CVE-2008-3916 in GNU
Summary
by MITRE
Heap-based buffer overflow in the strip_escapes function in signal.c in GNU ed before 1.0 allows context-dependent or user-assisted attackers to execute arbitrary code via a long filename. NOTE: since ed itself does not typically run with special privileges, this issue only crosses privilege boundaries when ed is invoked as a third-party component.
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Analysis
by VulDB Data Team • 08/17/2019
The vulnerability identified as CVE-2008-3916 represents a critical heap-based buffer overflow in the GNU ed text editor, specifically within the strip_escapes function located in the signal.c file. This flaw exists in GNU ed versions prior to 1.0 and creates a significant security risk that can be exploited by context-dependent or user-assisted attackers to execute arbitrary code. The vulnerability manifests when processing a long filename that triggers the buffer overflow condition in the heap memory management system of the application.
The technical implementation of this vulnerability stems from inadequate input validation and memory boundary checking within the strip_escapes function. When GNU ed processes a filename that exceeds the allocated buffer size, the function fails to properly handle the overflow condition, allowing attackers to overwrite adjacent heap memory locations. This heap corruption can be carefully manipulated to redirect program execution flow and inject malicious code into the running process. The vulnerability operates at the application level and specifically targets the memory management routines that handle escape sequence processing within the signal handling code.
From an operational perspective, this vulnerability presents a substantial risk to systems where GNU ed is installed and potentially executed with elevated privileges. While the ed editor itself typically runs without special privileges, the vulnerability becomes particularly dangerous when ed is invoked as a third-party component or through privilege escalation scenarios. Attackers can exploit this weakness by crafting malicious filenames that trigger the buffer overflow during normal file processing operations, potentially leading to complete system compromise. The context-dependent nature of the attack means that successful exploitation requires specific conditions to be met, but the potential impact remains severe given the arbitrary code execution capability.
The security implications of this vulnerability align with CWE-121, which categorizes heap-based buffer overflows as a critical weakness in memory safety. This flaw also maps to ATT&CK technique T1059.007 for command and scripting interpreter, as the arbitrary code execution capability could enable attackers to execute malicious commands through the compromised ed process. Mitigation strategies should focus on upgrading to GNU ed version 1.0 or later, which includes proper buffer size validation and memory boundary checks. Additionally, system administrators should implement least privilege principles for ed usage, restrict file input from untrusted sources, and consider implementing input sanitization measures to prevent overly long filename inputs from reaching the vulnerable function. The vulnerability demonstrates the critical importance of proper memory management in text processing applications and highlights the need for comprehensive input validation in all system components that handle user-provided data.