CVE-2003-1028 in Internet Explorer
Summary
by MITRE
The download function of Internet Explorer 6 SP1 allows remote attackers to obtain the cache directory name via an HTTP response with an invalid ContentType and a .htm file, which could allow remote attackers to bypass security mechanisms that rely on random names, as demonstrated by threadid10008.
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Analysis
by VulDB Data Team • 05/07/2019
The vulnerability described in CVE-2003-1028 represents a significant security flaw in Internet Explorer 6 Service Pack 1 that exploits a weakness in the browser's handling of HTTP responses and cache directory management. This issue specifically targets the download function of the browser, creating a scenario where remote attackers can manipulate the cache directory naming process through carefully crafted HTTP responses. The vulnerability operates by sending an HTTP response that contains an invalid Content-Type header combined with a .htm file extension, which triggers an unexpected behavior in the browser's caching mechanism.
The technical exploitation of this vulnerability stems from Internet Explorer's improper handling of cache directory names when processing malformed HTTP responses. When the browser encounters an HTTP response with an invalid Content-Type header but a .htm file extension, it fails to properly validate or sanitize the cache directory naming process. This improper validation allows attackers to predict or determine the cache directory structure that the browser uses to store downloaded content. The vulnerability is particularly concerning because it can be leveraged to bypass security mechanisms that depend on random or unpredictable cache directory names, which are commonly used as a defense-in-depth measure against certain types of attacks.
This vulnerability has substantial operational impact on systems running Internet Explorer 6 SP1, as it provides attackers with a method to circumvent cache-based security controls that rely on the assumption that cache directory names are sufficiently random and unpredictable. The attack vector is particularly dangerous because it can be executed remotely without requiring any special privileges or user interaction beyond visiting a malicious website. The demonstration using threadid10008 shows that this vulnerability was actively exploited in the wild, indicating that it posed a real threat to users and organizations relying on the affected browser version. The vulnerability affects the core security model of the browser's cache management system, potentially allowing attackers to access cached content that should remain protected.
The security implications extend beyond simple cache directory exposure, as this vulnerability can be combined with other attack vectors to create more sophisticated exploitation scenarios. Attackers could potentially use this technique to access cached sensitive information, manipulate cached files, or even facilitate further attacks by understanding the cache directory structure. From a compliance perspective, this vulnerability violates several security principles including the principle of least privilege and proper input validation, as outlined in various security frameworks and standards. The issue is categorized under CWE-20, which deals with improper input validation, and aligns with ATT&CK techniques related to privilege escalation and credential access through exploitation of software vulnerabilities. Organizations should consider implementing network-based mitigations such as web application firewalls and content filtering systems to prevent exploitation of this vulnerability while planning for browser upgrades to versions that properly address this cache directory naming issue.
The vulnerability demonstrates the importance of proper input validation in security-critical applications and highlights how seemingly minor implementation flaws in browser cache management can have significant security implications. It underscores the necessity of thorough security testing, particularly for components that handle user-supplied data and maintain persistent storage mechanisms. The issue also emphasizes the need for robust security architectures that do not rely solely on the unpredictability of cache directory names as a security control, since this approach can be defeated through careful exploitation of implementation weaknesses. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date software and the potential risks associated with running legacy browser versions that may contain unpatched security flaws.