CmdID

CmdID / Rules / Windows

Cmd Launched with Hidden Start Flags to Suspicious Targets

A Sigma rule for process creation on Windows, by Vladan Sekulic, Swachchhanda Shrawan Poudel (Nextron Systems).

medium 1 ATT&CK technique 1 program it names

What it looks for

its detection, as SigmaHQ writes it
detection:
  selection_cli_susp_extension:
    CommandLine|contains:
      - '.bat'
      - '.cmd'
      - '.cpl'
      - '.hta'
      - '.js'
      - '.ps1'
      - '.scr'
      - '.vbe'
      - '.vbs'
  selection_cli_susp_pattern:
    CommandLine|contains:
      - ' -nop '
      - ' -sta '
      - '.downloadfile('
      - '.downloadstring('
      - '-noni '
      - '-w hidden '
  selection_cli_uncommon_location:
    CommandLine|contains:
      - ':\Perflogs\'
      - ':\Temp\'
      - ':\Users\Default\'
      - ':\Windows\Temp\'
      - '\AppData\Roaming\'
      - '\Contacts\'
      - '\Documents\'
      - '\Downloads\'
      - '\Favorites\'
      - '\Favourites\'
      - '\inetpub\'
      - '\Music\'
      - '\Photos\'
      - '\Temporary Internet\'
      - '\Users\Public\'
      - '\Videos\'
  selection_cmd_hidden_start_1:
    CommandLine|contains|windash:
      - 'start '
      - 'start/b'
      - 'start/min'
  selection_cmd_hidden_start_2:
    CommandLine|contains|windash:
      - '/b '
      - '/b"'
      - '/min '
      - '/min"'
  selection_cmd_img:
    - Image|endswith: '\cmd.exe'
    - OriginalFileName: 'Cmd.Exe'
  condition: all of selection_cmd_* and 1 of selection_cli_*

The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Vladan Sekulic, Swachchhanda Shrawan Poudel (Nextron Systems), under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.

None of the everyday examples and documented commands on CmdID’s program pages trips it. To see whether a command line does, paste it into CmdID.

Programs and files it names

their pages here

ATT&CK

the techniques it is tagged with
T1564.003Hide Artifacts: Hidden Window