CVE-2020-19962 in Chaoji
Summary
by MITRE • 10/14/2021
A stored cross-site scripting (XSS) vulnerability in the getClientIp function in /lib/tinwin.class.php of Chaoji CMS 2.39, allows attackers to execute arbitrary web scripts.
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Analysis
by VulDB Data Team • 10/20/2021
The stored cross-site scripting vulnerability identified as CVE-2020-19962 resides within the Chaoji CMS version 2.39, specifically in the getClientIp function located in the /lib/tinwin.class.php file. This vulnerability represents a critical security flaw that enables attackers to inject malicious scripts into web pages viewed by other users, fundamentally compromising the integrity of the content management system. The vulnerability manifests when user-supplied input containing malicious JavaScript code is not properly sanitized before being processed and stored within the system's database. When legitimate users access pages that display this stored content, their browsers execute the embedded scripts, creating a persistent threat vector that can affect multiple users over time. This particular weakness falls under the category of CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or validate user input before incorporating it into dynamically generated web content. The vulnerability demonstrates how insufficient input validation and output encoding can create persistent attack surfaces that persist beyond individual user sessions.
The technical exploitation of this vulnerability occurs through the manipulation of the getClientIp function, which is designed to retrieve and process client IP addresses for various system operations. When attackers craft malicious input that includes JavaScript code within IP address fields or related parameters, the function fails to adequately sanitize this data before storage. The stored data is then retrieved and displayed in web pages without proper HTML escaping or context-appropriate encoding, allowing the malicious scripts to execute in the browsers of unsuspecting users. This stored XSS attack vector is particularly dangerous because the malicious code remains persistent within the application's database, continuously affecting any user who accesses the affected pages. The vulnerability demonstrates a fundamental flaw in the application's data handling processes, where input validation occurs too late in the processing chain or not at all, allowing dangerous content to be stored and subsequently executed. The ATT&CK framework categorizes this as a form of code injection technique under the T1566.001 sub-technique, specifically targeting web applications through the manipulation of input fields that are subsequently rendered without proper sanitization.
The operational impact of CVE-2020-19962 extends beyond simple script execution, as attackers can leverage this vulnerability to perform various malicious activities including session hijacking, credential theft, and data exfiltration. Once an attacker successfully injects malicious scripts, they can potentially steal cookies, redirect users to phishing sites, or even modify content displayed on the website. The persistent nature of stored XSS means that the attack remains active for as long as the malicious content exists in the database, providing attackers with extended access windows. Organizations using Chaoji CMS 2.39 face significant risks including compromised user accounts, unauthorized data access, and potential reputational damage from successful attacks. The vulnerability also creates opportunities for attackers to establish backdoors or deploy additional malware through the executed scripts. The attack surface is further expanded because the vulnerability affects core functionality related to client IP address handling, which is likely used in various system operations including logging, access control, and user tracking mechanisms. This makes the exploitation potentially more widespread and impactful than initially apparent.
Mitigation strategies for CVE-2020-19962 should focus on implementing robust input validation and output encoding mechanisms throughout the application. Organizations must ensure that all user-supplied data, particularly input that is stored and later displayed, undergoes proper sanitization before being processed by the getClientIp function. The implementation of Content Security Policy headers can provide an additional layer of protection against script execution, while proper HTML escaping should be enforced for all dynamic content generation. Regular security audits and code reviews should specifically target input handling functions to identify similar vulnerabilities in other parts of the application. The most effective long-term solution involves upgrading to a patched version of Chaoji CMS that addresses this specific vulnerability through proper input validation and sanitization. Security teams should also implement monitoring systems to detect unusual patterns in IP address data that might indicate attempted exploitation. Additionally, network-level protections such as web application firewalls can help detect and block malicious payloads before they reach the vulnerable application components. The remediation process should include comprehensive testing to ensure that all input fields are properly validated and that stored data is appropriately escaped before rendering, addressing the root cause rather than merely patching symptoms of the vulnerability.