splunk-security_content/docs/_posts/2020-08-11-detect_rogue_dhcp_server.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Detect Rogue DHCP Server	Hardware Additions, Network Denial of Service, Adversary-in-the-Middle	Network	2020-08-11	true		Hardware Additions Initial Access Network Denial of Service Impact Adversary-in-the-Middle Credential Access Collection Splunk Enterprise Splunk Enterprise Security Splunk Cloud

⚠️ WARNING THIS IS A EXPERIMENTAL DETECTION

We have not been able to test, simulate, or build datasets for this detection. 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
• Datamodel:
• Last Updated: 2020-08-11
• Author: Mikael Bjerkeland, Splunk
• ID: 6e1ada88-7a0d-4ac1-92c6-03d354686079

ATT&CK

ID	Technique	Tactic
T1200	Hardware Additions	Initial Access

| T1498 | Network Denial of Service | Impact |

| T1557 | Adversary-in-the-Middle | Credential Access, Collection |

Search

`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`

Associated Analytic Story

• Router and Infrastructure Security

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.

Required field

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

Kill Chain Phase

• Reconnaissance
• Delivery
• Actions on Objectives

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.

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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