CVE-2007-3484 in Custom Search Engine
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in search.php in Google Custom Search Engine allows remote attackers to inject arbitrary web script or HTML via the q parameter. NOTE: this issue is disputed by the Google Security Team, who states that "Google does not provide the 'search.php' script referenced. When a user creates a custom search engine, we provide them with a block of javascript to include on their site. Some users write additional code around this block of javascript to further customize their website.
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Analysis
by VulDB Data Team • 07/03/2024
The vulnerability described in CVE-2007-3484 represents a classic cross-site scripting flaw that could potentially allow remote attackers to execute malicious scripts within the context of a user's browser session. This particular issue was reported to affect the search.php component of Google Custom Search Engine implementations, specifically targeting the q parameter which handles search queries. The vulnerability classification aligns with CWE-79 which defines cross-site scripting as a weakness where untrusted data is incorporated into web page content without proper validation or encoding, creating opportunities for attackers to inject malicious code.
The technical exploitation of this vulnerability would occur when an attacker crafts a malicious URL containing script code within the q parameter of the search.php endpoint. When a victim accesses such a crafted link, the malicious script would execute in the victim's browser context, potentially leading to session hijacking, data theft, or redirection to malicious sites. This type of attack directly violates the principle of input validation and demonstrates the critical importance of sanitizing all user-provided data before incorporating it into web responses. The vulnerability operates at the application layer and could be classified under ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
However, the Google Security Team has disputed this vulnerability report, asserting that the specific search.php script referenced in the CVE does not exist within Google's official Custom Search Engine implementation. Their explanation indicates that when users create custom search engines, Google provides JavaScript code blocks for integration into websites rather than providing server-side scripts like search.php. This clarification suggests that any implementation of the vulnerability may have been due to third-party modifications or custom code added by users around Google's provided JavaScript components, rather than being an inherent flaw in Google's own systems. The disputed nature of this CVE highlights the complexity of vulnerability assessment in web applications where multiple layers of code and integration points can create ambiguous security boundaries.
The operational impact of this vulnerability, if it were to exist in legitimate Google Custom Search Engine implementations, would be significant for organizations relying on custom search functionality. Users could be exposed to various attack vectors including credential theft through session cookie manipulation, defacement of search results, or redirection to malicious content. The vulnerability could particularly affect enterprises or websites that have extended Google's search functionality with custom server-side code, creating potential attack surfaces that Google itself does not control. Organizations implementing custom search solutions would need to ensure proper input sanitization and output encoding practices to prevent such vulnerabilities from being exploited.
Mitigation strategies for this type of vulnerability would focus on implementing robust input validation and output encoding mechanisms. Web applications should employ proper parameter sanitization techniques, including HTML entity encoding of user inputs before rendering them in web pages. The implementation should follow security best practices such as those outlined in the OWASP Top Ten and the Web Application Security Consortium guidelines. Additionally, organizations should conduct regular security assessments of custom code implementations and ensure that any third-party modifications to Google's provided JavaScript components are properly validated. The principle of least privilege should be applied to web application components, and proper security headers including Content Security Policy should be implemented to prevent script execution from unauthorized sources. This vulnerability underscores the importance of comprehensive security testing throughout the software development lifecycle and the need for organizations to understand the security implications of integrating third-party components into their applications.