Detection: Windows Cisco Secure Endpoint Uninstall Immunet Service Via Sfc

Updated Date: 2025-02-19 ID: ba6e7f4d-a85e-4a14-8e7d-41f4b82e3c9a Author: Nasreddine Bencherchali, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects the use of the sfc.exe utility with the "-u" parameter, which is part of the Cisco Secure Endpoint installation. The "-u" flag allows the uninstallation of Cisco Secure Endpoint components. This detection leverages endpoint telemetry to monitor command-line executions that include the "-u" parameter. The use of this flag is significant as it could indicate an attempt to disable or remove endpoint protection, potentially leaving the system vulnerable to further exploitation. If identified as malicious, this action may be part of a broader effort to disable security mechanisms and avoid detection.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name="sfc.exe" Processes.process="* -u*" NOT Processes.process="* -unblock *" AND NOT Processes.process_path IN ("*:\\Windows\\System32\\*", "*:\\Windows\\SysWOW64\\*", ":\\Windows\\WinSxS\\*") by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.parent_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| `windows_cisco_secure_endpoint_uninstall_immunet_service_via_sfc_filter`

Data Source

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

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_cisco_secure_endpoint_uninstall_immunet_service_via_sfc_filter search *
windows_cisco_secure_endpoint_uninstall_immunet_service_via_sfc_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
T1562.001 Disable or Modify Tools Defense Evasion
Exploitation
DE.AE
CIS 10

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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

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

It is possible that this action is executed during troubleshooting activity. Activity needs to be confirmed on a case by case basis.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Suspicious use of sfc.exe to uninstall the Immunet Protect service on $dest$ by user $user$.

Risk Object Risk Object Type Risk Score Threat Objects
user user 56 parent_process_name, process_name
dest system 56 parent_process_name, process_name

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog

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: 1