name: Detect Unauthorized Assets by MAC address
id: dcfd6b40-42f9-469d-a433-2e53f7489ff4
version: 1
date: '2017-09-13'
author: Bhavin Patel, Splunk
type: batch
datamodel:
- Network_Sessions
description: By populating the organization's assets within the assets_by_str.csv,
  we will be able to detect unauthorized devices that are trying to connect with the
  organization's network by inspecting DHCP request packets, which are issued by devices
  when they attempt to obtain an IP address from the DHCP server. The MAC address
  associated with the source of the DHCP request is checked against the list of known
  devices, and reports on those that are not found.
search: '| tstats `security_content_summariesonly` count from datamodel=Network_Sessions
  where nodename=All_Sessions.DHCP All_Sessions.signature=DHCPREQUEST by All_Sessions.src_ip
  All_Sessions.dest_mac | dedup All_Sessions.dest_mac| `drop_dm_object_name("Network_Sessions")`|`drop_dm_object_name("All_Sessions")`
  | search NOT [| inputlookup asset_lookup_by_str |rename mac as dest_mac | fields
  + dest_mac] | `detect_unauthorized_assets_by_mac_address_filter`'
how_to_implement: This search uses the Network_Sessions data model shipped with Enterprise
  Security. It leverages the Assets and Identity framework to populate the assets_by_str.csv
  file located in SA-IdentityManagement, which will contain a list of known authorized
  organizational assets including their MAC addresses. Ensure that all inventoried
  systems have their MAC address populated.
known_false_positives: This search might be prone to high false positives. Please
  consider this when conducting analysis or investigations. Authorized devices may
  be detected as unauthorized. If this is the case, verify the MAC address of the
  system responsible for the false positive and add it to the Assets and Identity
  framework with the proper information.
references: []
tags:
  analytic_story:
  - Asset Tracking
  asset_type: Infrastructure
  cis20:
  - CIS 1
  kill_chain_phases:
  - Reconnaissance
  - Delivery
  - Actions on Objectives
  nist:
  - ID.AM
  - PR.DS
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - All_Sessions.signature
  - All_Sessions.src_ip
  - All_Sessions.dest_mac
  security_domain: network
