CVE-2019-19133 in CSS Hero Plugin
Summary
by MITRE
The CSS Hero plugin through 4.0.3 for WordPress is prone to reflected XSS via the URI in a csshero_action=edit_page request because it fails to sufficiently sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary JavaScript in the browser of an unsuspecting user in the context of the affected site. This may allow the attacker to steal cookies or launch other attacks.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability identified as CVE-2019-19133 affects the CSS Hero plugin version 4.0.3 and earlier for WordPress platforms, representing a critical reflected cross-site scripting flaw that compromises user security. This vulnerability exists within the plugin's handling of the csshero_action=edit_page request parameter, where the application fails to adequately sanitize user-supplied input before processing it in the web response. The flaw enables attackers to inject malicious JavaScript code through carefully crafted URLs that contain the vulnerable parameter, making it particularly dangerous as it can be exploited through social engineering or by enticing users to click malicious links.
The technical implementation of this vulnerability stems from improper input validation and output encoding practices within the CSS Hero plugin's codebase. When the plugin processes the csshero_action=edit_page parameter, it directly incorporates user-provided data into the HTTP response without sufficient sanitization or encoding mechanisms. This creates an environment where malicious payloads can be executed within the browser context of authenticated users who visit the compromised page. The vulnerability specifically aligns with CWE-79 which defines Cross-Site Scripting as a weakness that allows attackers to inject client-side scripts into web applications. The reflected nature of the vulnerability means that the malicious script is reflected off the web server and executed in the victim's browser, making it particularly effective for phishing attacks and session hijacking.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities within the context of the compromised WordPress site. An attacker could potentially steal session cookies, gain unauthorized access to administrator accounts, or manipulate the content displayed to users. The vulnerability is particularly concerning because it affects the WordPress plugin ecosystem, which is widely used across the internet, and allows attackers to leverage the trust relationship between users and the WordPress platform. This vulnerability can be exploited through various attack vectors including email phishing campaigns, compromised websites, or social media platforms where users might be directed to malicious URLs containing the exploit payload.
The exploitation of this vulnerability aligns with several tactics outlined in the MITRE ATT&CK framework, particularly those related to initial access and execution phases of cyber attacks. Attackers can use this vulnerability as part of a broader attack chain to establish persistent access to WordPress installations, potentially leading to complete system compromise. The vulnerability demonstrates a failure in the principle of least privilege and proper input validation, as the plugin does not implement adequate security measures to prevent malicious data from being processed and executed within the user's browser context. Organizations using the affected plugin version should immediately implement mitigations including updating to the patched version, implementing web application firewalls, and conducting security audits of their WordPress installations to identify similar vulnerabilities. Additionally, administrators should consider implementing Content Security Policy headers to provide an additional layer of protection against reflected XSS attacks and other client-side exploits.
The broader implications of this vulnerability highlight the importance of regular security updates and proper input validation practices in web application development. WordPress plugin developers must implement robust sanitization and encoding mechanisms to prevent XSS vulnerabilities, particularly in areas where user input is directly incorporated into web responses. The vulnerability also underscores the need for comprehensive security testing including dynamic application security testing and manual code review processes to identify and remediate such flaws before they can be exploited in the wild. Organizations should maintain updated vulnerability management processes that include monitoring for CVEs affecting their web applications and implementing timely patches to protect against known security flaws.