CVE-2002-0527 in SOHO Firewall
Summary
by MITRE
Watchguard SOHO firewall before 5.0.35 allows remote attackers to cause a denial of service (crash and reboot) when SOHO forwards a packet with bad IP options.
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Analysis
by VulDB Data Team • 06/21/2024
The vulnerability identified as CVE-2002-0527 affects Watchguard SOHO firewall versions prior to 5.0.35, representing a critical denial of service weakness that can be exploited remotely by attackers to crash and reboot the affected device. This issue stems from the firewall's insufficient validation of IP packet options during forwarding operations, creating a scenario where malformed or maliciously crafted packets can trigger system instability. The vulnerability specifically manifests when the SOHO firewall processes packets containing invalid or malformed IP options, causing the device to crash and subsequently reboot, thereby disrupting network connectivity and availability for legitimate users.
The technical flaw resides in the packet processing logic of the Watchguard SOHO firewall implementation, where the system fails to properly validate IP options before forwarding packets through the network infrastructure. This represents a classic buffer over-read or improper input validation vulnerability that falls under the category of CWE-125, which describes out-of-bounds read conditions. The vulnerability occurs at the network layer processing stage where IP options are parsed and forwarded, without adequate sanitization of the options field. Attackers can craft packets with malformed IP options that, when processed by the vulnerable firewall, cause the system to enter an undefined state leading to a complete system crash and automatic reboot cycle.
From an operational impact perspective, this vulnerability presents a significant threat to network availability and business continuity, particularly in small office environments where Watchguard SOHO firewalls are commonly deployed. The remote exploitation capability means that attackers can initiate denial of service attacks from outside the network perimeter without requiring physical access or authentication credentials. The automatic reboot process creates a sustained disruption that can last several minutes, during which network services become unavailable and legitimate users lose connectivity. This type of vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a fundamental weakness in network infrastructure security that can be easily exploited to create service interruptions.
The exploitation of this vulnerability demonstrates the importance of proper input validation and defensive programming practices in network security devices. Organizations using affected Watchguard SOHO firewall versions should immediately implement mitigation strategies including firmware updates to version 5.0.35 or later, which contain the necessary patches to properly validate IP options before packet forwarding. Network administrators should also consider implementing intrusion detection systems that can monitor for suspicious packet patterns and deploy rate limiting or packet filtering rules to reduce the impact of potential attacks. The vulnerability serves as a reminder of the critical need for regular security updates and proper network device hardening practices, as outlined in NIST SP 800-41 guidelines for network security monitoring and incident response. Additionally, implementing network segmentation and access control measures can help limit the potential impact of such vulnerabilities by reducing the attack surface and containing the effects of successful exploitation attempts.