CVE-2015-0687 in IOS
Summary
by MITRE
The SNMP implementation in Cisco IOS 15.1(2)SG4 on Catalyst 4500 devices, when single-switch Virtual Switching System (VSS) is configured, allows remote authenticated users to cause a denial of service (device crash) by performing SNMP polling, aka Bug ID CSCuq04574.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/24/2017
The vulnerability described in CVE-2015-0687 represents a critical denial of service flaw within Cisco IOS software version 15.1(2)SG4 running on Catalyst 4500 series switches configured with Single-Switch Virtual Switching System. This issue specifically affects network infrastructure devices that utilize SNMP (Simple Network Management Protocol) for monitoring and management purposes, creating a significant operational risk for enterprise networks relying on these devices for core switching functions. The vulnerability manifests when authenticated remote users perform SNMP polling operations against the affected devices, leading to complete device crashes and subsequent service disruption.
The technical root cause of this vulnerability lies within the SNMP implementation of Cisco IOS, where improper handling of specific SNMP polling requests triggers a memory corruption condition that ultimately results in system instability and device crash. When SNMP queries are processed by the affected switch in VSS configuration, the system fails to properly validate or process certain SNMP packet structures, leading to a buffer overflow or similar memory management error that causes the device to reboot automatically. This flaw operates at the network protocol level and specifically targets the SNMP subsystem within the IOS operating system, making it particularly dangerous as it can be exploited by attackers who have gained legitimate network credentials.
The operational impact of this vulnerability extends beyond simple service disruption to encompass potential network outages and business continuity issues for organizations relying on Catalyst 4500 switches. When a device crashes and reboots, it creates immediate network disruption as the switch becomes unavailable for forwarding traffic, potentially causing cascading failures in network topology. Network administrators face the challenge of identifying and mitigating this vulnerability without compromising legitimate network management activities, as the attack vector requires only authenticated access to perform SNMP polling. This makes the vulnerability particularly concerning for environments where SNMP credentials might be compromised or where unauthorized personnel have access to network management systems.
Mitigation strategies for CVE-2015-0687 should focus on both immediate remediation and long-term network security improvements. Cisco recommends applying the appropriate software patches and updates to upgrade affected devices to versions that address the SNMP processing flaw. Network administrators should also implement SNMP access controls and monitoring to detect unusual polling patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in memory management, and can be categorized under ATT&CK technique T1499.001 for network denial of service attacks. Organizations should also consider implementing network segmentation and access control measures to limit SNMP access to only trusted management systems and personnel, reducing the attack surface for this specific vulnerability.