Services Escalate Exe
Description
The following analytic identifies the use of svc-exe
with Cobalt Strike. The behavior typically follows after an adversary has already gained initial access and is escalating privileges. Using svc-exe
, a randomly named binary will be downloaded from the remote Teamserver and placed on disk within C:\Windows\400619a.exe
. Following, the binary will be added to the registry under key HKLM\System\CurrentControlSet\Services\400619a\
with multiple keys and values added to look like a legitimate service. Upon loading, services.exe
will spawn the randomly named binary from \\127.0.0.1\ADMIN$\400619a.exe
. The process lineage is completed with 400619a.exe
spawning rundll32.exe, which is the default spawnto_
value for Cobalt Strike. The spawnto_
value is arbitrary and may be any process on disk (typically system32/syswow64 binary). The spawnto_
process will also contain a network connection. During triage, review parallel procesess and identify any additional file modifications.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-07-10
- Author: Michael Haag, Splunk
- ID: c448488c-b7ec-11eb-8253-acde48001122
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=services.exe Processes.process_path=*admin$* by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `services_escalate_exe_filter`
Macros
The SPL above uses the following Macros:
services_escalate_exe_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.dest
- Processes.user
- Processes.parent_process
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_id
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
False positives should be limited as services.exe
should never spawn a process from ADMIN$
. Filter as needed.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
76.0 | 80 | 95 | A service process $parent_process_name$ with process path $process_path$ in host $dest$ |
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://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
- https://attack.mitre.org/techniques/T1548/
- https://hstechdocs.helpsystems.com/manuals/cobaltstrike/current/userguide/index.htm#cshid=1085
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: 1