Detection: Cisco Duo Policy Allow Old Flash

Updated Date: 2025-07-09 ID: f36c0d3f-d57f-4b88-a5d4-0a4c9a0752f6 Author: Patrick Bareiss, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies instances where a Duo administrator creates or updates a policy to allow the use of outdated Flash components, specifically by detecting policy changes with the flash_remediation=no remediation attribute. It leverages Duo activity logs ingested via the Cisco Security Cloud App, searching for policy_update or policy_create actions and parsing the policy description for indicators of weakened security controls. This behavior is significant for a SOC because permitting old Flash increases the attack surface, as Flash is widely known for its security vulnerabilities and is no longer supported. Attackers may exploit such policy changes to bypass security controls, introduce malware, or escalate privileges within the environment. Detecting and responding to these policy modifications helps prevent potential exploitation, reduces organizational risk, and ensures adherence to security best practices. Immediate investigation is recommended to determine if the change was authorized or indicative of malicious activity.

Search

1`cisco_duo_administrator` action=policy_update OR action=policy_create 
2| spath input=description 
3| search flash_remediation="no remediation" 
4| rename object as user 
5| stats count min(_time) as firstTime max(_time) as lastTime by action actionlabel description user admin_email 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `cisco_duo_policy_allow_old_flash_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_policy_allow_old_flash_filter	`search *`

cisco_duo_policy_allow_old_flash_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 policy has been created or updated to allow old flash by user $user$ with email $admin_email$

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