Cisco IOS XE WebUI Login From IOSd Local Port
Last updated 2 days ago on 2026-07-17
About
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.
- Platform
Splunk
- Tags
- Data Source: SplunkDomain: ApplicationRule Type: QueryOS: Any
- Severity
- medium
- Risk Score
- 47
- References
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa25-239a(external, opens in a new tab or window)https://blog.talosintelligence.com/salt-typhoon-analysis/(external, opens in a new tab or window)
- False Positives
- This local port value should not appear for normal WebUI logins. So false positives should very minimal.
- Source
- View on GitHub(external, opens in a new tab or window)
Definition
- Rule Language
- SPL
- Rule Type
- query
text code block:`cisco_ios` facility="SEC_LOGIN" mnemonic IN ("QUIET_MODE_ON", "LOGIN_SUCCESS", "LOGIN_FAILED") message_text="*[localport: 21111]*" | rex field=_raw "\[user:\s*(?<user>[^\]]+)\]" | rex field=_raw "\[Source:\s*(?<src_ip>[^\]]+)\]" | rex field=_raw "\[localport:\s*(?<local_port>[^\]]+)\]" | rex field=_raw "\[Reason:\s*(?<reason>[^\]]+)\]" | rex field=_raw "\[ACL:\s*(?<acl>[^\]]+)\]" | eval dest=coalesce(host, dvc, dest, "unknown") | stats count min(_time) as firstTime max(_time) as lastTime values(local_port) as local_port values(acl) as acl by dest user src_ip reason | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `cisco_ios_xe_webui_login_from_iosd_local_port_filter`
View this rule on Splunk
This rule was sourced from the official Splunk public repository. View the original rule on GitHub(external, opens in a new tab or window).