CVE-2002-0024 in Internet Explorer
Summary
by MITRE
File Download box in Internet Explorer 5.01, 5.5 and 6.0 allows an attacker to use the Content-Disposition and Content-Type HTML header fields to modify how the name of the file is displayed, which could trick a user into believing that a file is safe to download.
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Analysis
by VulDB Data Team • 04/07/2017
This vulnerability resides in the file download handling mechanism of internet explorer versions 5.01, 5.5, and 6.0, representing a classic case of user interface deception through HTTP header manipulation. The flaw specifically exploits the interaction between the Content-Disposition and Content-Type HTTP headers that browsers use to determine how to handle file downloads. When these headers are manipulated by an attacker, they can alter the filename displayed in the download dialog box, creating a false impression about the nature of the file being downloaded. This represents a significant bypass of user security awareness mechanisms that rely on visual cues to make informed decisions about file downloads.
The technical implementation of this vulnerability stems from how internet explorer processes HTTP response headers during file transfer operations. When a web server sends a response with specific Content-Disposition headers that include a filename parameter, or when Content-Type headers are used to suggest file types, the browser's download dialog box uses these values to display the filename to users. An attacker can craft malicious HTTP responses that contain misleading filenames in the Content-Disposition header, causing the browser to display a benign-looking filename while actually downloading a malicious executable or script file. This manipulation occurs at the application layer where the browser interprets HTTP headers, making it particularly dangerous as it operates within the normal HTTP protocol behavior without triggering standard network-based security mechanisms.
The operational impact of this vulnerability extends beyond simple social engineering as it directly undermines user trust in the browser's download interface and creates a pathway for various malicious activities. Users who encounter a download dialog showing a seemingly harmless filename like "readme.txt" or "update.exe" may be deceived into executing files that are actually malicious payloads such as trojans, backdoors, or other harmful software. This vulnerability aligns with CWE-611, which addresses improper access control in web applications, and can be classified under ATT&CK technique T1193 as it leverages user interface manipulation to facilitate malicious code execution. The attack vector specifically targets the user's decision-making process during download operations, making it particularly effective in phishing campaigns and drive-by download scenarios where users are less likely to scrutinize file names when they appear to be legitimate system files.
Mitigation strategies for this vulnerability require both immediate browser updates and enhanced user awareness measures. The most effective solution involves updating to newer versions of internet explorer that properly validate and sanitize filename parameters from HTTP headers, though this particular vulnerability was addressed through service packs and security updates for the affected versions. Organizations should implement strict content filtering and validation at network boundaries to detect and block suspicious Content-Disposition headers. Additionally, users should be trained to always verify file extensions and content types regardless of what the download dialog displays, as the visual deception can be particularly effective against less security-conscious individuals. The vulnerability also highlights the importance of implementing defense-in-depth strategies that do not rely solely on user interface elements for security decisions, as demonstrated by the need for additional validation mechanisms beyond simple visual cues.