CVE-2014-3377 in IOS XR
Summary
by MITRE
snmpd in Cisco IOS XR 5.1 and earlier allows remote authenticated users to cause a denial of service (process reload) via a malformed SNMPv2 packet, aka Bug ID CSCun67791.
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Analysis
by VulDB Data Team • 06/06/2017
The vulnerability identified as CVE-2014-3377 affects Cisco IOS XR software versions 5.1 and earlier, specifically targeting the snmpd daemon component. This issue represents a critical denial of service vulnerability that can be exploited by remote authenticated attackers to force system process reloads. The vulnerability stems from insufficient input validation within the SNMPv2 packet processing mechanism, creating a condition where malformed packets can trigger unexpected system behavior. The affected snmpd service in Cisco IOS XR systems processes SNMPv2 requests without proper sanitization of packet contents, allowing maliciously crafted data to disrupt normal operations. This vulnerability specifically impacts network infrastructure devices running Cisco IOS XR software, which are commonly deployed in enterprise and service provider networks for routing and switching operations.
The technical flaw manifests when the snmpd daemon receives a malformed SNMPv2 packet that contains improperly structured data or invalid field values. The vulnerability occurs during the parsing and processing of SNMPv2 protocol elements, where the system fails to validate packet boundaries, data types, or length specifications before attempting to handle the incoming data. This inadequate validation creates a path for attackers to craft specific packet sequences that cause the snmpd process to crash or restart unexpectedly. The malformed packet structure typically involves manipulation of SNMPv2 header fields, variable binding components, or community string handling that leads to memory corruption or exception handling failures within the daemon process. According to CWE classification, this vulnerability maps to CWE-121: Stack-based Buffer Overflow, as the improper input handling can lead to buffer overflows during packet processing operations. The vulnerability's impact is amplified by the fact that SNMP is a widely used network management protocol, making the attack surface relatively broad across network infrastructure deployments.
The operational impact of CVE-2014-3377 extends beyond simple service disruption, as it can compromise network availability and reliability in production environments. When exploited, the vulnerability forces process reloads that can temporarily interrupt network management capabilities, potentially leading to monitoring gaps and operational challenges for network administrators. The remote authenticated nature of the attack means that an attacker with valid SNMP credentials can leverage this vulnerability without requiring physical access or additional privileges. In enterprise network environments, this can result in cascading effects where network management systems lose connectivity to affected devices, potentially triggering false alarms and complicating incident response procedures. The vulnerability also aligns with ATT&CK technique T1499.001: Endpoint Denial of Service, as it specifically targets service availability through process disruption. Network outages caused by this vulnerability can be particularly problematic in service provider environments where continuous uptime is critical for maintaining customer service levels and operational reliability.
Mitigation strategies for CVE-2014-3377 should prioritize immediate software updates to Cisco IOS XR versions that address the SNMP packet validation issues. Network administrators should implement access controls to limit SNMP access to trusted management systems and ensure that SNMP community strings are properly configured with minimal required privileges. The implementation of SNMPv3 with strong authentication and encryption mechanisms provides additional protection against exploitation attempts. Network segmentation and firewall rules can be deployed to restrict SNMP traffic to necessary management stations only, reducing the attack surface for this vulnerability. Regular monitoring of SNMP traffic patterns and system logs can help detect potential exploitation attempts before they result in service disruption. Cisco recommends applying the relevant security patches and updates as soon as they become available, as the vulnerability affects the core network management functionality of IOS XR systems. Organizations should also consider implementing network intrusion detection systems that can identify malformed SNMP traffic patterns associated with this specific vulnerability. The mitigation approach should include comprehensive testing of updated firmware in non-production environments before deployment to ensure compatibility with existing network management systems and operational procedures.