Splunk

Cisco Duo Policy Deny Access

Last updated 2 days ago on 2026-07-17

About

The following analytic identifies instances where a Duo administrator creates or updates a policy to explicitly deny user access within the Duo environment. It detects this behavior by searching Duo administrator activity logs for policy creation or update actions where the authentication status is set to "Deny access." By correlating these events with user and admin details, the analytic highlights potential misuse or malicious changes to access policies. This behavior is critical for a SOC to monitor, as unauthorized or suspicious denial of access policies can indicate insider threats, account compromise, or attempts to disrupt legitimate user access. The impact of such an attack may include denial of service to critical accounts, disruption of business operations, or the masking of further malicious activity by preventing targeted users from accessing resources. Early detection enables rapid investigation and remediation to maintain organizational security and availability.
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_administrator` action=policy_update OR action=policy_create | spath input=description | search auth_status="Deny access" | rename object as user | stats count min(_time) as firstTime max(_time) as lastTime BY action actionlabel description user admin_email | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `cisco_duo_policy_deny_access_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).