CVE-2006-3845 in WinRar
Summary
by MITRE
Stack-based buffer overflow in lzh.fmt in WinRAR 3.00 through 3.60 beta 6 allows remote attackers to execute arbitrary code via a long filename in a LHA archive.
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Analysis
by VulDB Data Team • 06/23/2019
The vulnerability identified as CVE-2006-3845 represents a critical stack-based buffer overflow flaw within the lzh.fmt module of WinRAR versions ranging from 3.00 through 3.60 beta 6. This vulnerability stems from inadequate input validation mechanisms when processing filenames within LHA archive files, creating a condition where maliciously crafted archive contents can overwrite adjacent memory locations on the stack. The flaw specifically manifests when WinRAR attempts to extract or display filenames that exceed predetermined buffer limits, allowing attackers to manipulate the program execution flow through controlled memory corruption.
The technical implementation of this vulnerability aligns with CWE-121, which categorizes stack-based buffer overflow conditions as a fundamental memory safety issue. Attackers can exploit this weakness by crafting specially formatted LHA archives containing excessively long filenames that trigger the buffer overflow during archive processing. The overflow enables arbitrary code execution with the privileges of the user running WinRAR, potentially allowing full system compromise. This vulnerability operates under the ATT&CK framework's execution technique category, specifically targeting application execution through malicious file handling mechanisms.
The operational impact of CVE-2006-3845 extends beyond simple code execution, as it provides attackers with persistent access to target systems through archive-based attack vectors. Given that WinRAR was widely used for decompressing archived files across various platforms, the vulnerability created a significant attack surface that could be leveraged through email attachments, web downloads, or file sharing networks. The exploitation typically requires the victim to interact with a maliciously crafted LHA archive, making social engineering a common accompanying attack vector.
Mitigation strategies for this vulnerability include immediate patching of WinRAR installations to versions that properly validate filename lengths and implement proper buffer management techniques. System administrators should disable automatic extraction of untrusted archives and implement file type filtering mechanisms to prevent execution of potentially malicious archive files. Additionally, network-based intrusion detection systems can be configured to monitor for suspicious LHA archive patterns, while endpoint protection solutions should be updated to recognize and block malicious archive content. The vulnerability highlights the importance of proper input validation and memory safety practices in archive processing software, emphasizing the need for defensive programming techniques to prevent similar issues in future implementations.