CVE-2006-4438 in Dr.Web
Summary
by MITRE
Heap-based buffer overflow in SpIDer for Dr.Web Scanner for Linux 4.33, and possibly earlier versions, allows remote attackers to execute arbitrary code via an LHA archive with an extended header that contains a long directory name.
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Analysis
by VulDB Data Team • 01/30/2025
The vulnerability identified as CVE-2006-4438 represents a critical heap-based buffer overflow flaw in SpIDer, the scanning engine component of Dr.Web Scanner for Linux version 4.33 and potentially earlier releases. This vulnerability exists within the archive processing functionality of the security software, specifically when handling LHA (LHA is a compression format) archives that contain extended headers with excessively long directory names. The flaw stems from inadequate input validation and bounds checking during the parsing of archive metadata, creating a condition where attacker-controlled data can overwrite adjacent memory locations in the heap allocation space. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, which is a well-known class of memory safety issues that can lead to arbitrary code execution. This type of vulnerability is particularly dangerous because it can be exploited remotely through network-based attacks, making it a significant concern for systems running vulnerable versions of the Dr.Web scanner.
The technical exploitation of this vulnerability occurs when the SpIDer component processes an LHA archive that contains an extended header with an unusually long directory name field. During the parsing process, the software fails to properly validate the length of the directory name before copying it into a fixed-size buffer allocated on the heap. When the length exceeds the allocated buffer capacity, the excess data overflows into adjacent memory locations, potentially corrupting critical program data or control structures. This overflow can be carefully crafted to overwrite return addresses, function pointers, or other executable code locations, allowing an attacker to redirect program execution flow and inject malicious code. The vulnerability is particularly concerning because LHA archives are commonly used in various network protocols and file transfer systems, making them a likely attack vector for remote exploitation. The attack scenario typically involves an attacker sending a malicious LHA archive to a system running the vulnerable Dr.Web scanner, which then processes the archive and triggers the buffer overflow condition.
The operational impact of this vulnerability extends beyond simple code execution, as it can compromise the entire security infrastructure of systems running vulnerable versions of Dr.Web Scanner for Linux. Organizations relying on this security software for malware detection and prevention could find their systems completely compromised, allowing attackers to gain full control over affected machines. The vulnerability affects the core scanning functionality of the software, meaning that any system where the Dr.Web scanner is actively processing files or archives becomes a potential target for exploitation. This creates a significant risk for enterprise environments where automated scanning processes might encounter malicious archives from various sources including email attachments, file transfers, or web downloads. The vulnerability also impacts the integrity of the security software itself, as successful exploitation could allow attackers to bypass the very protection mechanisms that the software is designed to provide. From an ATT&CK perspective, this vulnerability maps to techniques involving code injection and privilege escalation, with potential for lateral movement within compromised networks.
Mitigation strategies for CVE-2006-4438 should focus on immediate patching of the vulnerable software components, as the primary fix involves updating to a version of Dr.Web Scanner for Linux that properly validates archive header lengths and implements robust bounds checking. System administrators should implement network-based restrictions to prevent the processing of LHA archives from untrusted sources, using firewalls and network access controls to limit exposure. Additionally, organizations should consider implementing sandboxing techniques for archive processing to isolate potentially malicious content from the main system. The vulnerability highlights the importance of input validation in security software, as proper bounds checking and length validation should be implemented for all external data processing. Security monitoring should be enhanced to detect unusual scanning behavior or potential exploitation attempts, particularly when dealing with archive files. Organizations should also consider alternative security solutions for environments where the vulnerable software cannot be immediately updated, ensuring that critical systems remain protected while remediation efforts are underway. Regular vulnerability assessments should be conducted to identify similar buffer overflow conditions in other security software components, as this class of vulnerability remains prevalent in legacy systems and can provide similar attack vectors for remote code execution.