Detection rules › Splunk

Windows Cisco Secure Endpoint Stop Immunet Service Via Sfc

Status
production
Severity
low
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Nasreddine Bencherchali, Splunk
Source
github.com/splunk/security_content

The following analytic detects the use of the sfc.exe utility, in order to stop the Immunet Protect service. The Sfc.exe utility is part of Cisco Secure Endpoint installation. This detection leverages telemetry from the endpoint, focusing on command-line executions involving the -k parameter. This activity is significant as it indicates potential tampering with defensive mechanisms. If confirmed malicious, attackers could partially blind the EDR, enabling further compromise and lateral movement within the network.

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

Rule body splunk

name: Windows Cisco Secure Endpoint Stop Immunet Service Via Sfc
id: 44badcb1-2e8c-4628-9537-021bbae571ad
version: 7
creation_date: '2022-06-17'
modification_date: '2026-05-13'
author: Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: The following analytic detects the use of the `sfc.exe` utility, in order to stop the Immunet Protect service. The Sfc.exe utility is part of Cisco Secure Endpoint installation. This detection leverages telemetry from the endpoint, focusing on command-line executions involving the `-k` parameter. This activity is significant as it indicates potential tampering with defensive mechanisms. If confirmed malicious, attackers could partially blind the EDR, enabling further compromise and lateral movement within the network.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: '| 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="* -k*" AND NOT Processes.process_path IN ("*:\\Windows\\System32\\*", "*:\\Windows\\SysWOW64\\*", ":\\Windows\\WinSxS\\*") by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_cisco_secure_endpoint_stop_immunet_service_via_sfc_filter`'
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: It is possible that this action is executed during troubleshooting activity. Activity needs to be confirmed on a case by case basis.
references:
    - https://www.cisco.com/c/en/us/support/docs/security/amp-endpoints/213690-amp-for-endpoint-command-line-switches.html
drilldown_searches:
    - name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: user
          type: user
          score: 20
          message: Suspicious use of `sfc.exe` stopping the Immunet Protect service on $dest$ by user $user$.
        - field: dest
          type: system
          score: 20
          message: Suspicious use of `sfc.exe` stopping the Immunet Protect service on $dest$ by user $user$.
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
analytic_story:
    - Security Solution Tampering
asset_type: Endpoint
mitre_attack_id:
    - T1685
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.001/cisco_secure_endpoint_tampering/sfc_tampering.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| 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="* -k*" AND NOT Processes.process_path IN ("*:\\Windows\\System32\\*", "*:\\Windows\\SysWOW64\\*", ":\\Windows\\WinSxS\\*") by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `windows_cisco_secure_endpoint_stop_immunet_service_via_sfc_filter`

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Processes.process_pathin"*:\\Windows\\SysWOW64\\*", "*:\\Windows\\System32\\*", ":\\Windows\\WinSxS\\*"

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.processeq
  • "* -k*"
Processes.process_nameeq
  • "sfc.exe" corpus 4 (splunk 3, elastic 1)