:warning: THIS IS A EXPERIMENTAL DETECTION

This detection has been marked experimental by the Splunk Threat Research team. This means we have not been able to test, simulate, or build datasets for this detection. Use at your own risk. This analytic is NOT supported.

Try in Splunk Security Cloud

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.

  • Type: TTP

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

  • Last Updated: 2024-05-28
  • Author: Shannon Davis, Splunk
  • ID: babd8d10-d073-11ea-87d0-0242ac130003

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1203 Exploitation for Client Execution Execution
Kill Chain Phase
  • Installation
NIST
  • DE.CM
CIS20
  • CIS 13
CVE 


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

Macros

The SPL above uses the following Macros:

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

Required fields

List of fields required to use this analytic.

  • _time

How To Implement

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

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

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

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

source | version: 2