Advisory ID: ngCERT-2025-050005
SUMMARY
ngCERT is aware of Cisco’s declaration of product End-of-Life (EoL) and End-of-Support (EoS) for Cisco Catalyst 1900, 2900, and 3900 series routers. This implies that Cisco no longer sells or supports the affected devices; hence, software/firmware updates, security patches, and bug fixes will cease. Additionally, technical support and warranty services are discontinued, while hardware replacement/services may become unavailable. The continued use of these devices is liable to introduce significant operational and security risks as well as compliance violations to enterprise and government networks. This advisory, therefore, highlights the security risks and consequences associated with the continued use of Cisco Catalyst 1900, 2900, and 3900 Series Routers and provides mitigation strategies for organizations and individuals.
Probability: High
Damage: Critical
Platform(s): Cisco Routers
DESCRIPTION
The Cisco Catalyst 1900, 2900, and 3900 routers, widely deployed in enterprise environments, have long since passed their official EoL milestones, implying that Cisco has discontinued all software updates, security patches, and hardware support for these devices as follows.
- Catalyst 1900 Series: End-of-Support Date - 31-May-2025
- Catalyst 2900 Series: End-of-Support Date - 31-Dec-2022
- Catalyst 3900 Series: End-of-Support Date- 31-Dec-2022.
Organizations with Cisco Catalyst 1900, 2900, and 3900 series routers deployed past their EoL and EoS dates are vulnerable to known exploits such as CVE-1999-1129, CVE-2015-0586, and CVE-2017-6742, making them prime targets for malware, ransomware, and unauthorized access. Troubleshooting becomes difficult without vendor support, scarcity of spare parts, and compatibility with modern protocols are limited. Additionally, as these routers age, the risk of sudden failure increases, potentially disrupting critical operations. The risks of maintaining these legacy systems far outweigh any perceived cost savings, making timely upgrades essential. Furthermore, outdated encryption and weak authentication further expose networks to threats.
CONSEQUENCES
Successful exploitation could lead to:
- Unpatched Exploits: These routers do not receive security updates, making them vulnerable to known and zero-day exploits.
- Regulatory & Compliance Violations: Non-compliance with standards like PCI DSS, HIPAA, or NIST due to insecure infrastructure. This could lead to fines, audits, or loss of certifications in regulated industries.
- Operational Instability: Hardware failure risks increase due to ageing components.
- Network Performance Degradation: Poor integration with newer systems or cloud services.
- Increased Attack Surface: Devices may be targeted by automated botnets or lateral movement in APT campaigns.
SOLUTION/MITIGATION
ngCERT recommends the following:
- Patch Immediate Device Assessment: Inventory all existing Cisco Catalyst 1900/2900/3900 routers and identify devices exposed to external networks or critical infrastructure segments.
- Replace and Upgrade to Supported Hardware: Plan and execute migration to currently supported Cisco platforms (e.g., Catalyst 9000 Series, ISR 4000 Series). Choose models that support modern standards or consider alternatives from other vendors.
- Network Segmentation & Isolation: If decommissioning is delayed, isolate these devices in a separate VLAN with strict access controls and monitor traffic for anomalies using intrusion detection systems (IDS).
- Disable unused services and interfaces: Turn off Telnet, HTTP, SNMPv1/2, and other outdated protocols in favor of SSH, HTTPS, and SNMPv3.
- Update Network Policies: Modify procurement and lifecycle management policies to decommission unsupported devices proactively.
- Align network hardware lifecycle with cybersecurity and compliance frameworks (e.g., NIST, ISO 27001).
REFERENCES