CVE-2003-0886 in Hylafax
Summary
by MITRE
Format string vulnerability in hfaxd for Hylafax 4.1.7 and earlier allows remote attackers to execute arbitrary code.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2003-0886 represents a critical format string vulnerability within the hfaxd component of Hylafax versions 4.1.7 and earlier. This flaw exists in the fax server daemon that handles incoming and outgoing fax communications, making it a significant security concern for organizations relying on fax infrastructure for business operations. The vulnerability stems from improper input validation and handling of user-supplied data within the fax daemon's processing routines, specifically when formatting and displaying fax-related information. The affected system operates as a network service listening on specific ports for fax communication protocols, creating an attack surface that remote adversaries can exploit without requiring authentication.
The technical nature of this vulnerability falls under CWE-134, which specifically addresses format string vulnerabilities where attacker-controlled data is used as a format string parameter. In the context of hfaxd, when the fax daemon processes incoming fax data or user commands, it fails to properly sanitize input before passing it to functions like printf or sprintf. This allows attackers to inject format specifiers that can lead to memory corruption, information disclosure, or arbitrary code execution. The vulnerability occurs because the daemon does not validate that user-supplied data contains only legitimate format string characters, enabling attackers to manipulate memory layout and potentially overwrite critical program structures. The attack vector leverages the network-facing nature of the fax service, allowing remote exploitation from any location with network access to the affected system.
The operational impact of this vulnerability extends beyond simple code execution, as it can result in complete system compromise and unauthorized access to fax communication infrastructure. An attacker exploiting this vulnerability could gain root privileges on the affected system, allowing them to manipulate fax queues, access confidential fax documents, or use the compromised system as a launching point for further attacks within the network. The vulnerability affects organizations that rely on fax services for critical communications, potentially exposing sensitive information through memory disclosure attacks or enabling persistent backdoor access through code execution. Additionally, the attack can be automated and does not require specialized knowledge to execute, making it particularly dangerous in environments where fax services are not properly secured or monitored.
Mitigation strategies for CVE-2003-0886 should prioritize immediate patching of affected Hylafax installations to version 4.1.8 or later, which contains the necessary fixes for the format string vulnerability. Organizations should implement network segmentation to restrict access to fax services, limiting exposure through firewalls and access control lists that only permit trusted sources to communicate with the fax daemon. Additional protective measures include disabling unnecessary fax services, implementing proper input validation at multiple layers of the application stack, and monitoring for unusual fax activity patterns that might indicate exploitation attempts. System hardening practices such as running the fax daemon with minimal privileges, implementing intrusion detection systems, and conducting regular security assessments of fax infrastructure help reduce the overall risk. The vulnerability also highlights the importance of following secure coding practices and conducting thorough code reviews to prevent similar issues in other network services, aligning with ATT&CK technique T1059.007 for command and scripting interpreter usage and T1566 for credential access through exploitation of network services.