Detection: Detect Windows DNS SIGRed via Splunk Stream

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-08-14 ID: babd8d10-d073-11ea-87d0-0242ac130003 Author: Shannon Davis, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects attempts to exploit the SIGRed vulnerability (CVE-2020-1350) in Windows DNS servers. It leverages Splunk Stream DNS and TCP data to identify DNS SIG and KEY records, as well as TCP payloads exceeding 65KB. This activity is significant because SIGRed is a critical wormable vulnerability that allows remote code execution. If confirmed malicious, an attacker could gain unauthorized access, execute arbitrary code, and potentially disrupt services, leading to severe data breaches and infrastructure compromise. Immediate investigation and remediation are crucial to mitigate these risks.

Search

 1`stream_dns` 
 2| spath "query_type{}" 
 3| search "query_type{}" IN (SIG,KEY) 
 4| spath protocol_stack 
 5| search protocol_stack="ip:tcp:dns" 
 6| append [search `stream_tcp` bytes_out>65000] 
 7| `detect_windows_dns_sigred_via_splunk_stream_filter` 
 8| stats count by flow_id 
 9| where count>1 
10| fields - count

Data Source

Name	Platform	Sourcetype	Source	Supported App
N/A	N/A	N/A	N/A	N/A

Macros Used

Name	Value
stream_dns	`sourcetype=stream:dns`
detect_windows_dns_sigred_via_splunk_stream_filter	`search *`

detect_windows_dns_sigred_via_splunk_stream_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1203	Exploitation for Client Execution	Execution

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_13

APT12

APT28

APT29

APT3

APT32

APT33

APT37

APT41

Andariel

Aoqin Dragon

Axiom

BITTER

BRONZE BUTLER

BlackTech

Cobalt Group

Confucius

Darkhotel

Dragonfly

EXOTIC LILY

Elderwood

Ember Bear

Higaisa

Inception

Lazarus Group

Leviathan

MuddyWater

Mustang Panda

Patchwork

Sandworm Team

Sidewinder

TA459

The White Company

Threat Group-3390

Tonto Team

Transparent Tribe

Tropic Trooper

admin@338

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

You must be ingesting Splunk Stream DNS and Splunk Stream TCP. We are detecting SIG and KEY records via stream:dns and TCP payload over 65KB in size via stream:tcp. Replace the macro definitions ('stream:dns' and 'stream:tcp') with configurations for your Splunk environment.

Known False Positives

unknown

Associated Analytic Story

Windows DNS SIGRed CVE-2020-1350

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
tbd	25	50	50

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	N/A	`N/A`	`N/A`

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

Source: GitHub | Version: 3