Cisco Smart Install Oversized Packet Detection
This analytic detects oversized Cisco Smart Install (SMI) protocol messages by inspecting traffic to TCP port 4786 within the Network_Traffic data model. Abnormally large SMI payloads have been associated with…
Description
This analytic detects oversized Cisco Smart Install (SMI) protocol messages by inspecting traffic to TCP port 4786 within the Network_Traffic data model. Abnormally large SMI payloads have been associated with exploitation and protocol abuse (e.g., CVE-2018-0171; activity reported by the "Static Tundra" threat actor). Monitoring message sizes over time can help identify possible attempts at remote code execution, denial of service, or reconnaissance against Cisco devices exposing Smart Install.
Detection logic
Detection requirements
- Platform
- ContainersESXiIaaSLinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- splunk_stream_tcp
Known benign triggers
- Legitimate Smart Install operations (e.g., image/config transfers) can produce larger payloads. Baseline typical sizes for your environment and allowlist known management stations when appropriate.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| blog.talosintelligence.com/static-tundra/ | 9 |
| sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-smi2 | 2 |
From the source
- At source
- Open at source
- Upstream identifier
- 3b8d2b4f-4e1e-4a9e-9b43-8a7a3a9c7e21
- Tagged by the source as
- Cisco Smart Install Remote Code Execution CVE-2018-0171NetworknetworkSplunk CloudSplunk EnterpriseSplunk Enterprise Securitynetwork
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1