MITRE ATT&CK T1021.002 Windows Admin Share Basic

Severity: low
Type: alert
Author: Google Cloud Security
Source: github.com/chronicle/detection-rules

Detect the use of net use for SMB/Windows admin shares

MITRE ATT&CK coverage

Tactic	Techniques
Lateral Movement	`T1021.002` Remote Services: SMB/Windows Admin Shares

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

// Copyright 2023 Google LLC. Licensed under Apache-2.0.

rule mitre_attack_T1021_002_windows_admin_share_basic {

  meta:
    author = "Google Cloud Security"
    description = "Detect the use of net use for SMB/Windows admin shares"
    rule_id = "mr_ceadd402-7315-4462-9716-8b41a6329bdd"
    rule_name = "MITRE ATT&CK T1021.002 Windows Admin Share Basic"
    tactic = "TA0008"
    technique = "T1021.002"
    type = "alert"
    platform = "Windows"
    data_source = "microsoft sysmon, microsoft windows events"
    severity = "Low"
    priority = "Low"

  events:
    $process.metadata.event_type = "PROCESS_LAUNCH"
    $process.target.process.command_line = /net.*use.*(C|ADMIN|IPC)\$/ nocase

  outcome:
    $risk_score = 35
    // added to populate alert graph with additional context
    $principal_hostname = $process.principal.hostname
    $principal_process_pid = $process.principal.process.pid
    $principal_process_command_line = $process.principal.process.command_line
    $principal_process_file_sha256 = $process.principal.process.file.sha256
    $principal_process_file_full_path = $process.principal.process.file.full_path
    $principal_process_product_specific_process_id = $process.principal.process.product_specific_process_id
    $principal_process_parent_process_product_specific_process_id = $process.principal.process.parent_process.product_specific_process_id
    $target_process_pid = $process.target.process.pid
    $target_process_command_line = $process.target.process.command_line
    $target_process_file_sha256 = $process.target.process.file.sha256
    $target_process_file_full_path = $process.target.process.file.full_path
    $target_process_product_specific_process_id = $process.target.process.product_specific_process_id
    $principal_user_userid = $process.principal.user.userid

  condition:
    $process
}

YARA-L rule structure

Condition

Fires when at least one $process event.

Events

`$process` `PROCESS_LAUNCH` (`1`, `4688`)

target.process.command_line matches "net.*use.*(C|ADMIN|IPC)\$"

Outcome

Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.

Field	Expression
`risk_score`	`35`
`principal_hostname`	`$process.principal.hostname`
`principal_process_pid`	`$process.principal.process.pid`
`principal_process_command_line`	`$process.principal.process.command_line`
`principal_process_file_sha256`	`$process.principal.process.file.sha256`
`principal_process_file_full_path`	`$process.principal.process.file.full_path`
`principal_process_product_specific_process_id`	`$process.principal.process.product_specific_process_id`
`principal_process_parent_process_product_specific_process_id`	`$process.principal.process.parent_process.product_specific_process_id`
`target_process_pid`	`$process.target.process.pid`
`target_process_command_line`	`$process.target.process.command_line`
`target_process_file_sha256`	`$process.target.process.file.sha256`
`target_process_file_full_path`	`$process.target.process.file.full_path`
`target_process_product_specific_process_id`	`$process.target.process.product_specific_process_id`
`principal_user_userid`	`$process.principal.user.userid`