This analytic will identify a suspicious command-line that disables a user account using the native
net1.exe utility to Windows. This technique may used by the adversaries to interrupt availability of accounts and continue the impact against the organization.
- Type: TTP
- Product: Splunk Behavioral Analytics
- Datamodel: Endpoint_Processes
- Last Updated: 2021-11-30
- Author: Teoderick Contreras, Splunk
- ID: ba858b08-d26c-11eb-af9b-acde48001122
|T1078||Valid Accounts||Defense Evasion, Persistence, Privilege Escalation, Initial Access|
1 2 3 4 5 6 | from read_ssa_enriched_events() | eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null) | where cmd_line IS NOT NULL AND like(cmd_line, "%/active:no%") AND like(cmd_line, "%user%") AND (process_name="net1.exe" OR process_name="net.exe") | eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path]) | into write_ssa_detected_events();
The SPL above uses the following Macros:
disable_net_user_account_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
How To Implement
To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where renamed net.exe/net1.exe may be used.
Known False Positives
System administrators or automated scripts may disable an account but not a common practice. Filter as needed.
Associated Analytic story
Kill Chain Phase
|49.0||70||70||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest_device_id$ by user $dest_user_id$ attempting to disable accounts.|
Note that risk score is calculated base on the following formula:
(Impact * Confidence)/100
source | version: 3