CVE-2001-1034 in Hylafax Faxsurvey
Summary
by MITRE
Format string vulnerability in Hylafax on FreeBSD allows local users to execute arbitrary code via format specifiers in the -h hostname argument for (1) faxrm or (2) faxalter.
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Analysis
by VulDB Data Team • 04/29/2019
The vulnerability identified as CVE-2001-1034 represents a critical format string flaw within the Hylafax fax server software running on FreeBSD systems. This vulnerability specifically affects the faxrm and faxalter command-line utilities, which are part of the Hylafax fax handling suite designed for managing fax communications. The flaw occurs when these utilities process the -h hostname argument, creating an exploitable condition that can be leveraged by local attackers to execute arbitrary code with elevated privileges. Format string vulnerabilities arise when programs improperly handle user-supplied input as format strings, allowing attackers to manipulate memory locations and potentially gain complete system control.
The technical nature of this vulnerability stems from improper input validation within the Hylafax utilities, where the -h hostname argument is directly passed to printf or similar formatting functions without proper sanitization. This creates a classic format string vulnerability that falls under CWE-134, which specifically addresses the use of untrusted data in format string operations. When a local user provides maliciously crafted format specifiers in the hostname argument, the program's printf function interprets these specifiers as commands rather than literal text, enabling attackers to read from or write to arbitrary memory addresses. The vulnerability is particularly dangerous because it can be exploited by local users who may not have direct system access, as the utilities are typically installed with appropriate permissions that allow local execution.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be leveraged to completely compromise the system's integrity and confidentiality. Local attackers who exploit this vulnerability can execute arbitrary code with the privileges of the user running the faxrm or faxalter utilities, which typically operate with elevated permissions due to their role in fax system management. The attack vector is particularly concerning because it requires minimal privileges to initiate and can be executed from any local account on the system. This vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and demonstrates how local users can exploit system utilities to gain unauthorized access to system resources and potentially escalate privileges to root level access.
Mitigation strategies for CVE-2001-1034 should focus on immediate patching of the Hylafax software to address the format string vulnerability in the affected utilities. System administrators should ensure that all FreeBSD systems running Hylafax are updated with the latest security patches from the vendor or the FreeBSD security team. Additionally, implementing proper input validation and sanitization within the affected utilities would prevent malicious format specifiers from being processed, which aligns with the principle of least privilege and input validation practices recommended in security frameworks. Network segmentation and access controls should be implemented to limit local user access to critical system utilities, reducing the attack surface for potential exploitation. Regular security audits and vulnerability assessments should be conducted to identify similar format string vulnerabilities in other system utilities, as these types of flaws are common in legacy software implementations. Organizations should also consider implementing intrusion detection systems to monitor for suspicious usage patterns of the affected utilities, providing early warning capabilities for potential exploitation attempts.