CVE-2006-4146 in GDB
Summary
by MITRE
Buffer overflow in the (1) DWARF (dwarfread.c) and (2) DWARF2 (dwarf2read.c) debugging code in GNU Debugger (GDB) 6.5 allows user-assisted attackers, or restricted users, to execute arbitrary code via a crafted file with a location block (DW_FORM_block) that contains a large number of operations.
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Analysis
by VulDB Data Team • 06/18/2025
The vulnerability identified as CVE-2006-4146 represents a critical buffer overflow flaw within the GNU Debugger (GDB) version 6.5 that affects the debugging information parsing mechanisms. This issue specifically targets the DWARF and DWARF2 debugging format handlers located in the dwarfread.c and dwarf2read.c source files respectively. The vulnerability arises when GDB processes debugging information contained within executable files or debug symbol files that utilize the DWARF debugging format standard commonly employed in Unix-like systems for storing debugging information. The flaw manifests when the debugger encounters a crafted file containing a location block with the DW_FORM_block encoding that contains an excessive number of operations, causing memory corruption during parsing operations.
The technical exploitation of this vulnerability occurs through the improper handling of debugging data structures within GDB's parsing routines. When the debugger attempts to process a malformed location block containing an excessive number of operations, the buffer allocated for storing these operations becomes insufficient to accommodate the actual data. This buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially leading to arbitrary code execution. The vulnerability is particularly concerning because it can be triggered by user-assisted attacks where a malicious user provides a specially crafted file that contains the malformed debugging information. Additionally, restricted users may exploit this vulnerability since the overflow can occur during normal debugging operations when processing legitimate files that contain corrupted debugging data.
The operational impact of CVE-2006-4146 extends beyond simple privilege escalation as it represents a remote code execution vulnerability that can be exploited in various contexts. The vulnerability affects systems running GDB 6.5 and potentially earlier versions, making it a significant concern for developers and system administrators who rely on GDB for debugging purposes. The attack vector requires minimal privileges since the vulnerability can be triggered through normal debugging operations, making it particularly dangerous in environments where debugging tools are frequently used. From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how debugging tools can become attack vectors when not properly secured against malformed input data. The vulnerability also maps to ATT&CK technique T1059.001 for command and scripting interpreter, as successful exploitation could allow attackers to execute arbitrary commands through the debugger's execution environment.
Mitigation strategies for this vulnerability involve immediate patching of affected GDB installations to version 6.5.1 or later, which contains the necessary fixes for the buffer overflow conditions. System administrators should also implement proper file validation procedures when processing debugging information, particularly when handling files from untrusted sources. The use of sandboxing techniques or restricted execution environments for debugging operations can help limit the potential impact of successful exploitation attempts. Additionally, monitoring for unusual debugging activity or unexpected crashes in GDB processes can help detect potential exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems running vulnerable versions of GDB, particularly those used in development environments where debugging files may be processed from external sources. Regular security audits of debugging tools and their usage patterns can help identify potential attack vectors and ensure proper security configurations are maintained throughout the system lifecycle.