Cisco IOS HTTP Header Injection (CVE‑2023‑20198) Scans Detected Across Global Networks
What It Is — The Cisco IOS Software HTTP/HTTPS request‑header injection flaw (CVE‑2023‑20198) allows an unauthenticated remote attacker to inject arbitrary HTTP headers into traffic processed by affected IOS releases. Successful exploitation can enable cross‑site scripting, cache poisoning, or facilitate further network‑level attacks. The vulnerability carries a CVSS v3.1 base score of 7.5 (High) and has been publicly disclosed with patches available from Cisco. Recent scans reported by the SANS Internet Storm Center show active probing of legacy IOS devices for this flaw, indicating that threat actors are still hunting for unpatched equipment. No successful compromise has been confirmed in the report, but the volume of attempts suggests a heightened risk for networks that have not applied the remediation.
Affected Products — Cisco IOS (all releases vulnerable to CVE‑2023‑20198, primarily older 15.x and 16.x series).
Why It Matters for Trust & Control Assurance — The activity tests an organization’s control over secure configuration management and continuous monitoring of network device logs.
Recommended Actions
- Identify all Cisco IOS assets and verify firmware versions against Cisco’s advisory.
- Apply the Cisco‑released patch or upgrade to a non‑vulnerable IOS release.
- Enable detailed HTTP request logging on routers/switches and integrate logs into a SIEM for anomaly detection.
- Incorporate the IOS version check into your continuous asset‑inventory and configuration‑compliance processes.
- Validate that change‑management records capture the patching activity as evidence for audit readiness.
Source: SANS Internet Storm Center – Vulnerability Scans for Older Cisco IOS Vulnerability / Opt‑Out Headers