CVE-2004-0159 in hsftp
Summary
by MITRE
Format string vulnerability in hsftp 1.11 allows remote authenticated users to cause a denial of service and possibly execute arbitrary code via file names containing format string characters that are not properly handled when executing an "ls" command.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2004-0159 represents a critical format string flaw within the hsftp 1.1 file transfer protocol implementation that exposes remote authenticated users to significant security risks. This issue stems from improper handling of user-supplied input during the execution of system commands, specifically when processing file names containing format string characters. The vulnerability operates at the intersection of input validation and command execution contexts, creating a pathway for malicious exploitation that can result in both denial of service conditions and potential arbitrary code execution within the target system's operational environment.
The technical root cause of this vulnerability lies in the improper sanitization of file names that are passed to system commands without adequate protection against format string specifiers such as %s, %d, or other formatting characters. When authenticated users upload or manipulate files with these special characters in their names, the hsftp application fails to properly escape or validate the input before incorporating it into system calls that execute the "ls" command. This flaw directly maps to CWE-134, which specifically addresses the use of untrusted data in format string contexts, making it a classic example of format string vulnerability exploitation. The implementation error occurs at the application layer where user input directly influences system command execution, bypassing normal input validation mechanisms that should prevent such malicious data processing.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential privilege escalation and system compromise. Remote authenticated users can leverage this weakness to craft specially formatted file names that, when processed by the vulnerable application, trigger format string exploitation techniques. These attacks can cause the application to crash or behave unpredictably, leading to service disruption, or in more sophisticated exploitation scenarios, allow attackers to execute arbitrary code with the privileges of the running process. The vulnerability particularly affects systems where hsftp operates with elevated permissions, as successful exploitation could potentially lead to full system compromise through the execution of malicious code within the application's security context.
Mitigation strategies for CVE-2004-0159 should prioritize immediate patching of the hsftp application to address the format string handling flaw, ensuring that all user-supplied input is properly sanitized before being incorporated into system commands. Organizations should implement input validation controls that filter or escape special characters in file names, particularly those that could be interpreted as format string specifiers. The implementation of proper command execution practices, such as using parameterized commands or avoiding direct string concatenation with user input, should be enforced throughout the application codebase. Additionally, system administrators should consider implementing network segmentation and access controls to limit the scope of potential exploitation, while monitoring for unusual file naming patterns that might indicate attempted exploitation attempts. This vulnerability demonstrates the critical importance of secure coding practices and proper input validation, aligning with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries exploit format string vulnerabilities to execute malicious commands. The remediation process should also include comprehensive security testing to identify similar vulnerabilities in other applications that may be susceptible to the same class of format string exploitation patterns.