CVE-2003-1559 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.22, and other 5 through 6 SP1 versions, sends Referer headers containing https:// URLs in requests for http:// URLs, which allows remote attackers to obtain potentially sensitive information by reading Referer log data.
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Analysis
by VulDB Data Team • 04/07/2017
This vulnerability exists in Microsoft Internet Explorer versions 5.22 and 5 through 6 Service Pack 1 where the browser incorrectly handles referer header information during mixed protocol requests. The technical flaw occurs when a user navigates from an https:// secure webpage to an http:// insecure webpage, causing the browser to include the full https:// URL in the referer header field of the subsequent http:// request. This behavior violates the expected security boundaries between secure and insecure content transmission. The vulnerability is classified as a cross-protocol information leakage issue that can be exploited through the manipulation of referer header data in web server logs and network traffic analysis. This flaw enables attackers to extract sensitive information that might otherwise remain protected by the secure protocol boundaries. The issue represents a violation of the principle of least privilege and information hiding that should be maintained between secure and insecure web communications.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially compromise user privacy and security. When web servers log referer headers, they inadvertently capture sensitive information from https:// URLs that could include session tokens, personal identifiers, or other confidential data. Attackers can exploit this by crafting malicious web pages that redirect users from secure https:// sites to insecure http:// sites, thereby harvesting sensitive information from the referer header logs of the target server. This vulnerability affects the fundamental security model of web browsers and can be leveraged to perform reconnaissance activities and gather intelligence about user behavior across secure and insecure domains. The attack vector is particularly concerning because it operates at the protocol level and can be executed without requiring any special privileges or advanced technical skills from the attacker.
Security professionals should recognize this vulnerability as a variant of information leakage through header manipulation and can map it to CWE-200 (Information Exposure) and CWE-310 (Cryptographic Issues). The vulnerability also aligns with ATT&CK technique T1071.004 (Application Layer Protocol: DNS) and T1566 (Phishing) when used in conjunction with social engineering attacks. Organizations should implement mitigations including disabling referer header transmission for sensitive applications, configuring web server logging to strip sensitive information from referer headers, and ensuring proper protocol handling through browser updates and security patches. Network administrators should monitor for unusual referer header patterns in their logs and implement proper access controls to limit information exposure. The vulnerability demonstrates the importance of maintaining strict protocol boundaries and proper header sanitization in web applications to prevent unintended information disclosure. Additionally, this issue highlights the need for comprehensive security testing that includes protocol interaction scenarios and cross-domain communication analysis to identify similar vulnerabilities in other software components.