Cisco IOS XE WebUI Login From IOSd Local Port
This analytic detects Cisco IOS-XE WebUI authentication failure and success logs that include local port 21111. This is a strong an indicator of WebUI exploitation because normal users should not authenticate through…
Description
This analytic detects Cisco IOS-XE WebUI authentication failure and success logs that include local port 21111. This is a strong an indicator of WebUI exploitation because normal users should not authenticate through the underlying IOS-XE Linux shell path.
Detection logic
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- cisco_ios_logs
Known benign triggers
- This local port value should not appear for normal WebUI logins. So false positives should very minimal.
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/salt-typhoon-analysis/ | 9 |
| www.cisa.gov/news-events/cybersecurity-advisories/aa25-239a | 14 |
From the source
- At source
- Open at source
- Upstream identifier
- 77a1751f-552f-456c-b9ae-cdb66eec3e42
- Tagged by the source as
- Salt TyphoonNetworkapplicationSplunk 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