CVE-2002-1170 in net-snmp
Summary
by MITRE
The handle_var_requests function in snmp_agent.c for the SNMP daemon in the Net-SNMP (formerly ucd-snmp) package 5.0.1 through 5.0.5 allows remote attackers to cause a denial of service (crash) via a NULL dereference.
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Analysis
by VulDB Data Team • 06/09/2018
The vulnerability described in CVE-2002-1170 represents a critical denial of service flaw within the Net-SNMP daemon implementation. This issue affects versions 5.0.1 through 5.0.5 of the Net-SNMP package, which was formerly known as ucd-snmp and serves as a widely deployed SNMP (Simple Network Management Protocol) implementation across network infrastructure devices. The vulnerability specifically resides in the handle_var_requests function located within the snmp_agent.c source file, which forms a core component of the SNMP daemon's processing pipeline for handling variable requests from remote management stations.
The technical nature of this vulnerability stems from a NULL pointer dereference condition that occurs when the handle_var_requests function processes certain malformed SNMP requests. When a remote attacker crafts and sends a specially crafted SNMP packet containing malformed variable requests, the function fails to properly validate input parameters before attempting to dereference a pointer that remains NULL. This fundamental programming error creates an exploitable condition where the SNMP daemon process crashes and terminates unexpectedly, leading to a complete denial of service for the managed network device. The vulnerability aligns with CWE-476 which categorizes NULL pointer dereference issues as a common programming error that can lead to system instability and service interruption.
The operational impact of CVE-2002-1170 extends beyond simple service disruption as it can severely compromise network management capabilities and overall system availability. Network administrators rely on SNMP daemons for critical monitoring and management functions, making this vulnerability particularly dangerous in production environments where continuous network oversight is essential. When exploited, the vulnerability can cause network devices to become unresponsive to management requests, effectively isolating them from network management systems and potentially leading to extended outages. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter without requiring local access or authentication credentials, making it a significant threat vector for network attackers.
Mitigation strategies for this vulnerability primarily focus on immediate version updates and system hardening measures. The most effective approach involves upgrading to Net-SNMP versions 5.0.6 or later, where the NULL pointer dereference issue has been resolved through proper input validation and pointer checking mechanisms. System administrators should also implement network segmentation and access control measures to limit SNMP traffic to trusted management stations only, reducing the attack surface for potential exploitation. Network monitoring should be enhanced to detect unusual SNMP traffic patterns that might indicate exploitation attempts, while regular security audits should verify that all network devices running SNMP daemons are properly patched and configured according to security best practices. This vulnerability demonstrates the importance of thorough input validation in network services and aligns with ATT&CK technique T1499.004 which covers network denial of service attacks targeting network infrastructure components.