CVE-2007-6537 in WinUAE
Summary
by MITRE
Stack-based buffer overflow in the zfile_gunzip function in zfile.c in WinUAE 1.4.4 and earlier allows user-assisted remote attackers to execute arbitrary code via a long filename in a gzipped archive, such as a (1) gz, (2) adz, (3) roz, or (4) hdz archive in a compressed floppy disk image.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2007-6537 represents a critical stack-based buffer overflow affecting WinUAE version 1.4.4 and earlier implementations. This flaw exists within the zfile_gunzip function located in the zfile.c source file, specifically targeting the decompression handling of compressed archive files. The vulnerability manifests when processing gzipped archive files containing excessively long filenames, creating a condition where memory allocated on the stack becomes overwritten beyond its intended boundaries. Attackers can exploit this weakness by crafting malicious compressed archive files with deliberately extended filenames, which when processed by the vulnerable WinUAE emulator, trigger the buffer overflow condition.
The technical exploitation of this vulnerability follows a well-established pattern of stack corruption that enables arbitrary code execution. When the zfile_gunzip function processes a compressed archive with an oversized filename, the function fails to properly validate the length of the filename before copying it into a fixed-size stack buffer. This validation failure allows attackers to overflow the buffer and overwrite adjacent memory locations including the return address on the stack. The attack vector is user-assisted remote exploitation, meaning that an attacker must convince a victim to open a maliciously crafted compressed archive file through the WinUAE emulator. The vulnerable archive formats include standard gzip (.gz), adz, roz, and hdz file extensions, all of which are commonly used in floppy disk image compression within the Amiga emulation environment.
The operational impact of this vulnerability extends beyond simple code execution, representing a significant threat to system security within the emulation environment. Successful exploitation allows attackers to gain full control over the system running WinUAE, potentially enabling privilege escalation, data exfiltration, or the installation of persistent backdoors. The vulnerability affects users who rely on WinUAE for Amiga system emulation, particularly those who may encounter compressed disk images from untrusted sources or who regularly handle floppy disk images from unknown origins. Given the nature of emulation software, the attack surface includes not only the immediate system but potentially any data processed through the vulnerable emulator, making this a particularly concerning flaw for users handling sensitive information or operating in security-sensitive environments.
Mitigation strategies for CVE-2007-6537 should focus on immediate patching of the vulnerable WinUAE version to a patched release that properly validates filename lengths before buffer operations. Organizations should implement strict file validation policies for compressed archives, particularly those used in emulation environments, and establish automated scanning systems to detect potentially malicious archive files. The vulnerability aligns with CWE-121, stack-based buffer overflow, and represents a classic example of improper input validation that enables arbitrary code execution. From an ATT&CK framework perspective, this vulnerability maps to techniques involving code injection and privilege escalation, with potential for lateral movement if exploited in multi-user environments. System administrators should also consider implementing network-based restrictions on compressed file handling and establishing secure decompression procedures that validate archive integrity before processing. The remediation process requires comprehensive testing to ensure that the patched version maintains compatibility with legitimate use cases while eliminating the buffer overflow condition.