CVE-2019-20210 in CTHthemes CityBook Theme
Summary
by MITRE
The CTHthemes CityBook before 2.3.4, TownHub before 1.0.6, and EasyBook before 1.2.2 themes for WordPress allow Reflected XSS via a search query.
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Analysis
by VulDB Data Team • 03/20/2024
This vulnerability affects multiple WordPress themes including CTHthemes CityBook prior to version 2.3.4, TownHub prior to version 1.0.6, and EasyBook prior to version 1.2.2. The issue stems from improper input validation and output escaping mechanisms within the search functionality of these themes. When users perform search operations on websites utilizing these vulnerable themes, the search query parameters are not adequately sanitized before being reflected back to the user's browser. This creates a classic reflected cross-site scripting vulnerability that falls under CWE-79 which specifically addresses cross-site scripting flaws.
The technical implementation flaw occurs at the theme level where search results pages fail to properly escape or filter user-supplied input before rendering it in HTML output. Attackers can craft malicious search queries containing javascript code that gets executed in the victim's browser when the search results page is displayed. This vulnerability operates at the application layer and requires no authentication from the attacker, making it particularly dangerous as it can be exploited through social engineering or automated scanning tools. The attack vector follows the standard reflected XSS pattern where the malicious payload is embedded in a URL parameter and delivered through a search query.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to perform various malicious activities including session hijacking, credential theft, redirection to malicious sites, and data exfiltration. An attacker could craft a search query containing malicious javascript that would execute in the context of a logged-in administrator's browser, potentially leading to complete compromise of the WordPress site. This vulnerability also aligns with ATT&CK technique T1566 which covers social engineering through malicious links, as the vulnerability can be exploited through crafted search URLs that appear legitimate to end users.
Mitigation strategies for this vulnerability primarily involve updating to the patched versions of the affected themes as released by the vendors. Users should immediately upgrade to CTHthemes CityBook 2.3.4, TownHub 1.0.6, and EasyBook 1.2.2 or later versions that contain proper input validation and output escaping mechanisms. Additionally, administrators should implement content security policies to limit the execution of inline scripts and consider implementing web application firewalls to detect and block malicious search queries. The vulnerability demonstrates the importance of proper input validation and output encoding practices as recommended in OWASP Top Ten and ISO 27001 security standards. Regular security audits and penetration testing of WordPress installations can help identify similar vulnerabilities in custom themes or plugins that may not have been properly secured against cross-site scripting attacks.