CVE-2004-1922 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 5.5 and 6.0 allocates memory based on the memory size written in the BMP file instead of the actual BMP file size, which allows remote attackers to cause a denial of service (memory consumption) via a small BMP file with has a large memory size.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/29/2021
Microsoft Internet Explorer versions 5.5 and 6.0 contain a critical memory allocation vulnerability that stems from improper validation of bitmap file dimensions during image processing. This flaw resides in the BMP file parsing mechanism where the browser incorrectly interprets the memory size field within the bitmap header structure rather than verifying the actual file size. The vulnerability manifests when a maliciously crafted BMP file contains a small actual file size but specifies an inflated memory allocation value in its header fields. This discrepancy allows attackers to craft payloads that appear benign in terms of file size but trigger excessive memory allocation requests within the browser's rendering engine.
The technical implementation of this vulnerability aligns with CWE-129, which addresses improper validation of array indices and buffer bounds, and specifically relates to improper input validation in image file processing. When Internet Explorer encounters such a malformed BMP file, it attempts to allocate memory based on the inflated size specified in the file header rather than the actual data contained within the file. This fundamental error in memory management creates a scenario where a few kilobytes of malicious data can trigger allocation of megabytes or even gigabytes of memory, depending on the values specified in the header fields. The flaw operates at the application layer and leverages the browser's image rendering capabilities to execute the denial of service attack.
The operational impact of this vulnerability extends beyond simple resource exhaustion as it can be exploited in various attack scenarios. Remote attackers can leverage this weakness to consume system resources on vulnerable systems, potentially leading to system instability, application crashes, or complete system hangs. The attack vector is particularly dangerous because it requires no user interaction beyond viewing the malicious image, making it suitable for drive-by download scenarios or web-based attacks. This vulnerability can be exploited in both targeted attacks against specific users and broader campaigns where attackers distribute malicious content through compromised websites or email attachments. The memory consumption aspect of this attack can be particularly problematic in resource-constrained environments or when multiple instances of the vulnerability are exploited simultaneously.
Security mitigations for this vulnerability should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves applying the security patches released by Microsoft that correct the memory allocation logic in the BMP file parser. Organizations should also implement network-level protections such as content filtering and image sanitization at perimeter defenses to prevent malicious BMP files from reaching end-user systems. Additionally, browser hardening techniques including disabling automatic image rendering for untrusted content and implementing memory limits for image processing components can provide defense-in-depth. From an ATT&CK framework perspective, this vulnerability maps to the T1059.007 technique related to application layer attacks and the T1499.004 technique for resource consumption attacks, emphasizing the need for comprehensive network security controls that address both the specific vulnerability and broader attack patterns.