From 2a49fca09a63ee55827742893ea58e5c5a6b58f7 Mon Sep 17 00:00:00 2001
From: Wouter Jansen <113423245+Wouter-Jansen@users.noreply.github.com>
Date: Tue, 22 Oct 2024 17:32:23 +0200
Subject: [PATCH 1/2] Add missing wildcard to -type parameter

The detection won't hit on e.g. "nslookup.exe -type=MX" without the leading wildcard
---
 detections/endpoint/dns_exfiltration_using_nslookup_app.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/detections/endpoint/dns_exfiltration_using_nslookup_app.yml b/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
index a44266087f..350e300124 100644
--- a/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
+++ b/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
@@ -10,7 +10,7 @@ data_source:
 - Sysmon EventID 1
 - Windows Event Log Security 4688
 - CrowdStrike ProcessRollup2
-search: '| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.process_id) as process_id values(Processes.parent_process) as parent_process count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "nslookup.exe" Processes.process = "*-querytype=*" OR Processes.process="*-qt=*" OR Processes.process="*-q=*" OR Processes.process="-type=*" OR Processes.process="*-retry=*" by Processes.dest Processes.user Processes.process_name Processes.process Processes.parent_process_name  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `dns_exfiltration_using_nslookup_app_filter`'
+search: '| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.process_id) as process_id values(Processes.parent_process) as parent_process count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "nslookup.exe" Processes.process = "*-querytype=*" OR Processes.process="*-qt=*" OR Processes.process="*-q=*" OR Processes.process="*-type=*" OR Processes.process="*-retry=*" by Processes.dest Processes.user Processes.process_name Processes.process Processes.parent_process_name  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `dns_exfiltration_using_nslookup_app_filter`'
 how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
 known_false_positives: admin nslookup usage
 references:

From 7878f7c49b57ad2caa6cef780b88ce50279c3e1a Mon Sep 17 00:00:00 2001
From: Wouter Jansen <113423245+Wouter-Jansen@users.noreply.github.com>
Date: Wed, 23 Oct 2024 09:27:51 +0200
Subject: [PATCH 2/2] Update version, date, and author field

---
 detections/endpoint/dns_exfiltration_using_nslookup_app.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/detections/endpoint/dns_exfiltration_using_nslookup_app.yml b/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
index 350e300124..fd5cd54870 100644
--- a/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
+++ b/detections/endpoint/dns_exfiltration_using_nslookup_app.yml
@@ -1,8 +1,8 @@
 name: DNS Exfiltration Using Nslookup App
 id: 2452e632-9e0d-11eb-bacd-acde48001122
-version: 4
-date: '2024-09-30'
-author: Teoderick Contreras, Splunk
+version: 5
+date: '2024-10-23'
+author: Teoderick Contreras, Splunk, Wouter Jansen
 status: production
 type: TTP
 description: The following analytic identifies potential DNS exfiltration using the nslookup application. It detects specific command-line parameters such as query type (TXT, A, AAAA) and retry options, which are commonly used by attackers to exfiltrate data. The detection leverages Endpoint Detection and Response (EDR) telemetry, focusing on process execution logs. This activity is significant as it may indicate an attempt to communicate with a Command and Control (C2) server or exfiltrate sensitive data. If confirmed malicious, this could lead to data breaches and unauthorized access to critical information.