CVE-2002-0835 in Secure OS
Summary
by MITRE
Preboot eXecution Environment (PXE) server allows remote attackers to cause a denial of service (crash) via certain DHCP packets from Voice-Over-IP (VOIP) phones.
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Analysis
by VulDB Data Team • 07/18/2019
The vulnerability identified as CVE-2002-0835 represents a significant security flaw within Preboot Execution Environment PXE server implementations that enables remote attackers to execute denial of service attacks through carefully crafted DHCP packets originating from Voice-Over-IP devices. This vulnerability operates at the network infrastructure level, specifically targeting the PXE boot process that occurs before operating system initialization, making it particularly dangerous as it can disrupt critical system provisioning and recovery mechanisms. The flaw stems from inadequate input validation within the PXE server's DHCP packet processing logic, where malformed or unexpected packet structures from VOIP phones can trigger unexpected behavior leading to system crashes or complete service unavailability.
The technical nature of this vulnerability aligns with CWE-129, which addresses issues related to input validation and improper handling of malformed data in network protocols. The attack vector specifically exploits the interaction between PXE servers and DHCP clients, where VOIP phones, configured with specific network parameters or operating in certain network environments, can send DHCP packets containing malformed options or unexpected data sequences. These packets, when processed by vulnerable PXE servers, trigger buffer overflows, memory corruption, or state machine failures that result in the server crashing or becoming unresponsive. The vulnerability demonstrates how interconnected network services can create unexpected attack surfaces where seemingly benign devices can be weaponized to compromise infrastructure availability.
From an operational impact perspective, this vulnerability poses serious risks to enterprise network environments where PXE boot is commonly used for system provisioning, deployment, and recovery operations. Organizations relying on PXE-based infrastructure for automated OS deployment, system maintenance, or disaster recovery scenarios face potential disruptions that could cascade across their entire network infrastructure. The attack can be executed remotely without requiring authentication or elevated privileges, making it particularly dangerous as it can be exploited by attackers from outside the network perimeter. The disruption caused by such attacks can result in extended downtime for critical systems, potentially affecting business operations, system maintenance windows, and overall network availability for legitimate users.
Mitigation strategies for this vulnerability should encompass multiple layers of defense including network segmentation to isolate PXE servers from potentially compromised VOIP networks, implementing strict DHCP packet filtering rules to validate incoming packets before they reach the PXE server, and applying firmware updates from vendors that address the specific input validation flaws. Network administrators should also consider implementing monitoring solutions to detect unusual DHCP traffic patterns that may indicate exploitation attempts, while establishing incident response procedures specifically designed to handle PXE server disruptions. The remediation process requires careful testing of updates to ensure that patched versions maintain compatibility with existing PXE boot configurations and network infrastructure components, as improper implementation could introduce additional service disruptions. Organizations should also review their overall network security posture to identify and address similar vulnerabilities in other network services that may be susceptible to similar input validation attacks, following principles outlined in the mitre attack framework for network infrastructure targeting.