CVE-2004-0623 in GNATS
Summary
by MITRE
Format string vulnerability in misc.c in GNU GNATS 4.00 may allow remote attackers to execute arbitrary code via format string specifiers in a string that gets logged by syslog.
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Analysis
by VulDB Data Team • 06/30/2021
The vulnerability identified as CVE-2004-0623 represents a critical format string flaw within the GNU GNATS 4.00 system administration tool suite. This issue manifests in the misc.c source file where improper input validation occurs during log message processing, specifically when syslog is invoked with user-supplied data. The flaw enables malicious actors to craft specially formatted input that gets interpreted as format specifiers rather than literal text, creating a pathway for arbitrary code execution. This vulnerability type falls under the CWE-134 classification, which specifically addresses the use of format strings with user-controlled data without proper validation or sanitization.
The technical exploitation of this vulnerability occurs when GNATS processes user input that subsequently gets passed to syslog without appropriate formatting controls. When an attacker can influence the content of log messages, they can inject format specifiers such as %x, %s, or %n that cause the logging function to read from memory locations or write data to specific addresses. This behavior can be leveraged to overwrite critical program memory, redirect execution flow, or extract sensitive information from the system. The remote nature of this attack means that adversaries can exploit the vulnerability without requiring local access, making it particularly dangerous in networked environments where GNATS is deployed for bug tracking and system administration purposes.
The operational impact of CVE-2004-0623 extends beyond simple code execution, as it can lead to complete system compromise when attackers leverage the vulnerability to gain unauthorized access to administrative functions. Since GNATS is commonly used for managing software development workflows and bug tracking across multiple systems, exploitation could allow attackers to manipulate bug reports, access sensitive development information, or establish persistent access points within the organization's infrastructure. The vulnerability affects systems where GNATS is installed and actively logging user input, particularly those configured to log detailed error messages or user submissions. This issue aligns with ATT&CK technique T1059.007 for command and script injection, as the exploitation chain typically involves crafting malicious input that gets executed through the vulnerable logging mechanism.
Mitigation strategies for this vulnerability primarily focus on implementing proper input validation and sanitization practices within the GNATS codebase. Organizations should immediately apply patches released by the GNU project or upgrade to newer versions of GNATS that address this specific format string vulnerability. System administrators should also consider implementing input filtering at the network level to prevent malicious format specifiers from reaching the vulnerable application. Additional protective measures include configuring syslog to use fixed format strings rather than user-supplied data, implementing proper access controls to limit who can submit data to the GNATS system, and monitoring log files for suspicious format string patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of following secure coding practices and adhering to the principle of least privilege in system administration tools to prevent remote code execution through input manipulation.