Detection: Cisco Duo Bulk Policy Deletion

Updated Date: 2025-07-10 ID: 983be012-e408-4cb0-b87f-6756bb5f7047 Author: Patrick Bareiss, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects instances where a Duo administrator performs a bulk deletion of more than three policies in a single action. It identifies this behavior by searching Duo activity logs for the policy_bulk_delete action, extracting the names of deleted policies, and counting them. If the count exceeds three, the event is flagged. This behavior is significant for a Security Operations Center (SOC) because mass deletion of security policies can indicate malicious activity, such as an attacker or rogue administrator attempting to weaken or disable security controls, potentially paving the way for further compromise. Detecting and investigating such actions promptly is critical, as the impact of this attack could include reduced security posture, increased risk of unauthorized access, and potential data breaches. Monitoring for bulk policy deletions helps ensure that any suspicious or unauthorized changes to security configurations are quickly identified and addressed to protect organizational assets and maintain compliance.

Search

 1`cisco_duo_administrator` action=policy_bulk_delete 
 2| rename username as user 
 3| spath input=description 
 4| rex field=policies max_match=0 "(?<policy_name>[^:,]+):\s+" 
 5| eval policy_count=mvcount(policy_name) 
 6| where policy_count > 3 
 7| stats count min(_time) as firstTime max(_time) as lastTime by action actionlabel description user admin_email policy_count 
 8| `security_content_ctime(firstTime)` 
 9| `security_content_ctime(lastTime)` 
10| `cisco_duo_bulk_policy_deletion_filter`

Data Source

Name	Platform	Sourcetype	Source
Cisco Duo Administrator	N/A	`'cisco:duo:administrator'`	`'cisco_duo'`

Macros Used

Name	Value
cisco_duo_administrator	`sourcetype=cisco:duo:administrator`
cisco_duo_bulk_policy_deletion_filter	`search *`

cisco_duo_bulk_policy_deletion_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1556	Modify Authentication Process	Credential Access

Exploitation

Installation

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

The analytic leverages Duo activity logs to be ingested using the Cisco Security Cloud App (https://splunkbase.splunk.com/app/7404).

Known False Positives

unknown

Associated Analytic Story

Cisco Duo Suspicious Activity

Risk Based Analytics (RBA)

Risk Message:

A user $user$ has deleted more than 3 policies

Risk Object	Risk Object Type	Risk Score	Threat Objects
user	user	48	No Threat Objects

References

https://splunkbase.splunk.com/app/7404

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`duo`	`cisco:duo:administrator`
Integration	✅ Passing	Dataset	`duo`	`cisco:duo:administrator`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1