WARNING THIS IS A EXPERIMENTAL object

We have not been able to test, simulate, or build datasets for this object. Use at your own risk. This analytic is NOT supported.

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Description

By enabling DHCP Snooping as a Layer 2 Security measure on the organization’s network devices, we will be able to detect unauthorized DHCP servers handing out DHCP leases to devices on the network (Man in the Middle attack).

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2020-08-11
  • Author: Mikael Bjerkeland, Splunk
  • ID: 6e1ada88-7a0d-4ac1-92c6-03d354686079

Annotations

ATT&CK
ID Technique Tactic
T1200 Hardware Additions Initial Access
T1498 Network Denial of Service Impact
T1557 Adversary-in-the-Middle Collection, Credential Access
Kill Chain Phase
  • Reconnaissance
  • Delivery
  • Actions on Objectives
NIST
  • ID.AM
  • PR.DS
CIS20
  • CIS 1
  • CIS 11
CVE 
1
2
3
4
5

`cisco_networks` facility="DHCP_SNOOPING" mnemonic="DHCP_SNOOPING_UNTRUSTED_PORT" 
| stats min(_time) AS firstTime max(_time) AS lastTime count values(message_type) AS message_type values(src_mac) AS src_mac BY host 
| `security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)`
| `detect_rogue_dhcp_server_filter`

Macros

The SPL above uses the following Macros:

Note that detect_rogue_dhcp_server_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _time
  • facility
  • mnemonic
  • message_type
  • src_mac
  • host

How To Implement

This search uses a standard SPL query on logs from Cisco Network devices. The network devices must be configured with DHCP Snooping enabled (see https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/security/configuration_guide/b_sec_152ex_2960-x_cg/b_sec_152ex_2960-x_cg_chapter_01101.html) and log with a severity level of minimum “5 - notification”. The search also requires that the Cisco Networks Add-on for Splunk (https://splunkbase.splunk.com/app/1467) is used to parse the logs from the Cisco network devices.

Known False Positives

This search might be prone to high false positives if DHCP Snooping has been incorrectly configured or in the unlikely event that the DHCP server has been moved to another network interface.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

Reference

Test Dataset

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

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