Denial-of-Service Vulnerability (CVE‑2017‑12232) in Cisco ISR G2 Routers Allows Unauthenticated Reload
What It Is — A flaw in the implementation of a routing protocol on Cisco Integrated Services Routers Generation 2 (ISR G2) running Cisco IOS can be triggered by an unauthenticated, adjacent attacker, forcing the device to reload and causing a denial‑of‑service.
Exploitability — No public exploit code has been released, but the vulnerability is exploitable over the local network without credentials. CVSS v3.1 base score 7.5 (High).
Affected Products — Cisco IOS Software for Cisco Integrated Services Routers Generation 2 (ISR G2).
Why It Matters for Trust & Control Assurance
- Availability controls: A DoS event directly tests the organization’s ability to maintain service continuity, a core control objective across most frameworks.
- Continuous monitoring: Detecting unexpected router reloads requires logging and alerting that can be presented as audit evidence of an effective monitoring program.
- Patch management evidence: Demonstrating timely remediation of known IOS flaws provides defensible proof of due‑diligence to auditors and enterprise buyers.
Recommended Actions
- Verify the IOS version on all ISR G2 devices and apply Cisco’s security patch (or upgrade to a non‑vulnerable release).
- Enable and centralize syslog/telemetry for reload events; integrate alerts into a SIEM to detect abnormal restarts.
- Segment management traffic and enforce strict ACLs to limit adjacency exposure.
- Document the remediation steps and retain evidence in a compliance repository for audit readiness.
Source: CISA KEV – CVE‑2017‑12232