CVE-2012-2141 in Net-SNMP
Summary
by MITRE
Array index error in the handle_nsExtendOutput2Table function in agent/mibgroup/agent/extend.c in Net-SNMP 5.7.1 allows remote authenticated users to cause a denial of service (out-of-bounds read and snmpd crash) via an SNMP GET request for an entry not in the extension table.
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Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2012-2141 represents a critical array index error within the Net-SNMP agent implementation that affects version 5.7.1. This flaw exists in the handle_nsExtendOutput2Table function located in the agent/mibgroup/agent/extend.c file, which is responsible for handling extension table operations within the Simple Network Management Protocol framework. The vulnerability specifically manifests when processing SNMP GET requests that target entries not present in the extension table, creating a condition where the software fails to properly validate array bounds before accessing memory locations.
The technical nature of this vulnerability stems from improper input validation and boundary checking within the SNMP agent's extension handling mechanism. When an authenticated remote attacker submits an SNMP GET request for a non-existent entry in the extension table, the system attempts to access memory beyond the allocated array boundaries. This out-of-bounds read condition occurs because the handle_nsExtendOutput2Table function does not adequately verify whether the requested index falls within the valid range of the extension table array. The flaw is categorized under CWE-129 as an insufficient input validation, specifically manifesting as an out-of-bounds read that can lead to arbitrary code execution or system instability.
From an operational perspective, this vulnerability creates a significant denial of service risk for systems running Net-SNMP 5.7.1. The remote authenticated attacker can exploit this weakness to crash the snmpd daemon process, effectively rendering the network management functionality unavailable. The impact extends beyond simple service interruption as the crash can potentially cause system instability, requiring manual intervention to restart the SNMP agent service. This vulnerability is particularly concerning in enterprise environments where SNMP monitoring is critical for network operations, as it can be leveraged to disrupt network management capabilities and potentially mask other malicious activities.
The attack vector requires that the attacker possess valid SNMP credentials to authenticate to the target system, making this a privilege escalation vulnerability in the context of authenticated access. However, the low barrier to exploitation means that any authenticated user with access to the SNMP agent can potentially trigger the denial of service condition. The vulnerability aligns with ATT&CK technique T1499.001 for network denial of service, specifically targeting network infrastructure through manipulation of management protocols. Organizations should note that this vulnerability exists in the agent component of Net-SNMP, making it distinct from other SNMP-related vulnerabilities that might affect the manager or trap handling components.
Mitigation strategies for CVE-2012-2141 should focus on immediate patching of the Net-SNMP agent to version 5.7.2 or later, which contains the necessary boundary checks to prevent out-of-bounds memory access. System administrators should also implement network segmentation and access controls to limit SNMP access to authorized personnel only, reducing the attack surface. Additional defensive measures include monitoring for unusual SNMP traffic patterns and implementing intrusion detection systems that can identify potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation in network management protocols and highlights the critical need for thorough code review processes in security-sensitive applications. Organizations should also consider implementing SNMPv3 with strong authentication mechanisms to reduce the risk of unauthorized access to SNMP agents.