CVE-2001-0487 in AIX
Summary
by MITRE
AIX SNMP server snmpd allows remote attackers to cause a denial of service via a RST during the TCP connection.
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Analysis
by VulDB Data Team • 04/08/2019
The vulnerability identified as CVE-2001-0487 affects the AIX SNMP server daemon known as snmpd, which is a critical component for network management and monitoring in IBM AIX operating systems. This issue represents a classic denial of service vulnerability that exploits the TCP connection handling mechanisms within the SNMP service. The vulnerability specifically manifests when the snmpd daemon receives a RST (reset) packet during an active TCP connection, causing the service to crash or become unresponsive. This type of vulnerability falls under the category of network protocol implementation flaws that can be exploited by remote attackers without requiring authentication or specialized privileges.
The technical flaw resides in the snmpd daemon's insufficient error handling during TCP connection termination scenarios. When a remote attacker sends a TCP RST packet during an ongoing connection, the snmpd process fails to properly manage this unexpected termination signal, leading to a service disruption. This behavior demonstrates a lack of robust connection state management and proper socket error handling within the application layer. The vulnerability is particularly concerning because it can be triggered remotely over the network, making it accessible to any attacker who can reach the AIX system's SNMP port, typically UDP port 161 or TCP ports 161 and 162. The flaw essentially represents a buffer overflow or improper state management issue that causes the daemon to crash rather than gracefully handle the connection reset.
The operational impact of CVE-2001-0487 extends beyond simple service disruption, as it can compromise network monitoring capabilities and potentially affect system availability in mission-critical environments. Organizations relying on SNMP for network management, performance monitoring, and system administration may experience significant downtime when this vulnerability is exploited. The denial of service can occur without any indication of malicious activity, as the RST packet can be sent from any network location, making detection and attribution difficult. This vulnerability directly impacts the availability aspect of the CIA triad and can be classified under CWE-248, which deals with an exception being thrown but not caught, or CWE-119, which addresses weakness in memory management. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 - Endpoint Denial of Service, representing a network-based attack vector that targets system availability.
Mitigation strategies for CVE-2001-0487 should focus on both immediate protective measures and long-term architectural improvements. Organizations should implement network-level protections such as firewall rules that restrict access to SNMP ports from trusted networks only, and consider deploying intrusion detection systems that can identify and block suspicious RST packet patterns. The most effective immediate solution involves applying the appropriate IBM AIX security patches that address the snmpd daemon's connection handling issues. Network administrators should also consider implementing SNMPv3 with proper authentication and encryption mechanisms to reduce the attack surface. Additionally, monitoring systems should be configured to detect unusual patterns of connection resets and service disruptions. The vulnerability highlights the importance of proper input validation and error handling in network services, emphasizing the need for defensive programming practices that prevent service crashes from simple network anomalies. Organizations should also consider implementing redundant monitoring systems to ensure that network visibility remains available even if the primary SNMP service becomes unavailable.