CVE-2002-1050 in HylaFAX
Summary
by MITRE
Buffer overflow in HylaFAX faxgetty before 4.1.3 allows remote attackers to cause a denial of service, and possibly execute arbitrary code, via a long line of image data.
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Analysis
by VulDB Data Team • 06/29/2024
The vulnerability identified as CVE-2002-1050 represents a critical buffer overflow flaw in the HylaFAX faxgetty component version 4.1.2 and earlier. This issue arises within the fax processing subsystem that handles incoming fax communications through the serial port interface. The vulnerability specifically manifests when the faxgetty daemon receives image data from fax machines, where the system fails to properly validate the length of incoming data streams before processing them. This fundamental flaw in input validation creates an exploitable condition that can be leveraged by remote attackers to compromise the affected system. The buffer overflow occurs during the parsing of fax image data, where the application does not enforce proper bounds checking on the data length, allowing maliciously crafted data to overwrite adjacent memory regions.
The technical implementation of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite memory locations. The flaw exists in the faxgetty daemon's handling of image data streams, particularly when processing the line data that constitutes fax image information. Attackers can craft fax transmissions containing excessively long data lines that exceed the allocated buffer space, causing the application to overwrite adjacent memory segments including return addresses and control data. This memory corruption can lead to arbitrary code execution when the corrupted execution flow redirects program control to attacker-controlled code. The vulnerability is particularly dangerous because it can be exploited remotely through the fax transmission interface without requiring authentication, making it a significant threat to fax server security.
The operational impact of CVE-2002-1050 extends beyond simple denial of service to potentially enable complete system compromise. When exploited successfully, the buffer overflow can result in arbitrary code execution with the privileges of the faxgetty daemon process, typically running with elevated system permissions. This privilege escalation capability allows attackers to gain unauthorized access to the fax server, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The vulnerability affects organizations that rely on fax services for business operations, creating potential disruption to critical communication channels. The remote exploit capability means that attackers can target systems from outside the local network, making the vulnerability particularly concerning for organizations with internet-facing fax servers. Additionally, the denial of service aspect can be used to disrupt legitimate fax communications, causing operational disruptions that may impact business continuity.
Mitigation strategies for this vulnerability require immediate implementation of the vendor-provided patch, which updates the faxgetty component to version 4.1.3 or later. Organizations should also implement network segmentation to isolate fax servers from critical network segments, reducing the attack surface available to potential attackers. Access controls should be implemented to restrict fax server communication to authorized devices only, preventing unauthorized fax machines from connecting to the system. Network monitoring should be enhanced to detect unusual fax transmission patterns that might indicate exploitation attempts, particularly focusing on anomalous data lengths in fax communications. Security configurations should include disabling unnecessary fax services and implementing proper input validation at multiple layers of the system architecture. The ATT&CK framework categorizes this vulnerability under T1203, which covers Exploitation for Execution, highlighting the need for defensive measures including runtime protection, network segmentation, and access control hardening to prevent exploitation. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow conditions in other fax and communication services that may be susceptible to similar attacks.