Change To Safe Mode With Network Config
Description
The following analytic detects the execution of a suspicious bcdedit
command that configures a host to boot in safe mode with network support. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving bcdedit.exe
with specific parameters. This activity is significant because it is a known technique used by BlackMatter ransomware to force a compromised host into safe mode for continued encryption. If confirmed malicious, this could allow attackers to bypass certain security controls, persist in the environment, and continue their malicious activities.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2024-05-26
- Author: Teoderick Contreras, Splunk
- ID: 81f1dce0-0f18-11ec-a5d7-acde48001122
Annotations
Kill Chain Phase
- Actions On Objectives
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = bcdedit.exe Processes.process="*/set*" Processes.process="*{current}*" Processes.process="*safeboot*" Processes.process="*network*" by Processes.process_name Processes.process Processes.parent_process_name Processes.dest Processes.user
|`drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `change_to_safe_mode_with_network_config_filter`
Macros
The SPL above uses the following Macros:
change_to_safe_mode_with_network_config_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
- Processes.process_name
- Processes.process
- Processes.parent_process_name
- Processes.parent_process
- Processes.dest
- Processes.user
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
unknown
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
25.0 | 50 | 50 | bcdedit process with commandline $process$ to force safemode boot the $dest$ |
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
- https://news.sophos.com/en-us/2021/08/09/blackmatter-ransomware-emerges-from-the-shadow-of-darkside/
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