Remote Memory Exhaustion in Cisco IOS XR DVMRP (CVE‑2020‑3569) Risks Service Disruption
What It Is – Cisco IOS XR’s implementation of the Distance Vector Multicast Routing Protocol (DVMRP) mishandles Internet Group Management Protocol (IGMP) packets. An unauthenticated remote attacker can trigger memory exhaustion, crashing the IGMP process and potentially bringing the router down.
Exploitability – The vulnerability is publicly disclosed (CVE‑2020‑3569) with a CVSS v3.1 base score of 7.5 (High). No public exploit code has been observed, but the attack requires only network‑level access to the affected interface.
Affected Products – Cisco IOS XR software (all versions prior to the vendor‑issued fix). The flaw is present in service‑provider and carrier‑grade routers that run IOS XR.
Why It Matters for Trust & Control Assurance
- Demonstrates the need for continuous monitoring of firmware and patch status on network infrastructure – a core control objective that maps to many frameworks (e.g., NIST CSF Identify and Protect).
- Provides audit‑ready evidence that you have remediated known CVEs and can prove a defensible security posture to regulators or enterprise customers.
- Highlights the importance of device hardening and change‑control processes to prevent unauthenticated remote impact on critical routing services.
Recommended Actions
- Apply Cisco’s security advisory patch for CVE‑2020‑3569 immediately.
- Verify IGMP process stability post‑patch and update monitoring rules to alert on abnormal memory usage.
- Incorporate this CVE into your continuous control‑evidence collection pipeline to demonstrate timely remediation.
Source: CISA KEV – CVE‑2020‑3569