Splunk

Cisco Duo Admin Login Unusual Os

Last updated 2 days ago on 2026-07-17

About

The following analytic identifies Duo admin login attempts from operating systems that are unusual for your environment, excluding commonly used OS such as Mac OS X. Please adjust to your environment. It works by analyzing Duo activity logs for admin login actions and filtering out logins from expected operating systems. The analytic then aggregates events by browser, version, source IP, location, and OS details to highlight anomalies. Detecting admin logins from unexpected operating systems is critical for a SOC, as it may indicate credential compromise, unauthorized access, or attacker activity using unfamiliar devices. Such behavior can precede privilege escalation, policy changes, or other malicious actions within the Duo environment. Early detection enables rapid investigation and response, reducing the risk of account takeover and minimizing potential damage to organizational security controls.
Platform
Splunk
Tags
Data Source: SplunkDomain: ApplicationRule Type: QueryOS: Any
Severity
medium
Risk Score
47
References
https://splunkbase.splunk.com/app/7404(external, opens in a new tab or window)
False Positives
No false positives have been identified at this time.
Source
View on GitHub(external, opens in a new tab or window)

Definition

Rule Language
SPL
Rule Type
query
text code block:
`cisco_duo_activity` "action.name"=admin_login NOT access_device.os IN ("Mac OS X") | rename actor.name as user access_device.ip.address as src_ip | stats count min(_time) as firstTime max(_time) as lastTime BY access_device.browser access_device.browser_version src_ip access_device.location.city access_device.location.country access_device.location.state access_device.os access_device.os_version actor.details actor.type outcome.result user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `cisco_duo_admin_login_unusual_os_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).