CVE-2018-0161 in Enterprise Manager Ops Center
Summary
by MITRE
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software running on certain models of Cisco Catalyst Switches could allow an authenticated, remote attacker to cause a denial of service (DoS) condition, aka a GET MIB Object ID Denial of Service Vulnerability. The vulnerability is due to a condition that could occur when the affected software processes an SNMP read request that contains a request for the ciscoFlashMIB object ID (OID). An attacker could trigger this vulnerability by issuing an SNMP GET request for the ciscoFlashMIB OID on an affected device. A successful exploit could cause the affected device to restart due to a SYS-3-CPUHOG. This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS Software and are configured to use SNMP Version 2 (SNMPv2) or SNMP Version 3 (SNMPv3): Cisco Catalyst 2960-L Series Switches, Cisco Catalyst Digital Building Series Switches 8P, Cisco Catalyst Digital Building Series Switches 8U. Cisco Bug IDs: CSCvd89541.
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2018-0161 represents a critical denial of service weakness within the Simple Network Management Protocol implementation of Cisco IOS Software affecting specific Catalyst switch models. This flaw manifests when the affected network equipment processes SNMP read requests containing requests for the ciscoFlashMIB object identifier, creating a condition that can be exploited by authenticated remote attackers to disrupt network operations. The vulnerability specifically targets Cisco Catalyst 2960-L Series Switches, Cisco Catalyst Digital Building Series Switches 8P, and Cisco Catalyst Digital Building Series Switches 8U devices running vulnerable versions of IOS Software. The exploitation mechanism involves sending a specially crafted SNMP GET request targeting the ciscoFlashMIB OID, which triggers a system-level condition leading to device restarts.
The technical exploitation of this vulnerability stems from improper handling of SNMP GET requests within the SNMP subsystem of Cisco IOS. When an attacker sends an SNMP GET request for the ciscoFlashMIB OID, the system's processing logic fails to properly validate or handle the request, resulting in a CPU resource exhaustion condition known as SYS-3-CPUHOG. This error condition causes the switch to become unresponsive and eventually restarts automatically, effectively creating a denial of service scenario that can persist until manual intervention occurs. The vulnerability requires authentication to exploit, meaning that an attacker must have valid SNMP credentials to execute the attack, but this authentication requirement does not prevent the severity of the impact. The flaw demonstrates a classic buffer overflow or resource management issue within the SNMP processing code path that fails to properly handle specific OID requests.
The operational impact of CVE-2018-0161 extends beyond simple network disruption, potentially affecting business continuity and network availability for organizations relying on these switches for critical infrastructure operations. Network administrators may experience unexpected downtime during peak usage periods, and the automatic restart behavior can lead to cascading failures in network topology if multiple switches are affected simultaneously. The vulnerability affects both SNMPv2 and SNMPv3 implementations, meaning that organizations cannot avoid the issue by simply changing SNMP versions, and must address the underlying software flaw regardless of their authentication protocol choices. The fact that this vulnerability affects digital building series switches suggests it may be particularly concerning for enterprises with distributed network management systems where these switches serve as critical components in building automation and network monitoring.
Organizations affected by this vulnerability should prioritize immediate remediation through official Cisco software updates and patches addressing the specific flaw in the SNMP subsystem. The recommended mitigation strategy involves applying the latest IOS Software releases that contain fixes for the ciscoFlashMIB processing logic, while also implementing network segmentation and access control measures to limit SNMP access to trusted administrative networks. Network monitoring should be enhanced to detect unusual SNMP traffic patterns that might indicate exploitation attempts, and administrators should consider disabling SNMPv2 and SNMPv3 on switches where the vulnerability exists if these protocols are not essential for network management operations. The vulnerability aligns with CWE-122, which describes buffer overflow conditions, and represents a potential ATT&CK technique involving service stoppage and denial of service operations that can be classified under the system service manipulation category. Additionally, the vulnerability demonstrates the importance of proper input validation and resource management in network protocol implementations, as the flaw occurs specifically during the processing of a well-defined MIB object identifier rather than through more general protocol parsing failures.