain use cases involving plugins.
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Analysis
by VulDB Data Team • 06/19/2023
WordPress versions prior to 5.0.1 contained a cross-site scripting vulnerability that emerged from improper input validation and output escaping mechanisms within the core application. This flaw specifically manifested when processing crafted URLs that contained malicious script payloads, allowing attackers to inject executable code into web pages viewed by other users. The vulnerability exploited weaknesses in how WordPress handled URL parameters and plugin integration, creating a pathway for persistent XSS attacks that could compromise user sessions and execute unauthorized commands.
The technical implementation of this vulnerability stemmed from insufficient sanitization of user-supplied input within URL parsing functions. When WordPress encountered malformed or specially crafted URLs, the application failed to properly escape or validate the parameters before rendering them in web responses. This weakness was particularly pronounced in plugin environments where additional attack vectors existed due to the complex interaction between core WordPress functionality and third-party extensions. The flaw allowed attackers to inject malicious JavaScript code that would execute in the context of other users' browsers, potentially leading to session hijacking, data theft, or further exploitation of the compromised systems.
The operational impact of this vulnerability extended beyond simple script injection, as it could enable attackers to establish persistent footholds within WordPress installations. Users with administrative privileges were particularly at risk, as the XSS could be leveraged to escalate privileges or gain unauthorized access to sensitive administrative functions. The vulnerability's exploitation required minimal user interaction, often only involving the viewing of a maliciously crafted URL, making it particularly dangerous in environments where users frequently clicked on links from external sources. This made the vulnerability especially concerning for organizations relying on WordPress for content management, as it could affect thousands of users simultaneously through a single malicious link.
Mitigation strategies for this vulnerability centered on immediate patching of WordPress installations to version 5.0.1 or later, which contained the necessary input validation and output escaping improvements. Organizations should also implement comprehensive URL filtering mechanisms and monitor for suspicious URL patterns in their web application firewalls. The vulnerability aligns with CWE-79 Cross-site Scripting flaws and maps to ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, highlighting the need for robust input validation and output encoding practices. Security teams should also consider implementing Content Security Policy headers to limit the execution of unauthorized scripts and establish monitoring protocols to detect anomalous URL access patterns that might indicate exploitation attempts.