Detection: BITS Job Persistence

Description

The following analytic detects the use of bitsadmin.exe to schedule a BITS job for persistence on an endpoint. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line parameters such as create, addfile, and resume. This activity is significant because BITS jobs can be used by attackers to maintain persistence, download malicious payloads, or exfiltrate data. If confirmed malicious, this could allow an attacker to persist in the environment, execute arbitrary code, or transfer sensitive information, necessitating further investigation and potential remediation.

Search

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_bitsadmin` Processes.process IN (*create*, *addfile*, *setnotifyflags*, *setnotifycmdline*, *setminretrydelay*, *setcustomheaders*, *resume* ) by Processes.dest Processes.user Processes.original_file_name Processes.parent_process Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `bits_job_persistence_filter`

Data Source

Name	Platform	Sourcetype	Source
CrowdStrike ProcessRollup2	N/A	'crowdstrike:events:sensor'	'crowdstrike'
Sysmon EventID 1	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688	Windows	'xmlwineventlog'	'XmlWinEventLog:Security'

Macros Used

Annotations

Default Configuration

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

Implementation

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

Limited false positives will be present. Typically, applications will use BitsAdmin.exe. Any filtering should be done based on command-line arguments (legitimate applications) or parent process.

Associated Analytic Story

• BITS Jobs

• Living Off The Land

Risk Based Analytics (RBA)

References

• https://attack.mitre.org/techniques/T1197/

• https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/bitsadmin

• https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1197/T1197.md#atomic-test-3---persist-download--execute

• https://lolbas-project.github.io/lolbas/Binaries/Bitsadmin/

Detection Testing

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: 5