CVE-2003-1420 in Web Browser
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Opera 6.0 through 7.0 with automatic redirection disabled allows remote attackers to inject arbitrary web script or HTML via the HTTP Location header.
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Analysis
by VulDB Data Team • 06/29/2021
This cross-site scripting vulnerability exists in Opera web browsers version 6.0 through 7.0 when automatic redirection is disabled. The flaw specifically targets the handling of the HTTP Location header during web navigation processes. When a web server sends a redirect response with a Location header containing malicious script code, Opera's browser engine fails to properly sanitize this input before rendering it in the browser context. This represents a classic client-side injection vulnerability that falls under CWE-79 - Improper Neutralization of Input During Web Page Generation. The vulnerability is particularly concerning because it operates at the HTTP protocol level where the Location header is commonly used for redirecting users between pages. Attackers can exploit this by crafting malicious URLs that, when accessed, trigger the vulnerable redirect behavior. The security implications extend beyond simple script injection as this vulnerability can be leveraged to execute arbitrary code within the context of the user's browser session. The attack vector is particularly effective because it requires no user interaction beyond visiting a malicious website, making it a passive threat that can be exploited through various means including phishing campaigns or compromised websites. This vulnerability directly maps to ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as it enables the execution of malicious javascript code through crafted HTTP headers. The impact is significant as successful exploitation can lead to session hijacking, credential theft, or redirection to malicious sites that appear legitimate to users.
The technical flaw stems from Opera's inadequate input validation and sanitization of the HTTP Location header when automatic redirection is disabled. The browser fails to properly escape or filter special characters that could be interpreted as HTML or script tags within the redirect URL. This occurs during the browser's processing of HTTP responses and demonstrates a lack of proper output encoding practices. When the browser encounters a Location header containing potentially malicious content, it does not perform the necessary sanitization to prevent script execution. The vulnerability is particularly dangerous because it bypasses typical user awareness mechanisms that might detect suspicious content, as the malicious script is embedded within an HTTP header rather than visible HTML content. This makes detection and prevention more challenging for both users and security systems. The flaw is exacerbated by the fact that disabling automatic redirection creates a scenario where the browser processes the Location header in a different code path that lacks proper security checks. The vulnerability affects the browser's core HTTP processing functionality and represents a failure in the browser's security model to properly handle untrusted input from network responses.
The operational impact of this vulnerability extends far beyond simple script injection attacks and poses serious threats to user security and privacy. An attacker can craft malicious redirects that steal session cookies, perform unauthorized actions on behalf of users, or redirect them to phishing sites that mimic legitimate services. The vulnerability can be exploited through various attack vectors including compromised websites, malicious advertisements, or email links that direct users to malicious content. Users may be unaware of the attack since the malicious script executes automatically without requiring user interaction beyond visiting the compromised site. This makes the vulnerability particularly dangerous in enterprise environments where users may visit numerous websites daily. The potential for credential theft is significant as attackers can use the XSS vulnerability to capture authentication tokens and session identifiers. The vulnerability also enables more sophisticated attacks such as browser fingerprinting, data exfiltration, or the installation of malicious browser extensions. Organizations may experience reputation damage if users are affected by attacks exploiting this vulnerability, and the security incident response costs can be substantial when dealing with cross-site scripting exploits. The vulnerability's impact is amplified because it affects a widely used browser version that many users may not have updated, creating a persistent security risk.
Mitigation strategies for this vulnerability should focus on both immediate browser updates and defensive measures. The most effective solution is to upgrade to a newer version of Opera where this vulnerability has been patched, as the flaw exists specifically in versions 6.0 through 7.0. Organizations should implement comprehensive browser security policies that mandate regular updates and patches for all web browsers in use. Network-level defenses can include implementing web application firewalls that monitor for suspicious HTTP headers and can block or sanitize Location headers containing potentially malicious content. Browser security configurations should be hardened to disable unnecessary features and implement stricter content filtering policies. Users should be educated about the risks of visiting untrusted websites and the importance of keeping their browsers updated. Additional security measures include implementing content security policies that limit script execution and using security extensions that provide additional protection against XSS attacks. The vulnerability highlights the importance of proper input validation at all levels of web application processing and demonstrates why automated security testing should include coverage of HTTP header processing. Organizations should also consider implementing monitoring solutions that can detect unusual redirect patterns or suspicious Location header content that may indicate exploitation attempts. Regular security assessments and penetration testing should include evaluation of browser-based vulnerabilities to ensure comprehensive protection against similar threats.