CVE-2002-1185 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 through 6.0 does not properly check certain parameters of a PNG file when opening it, which allows remote attackers to cause a denial of service (crash) by triggering a heap-based buffer overflow using invalid length codes during decompression, aka "Malformed PNG Image File Failure."
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability identified as CVE-2002-1185 represents a critical heap-based buffer overflow flaw in Microsoft Internet Explorer versions 5.01 through 6.0 that specifically manifests when processing malformed PNG image files. This vulnerability operates at the intersection of image parsing and memory management, creating a dangerous condition where legitimate image processing becomes a vector for system instability. The flaw resides in the decompression algorithm's handling of invalid length codes within PNG file structures, demonstrating how seemingly benign file format parsing can become a weapon for attackers seeking to disrupt system operations.
The technical execution of this vulnerability involves the exploitation of improper parameter validation within Internet Explorer's PNG handling subsystem. When the browser encounters a PNG file containing malformed length codes during decompression operations, the parsing routine fails to properly bounds-check memory allocations, leading to a heap-based buffer overflow condition. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent heap memory locations. The overflow occurs during the decompression phase of PNG processing, where the software attempts to allocate memory based on invalid length parameters provided in the image file structure.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more sophisticated attack vectors. While the immediate effect manifests as a browser crash, the underlying heap corruption can provide attackers with opportunities to execute arbitrary code or escalate privileges. The vulnerability affects a broad range of Windows users who rely on Internet Explorer for web browsing, particularly in enterprise environments where legacy browser support remains necessary. The attack vector is particularly concerning as it requires no special privileges or user interaction beyond visiting a malicious website or opening a specially crafted email attachment containing the vulnerable PNG file.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for system compromise. The attack surface is optimized for remote exploitation since it leverages the web browser's automatic image rendering capabilities, making it particularly dangerous in phishing campaigns or malicious websites. Security practitioners should recognize that this vulnerability demonstrates the importance of robust input validation and memory safety practices in multimedia processing components. The vulnerability also highlights the need for comprehensive security testing of image and media handling libraries, as these components often receive less scrutiny than core operating system functions. Organizations must implement layered defenses including browser hardening, content filtering, and regular security updates to protect against exploitation attempts targeting this specific heap overflow condition.