CVE-2003-0531 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 SP3 through 6.0 SP1 allows remote attackers to access and execute script in the My Computer domain using the browser cache via crafted Content-Type and Content-Disposition headers, aka the "Browser Cache Script Execution in My Computer Zone" vulnerability.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2003-0531 represents a critical security flaw in Microsoft Internet Explorer versions 5.01 SP3 through 6.0 SP1 that exploits the browser's handling of web content within the My Computer zone security context. This vulnerability specifically targets the browser's cache mechanism and demonstrates how improper content type handling can lead to privilege escalation and arbitrary code execution. The flaw occurs when Internet Explorer processes web content with maliciously crafted Content-Type and Content-Disposition HTTP headers, allowing attackers to bypass security restrictions that normally prevent script execution within the My Computer zone.
The technical implementation of this vulnerability stems from Internet Explorer's trust model and cache handling behavior when processing web resources. When a browser encounters a resource with specific combinations of Content-Type and Content-Disposition headers, it incorrectly interprets the content as originating from the My Computer zone rather than the originating web server. This misclassification occurs because the browser cache does not properly validate the security context of cached content against the actual source and content type. The vulnerability is particularly dangerous because it leverages the browser's cache to store malicious content that can be executed with elevated privileges within the My Computer security zone, which typically has higher permissions than the Internet zone.
From an operational perspective, this vulnerability creates a significant threat vector for attackers seeking to compromise systems running affected Internet Explorer versions. The attack requires the victim to visit a malicious website that serves content with the crafted headers, but once executed, the malicious script can access local system resources, read files, and potentially escalate privileges. The My Computer zone in Internet Explorer is designed to provide higher privileges for local content, making this vulnerability particularly dangerous as it allows attackers to execute malicious code with the same privileges as the local user. This vulnerability directly impacts the principle of least privilege and demonstrates how browser cache mechanisms can be exploited to undermine security boundaries. The vulnerability aligns with CWE-224, which addresses improper handling of security-sensitive resources, and represents a classic example of how browser security zones can be bypassed through content manipulation.
The attack vector for this vulnerability involves crafting HTTP responses with specific Content-Type and Content-Disposition headers that trick Internet Explorer into caching content in a manner that violates normal security boundaries. When users visit malicious websites, the browser stores the crafted content in its cache with incorrect security context information, allowing subsequent access to execute malicious scripts with My Computer zone privileges. This attack can be particularly effective in corporate environments where users may have elevated privileges and where browser cache persistence can maintain the malicious content across multiple browsing sessions. Security researchers have noted that this vulnerability is particularly challenging to detect because it relies on normal browser caching behavior rather than obvious malicious code injection, making it difficult to identify through standard network monitoring or security scanning tools. Organizations should consider implementing browser security policies that disable automatic caching of content from untrusted sources and ensure that all Internet Explorer installations are updated to versions that properly address this vulnerability through the Microsoft security update process. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation, highlighting its potential for both code execution and privilege elevation within targeted systems.