CVE-2016-4851 in Simple Chat
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Let's PHP! simple chat before 2016-08-15 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2016-4851 represents a cross-site scripting flaw within the Let's PHP! simple chat application, a web-based communication tool designed for basic messaging functionality. This vulnerability existed prior to the specified date of 2016-08-15 and demonstrates a classic weakness in web application input validation and output sanitization mechanisms. The affected system allowed malicious actors to inject arbitrary web scripts or HTML content through unspecified attack vectors, creating a significant security risk for users interacting with the chat platform. Such vulnerabilities typically arise when applications fail to properly validate or escape user-supplied data before rendering it within web pages, creating opportunities for attackers to execute malicious code in the context of other users' browsers.
The technical nature of this XSS vulnerability places it within the scope of CWE-79, which specifically addresses Cross-site Scripting flaws in web applications. This classification indicates that the vulnerability stems from insufficient input validation and output encoding practices, where user-provided content is directly incorporated into web responses without proper sanitization. The unspecified vectors suggest that the attack could potentially occur through multiple entry points within the chat application's interface, including message fields, user names, or other interactive elements. This broad attack surface increases the exploitability of the vulnerability and makes it more challenging to secure comprehensively.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it enables attackers to execute arbitrary code within the browser contexts of other users. This capability allows for session hijacking, credential theft, redirection to malicious sites, and potential privilege escalation within the chat environment. Users who interact with the vulnerable chat system become unwitting participants in attacks that can compromise their browser sessions and potentially lead to broader system compromises. The vulnerability particularly affects collaborative environments where multiple users share the same chat platform, as a single malicious injection can impact all connected participants.
Mitigation strategies for CVE-2016-4851 should focus on implementing robust input validation and output encoding mechanisms throughout the application. The recommended approach includes sanitizing all user-supplied input before processing and rendering it within web pages, employing proper HTML escaping techniques, and implementing Content Security Policy headers to limit script execution. Organizations should also consider implementing input length limits, regular security code reviews, and automated vulnerability scanning to prevent similar issues. Additionally, the vulnerability aligns with ATT&CK technique T1566, which covers social engineering tactics that leverage web-based vulnerabilities, highlighting the importance of both technical and user education approaches to security. The remediation process should involve immediate patching of the affected application, thorough testing of input validation mechanisms, and implementation of comprehensive logging to detect potential exploitation attempts.