CVE-2007-3708 in CodeIgniter
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in CodeIgniter 1.5.3 before 20070626 allows remote attackers to inject arbitrary web script or HTML via (1) String.fromCharCode and (2) malformed nested tag manipulations in an unspecified component, related to insufficient sanitization by the xss_clean function.
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Analysis
by VulDB Data Team • 09/05/2018
The vulnerability described in CVE-2007-3708 represents a critical cross-site scripting flaw within the CodeIgniter web application framework version 1.5.3 and earlier. This vulnerability resides in the xss_clean function which is designed to sanitize user input and prevent malicious scripts from being executed in web applications. The flaw stems from inadequate sanitization mechanisms that fail to properly handle specific JavaScript encoding techniques and malformed HTML structures. Attackers can exploit this weakness by crafting malicious input that bypasses the security checks implemented by the framework's XSS protection system.
The technical implementation of this vulnerability leverages two primary exploitation vectors that demonstrate sophisticated bypass techniques against the framework's security measures. The first vector involves the use of String.fromCharCode JavaScript method, which allows attackers to construct malicious scripts without using traditional character literals that might be detected by simple pattern matching. The second vector exploits malformed nested tag manipulations that can confuse the sanitization logic and create opportunities for script injection. These techniques specifically target the xss_clean function's inability to properly parse and neutralize encoded JavaScript sequences and malformed HTML structures that appear legitimate to naive sanitization routines.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to execute arbitrary web scripts in the context of affected users' browsers. This capability allows for session hijacking, credential theft, defacement of web applications, and potential redirection to malicious sites. The vulnerability affects all applications built on CodeIgniter 1.5.3 or earlier versions that rely on the xss_clean function for input validation, potentially compromising thousands of web applications that were using this framework. The attack surface is particularly concerning because it targets fundamental input validation mechanisms that are critical to web application security.
Security professionals should understand that this vulnerability maps to CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a core weakness in web application security that directly leads to XSS vulnerabilities. The attack pattern aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as it leverages JavaScript execution capabilities to compromise web applications. Organizations using affected CodeIgniter versions should immediately apply the patch released on June 26, 2007, which addressed the insufficient sanitization logic. Additionally, implementing proper input validation at multiple layers, including client-side and server-side, along with regular security audits of framework components, can help prevent similar vulnerabilities from occurring in the future. The incident underscores the importance of thorough testing of security functions and the need for comprehensive sanitization routines that can handle sophisticated attack vectors.