Cisco Duo - Block IP

Entities: User, IP Log type: Cisco Duo

Playbook Description

It adds the flagged user to a designated group via a sub‑playbook ("Duo - Add User to Group"), then ensures a Duo policy blocks the offending IP address — either by updating an existing block list or creating a new one if none exists yet.

MITRE D3FEND mapping

Tactics Techniques Sub-techniques
Isolate (D3 - Isolate) D3 - NI Network Traffic Filtering (D3 - NTF)

Playbook input type

Alert

Prerequisites

  • Cisco Duo configuration - Need to connect Cisco Duo using HMAC connection with Integration and secret key.

Dependencies

Extensions - Cisco Duo

  • ciscoduo_updatePolicy
  • ciscoduo_createPolicy
  • ciscoduo_retrievePolicies
  • ciscoduo_retrievePolicyById

Utility functions:

  • utility_extractFieldFromList
  • utility_appendValues
  • utility_filterAndMatchEvents

Connections

Cisco Duo connection - Need to connect Cisco Duo using Integration Key, Secret Key and API Hostname.

Sub playbooks

  • Cisco Duo - Add user to group

Execution workflow

Investigation:

  • Executes the "Cisco Duo - Add user to group" sub-playbook.

Decision logic:

  • Proceeds to remediation based on the following conditions:
    • Related investigation findings are present.
  • If no malicious indicators are confirmed, the playbook ends with no further actions.

Remediation:

  • Retrieves all policies.
  • Checks if the block IP policy already exists.
  • Checks whether policy exists.
  • Builds the policy section.
  • Creates the block IP policy.
Execution Workflow
Figure: Execution workflow of the playbook

Post execution procedure

  • Review the blocked IP address to ensure no legitimate traffic was affected.
  • Verify that the block IP policy was successfully created or updated in Cisco Duo.
  • Monitor for any bypass attempts from alternate IP addresses by the same threat actor.
  • Review the IP block policy periodically and remove entries that are no longer relevant.
  • Investigate the source of the blocked IP for additional threat intelligence.