defense_evasion_communication_apps_suspicious_child_process.toml

[metadata]
bypass_bbr_timing = true
creation_date = "2023/08/04"
integration = ["endpoint"]
maturity = "production"
updated_date = "2024/05/31"

[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
Identifies suspicious child processes of communications apps, which can indicate a potential masquerading as the
communication app or the exploitation of a vulnerability on the application causing it to execute code.
"""
from = "now-9m"
index = ["logs-endpoint.events.process-*"]
language = "eql"
license = "Elastic License v2"
name = "Suspicious Communication App Child Process"
risk_score = 21
rule_id = "adbfa3ee-777e-4747-b6b0-7bd645f30880"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Defense Evasion",
    "Tactic: Persistence",
    "Rule Type: BBR",
    "Data Source: Elastic Defend",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
  (
    /* Slack */
    (process.parent.name : "slack.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Users\\*\\AppData\\Local\\Island\\Island\\Application\\Island.exe",
            "?:\\Users\\*\\AppData\\Roaming\\Zoom\\bin*\\Zoom.exe",
            "?:\\Windows\\System32\\rundll32.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
            "?:\\Windows\\System32\\notepad.exe",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\SysWOW64\\WerFault.exe",
            "?:\\Users\\*\\AppData\\Local\\Programs\\Opera\\opera.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Slack Technologies, Inc.",
            "Slack Technologies, LLC"
          ) and process.code_signature.trusted == true
        ) or
        (
          (process.name : "powershell.exe" and process.command_line : "powershell.exe -c Invoke-WebRequest -Uri https://slackb.com/*") or
          (process.name : "cmd.exe" and process.command_line : "C:\\WINDOWS\\system32\\cmd.exe /d /s /c \"%windir%\\System32\\rundll32.exe User32.dll,SetFocus 0\"")
        )
      )
    ) or

    /* WebEx */
    (process.parent.name : ("CiscoCollabHost.exe", "WebexHost.exe") and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
            "?:\\Users\\*\\AppData\\Local\\Programs\\Opera\\opera.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Cisco Systems, Inc.",
            "Cisco WebEx LLC",
            "Cisco Systems Inc."
          ) and process.code_signature.trusted == true
        )
      )
    ) or

    /* Teams */
    (process.parent.name : "Teams.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\SysWOW64\\WerFault.exe",
            "?:\\Windows\\BrowserCore\\BrowserCore.exe",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Microsoft Corporation",
            "Microsoft 3rd Party Application Component"
          ) and process.code_signature.trusted == true
        ) or
        (
          (process.name : "taskkill.exe" and process.args : "Teams.exe")
        )
      )
    ) or

    /* Discord */
    (process.parent.name : "Discord.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Windows\\System32\\reg.exe",
            "?:\\Windows\\SysWOW64\\reg.exe",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\SysWOW64\\WerFault.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Discord Inc."
          ) and process.code_signature.trusted == true
        ) or
        (
          process.name : "cmd.exe" and 
          (
            process.command_line : (
              "C:\\WINDOWS\\system32\\cmd.exe /d /s /c \"chcp\"",
              "C:\\WINDOWS\\system32\\cmd.exe /q /d /s /c \"C:\\Program^ Files\\NVIDIA^ Corporation\\NVSMI\\nvidia-smi.exe\""
            ) or
            process.args : (
              "C:\\WINDOWS/System32/nvidia-smi.exe",
              "C:\\WINDOWS\\System32\\nvidia-smi.exe",
              "C:\\Windows\\System32\\DriverStore\\FileRepository/*/nvidia-smi.exe*"
            )
          )
        )
      )
    ) or

    /* WhatsApp */
    (process.parent.name : "Whatsapp.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\System32\\reg.exe",
            "?:\\Windows\\SysWOW64\\reg.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "WhatsApp LLC",
            "WhatsApp, Inc",
            "24803D75-212C-471A-BC57-9EF86AB91435"
          ) and process.code_signature.trusted == true
        ) or
        (
          (process.name : "cmd.exe" and process.command_line : "C:\\Windows\\system32\\cmd.exe /d /s /c \"C:\\Windows\\system32\\wbem\\wmic.exe*")
        )
      )
    ) or

    /* Zoom */
    (process.parent.name : "Zoom.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Users\\*\\AppData\\Local\\Island\\Island\\Application\\Island.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
            "?:\\Windows\\System32\\WerFault.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Zoom Video Communications, Inc."
          ) and process.code_signature.trusted == true
        )
      )
    ) or

    /* Outlook */
    (process.parent.name : "outlook.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\SysWOW64\\WerFault.exe",
            "?:\\Windows\\system32\\wermgr.exe",
            "?:\\Users\\*\\AppData\\Local\\Microsoft\\Teams\\current\\Teams.exe",
            "?:\\Users\\*\\AppData\\Local\\Temp\\NewOutlookInstall\\NewOutlookInstaller.exe",
            "?:\\Users\\*\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe",
            "?:\\Users\\*\\AppData\\Local\\Island\\Island\\Application\\Island.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
            "?:\\Users\\*\\AppData\\Roaming\\Zoom\\bin\\Zoom.exe",
            "?:\\Windows\\System32\\IME\\SHARED\\IMEWDBLD.EXE",
            "?:\\Windows\\System32\\spool\\drivers\\x64\\*",
            "?:\\Windows\\System32\\prevhost.exe",
            "?:\\Windows\\System32\\dwwin.exe",
            "?:\\Windows\\System32\\mspaint.exe",
            "?:\\Windows\\SysWOW64\\mspaint.exe",
            "?:\\Windows\\System32\\notepad.exe",
            "?:\\Windows\\SysWOW64\\notepad.exe",
            "?:\\Windows\\System32\\smartscreen.exe",
            "?:\\Windows\\explorer.exe",
            "?:\\Windows\\splwow64.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.name : "rundll32.exe" and
          process.args : "*hpmsn???.dll,MonitorPrintJobStatus*"
        )
      )
    ) or

    /* Thunderbird */
    (process.parent.name : "thunderbird.exe" and not
      (
        (
          process.executable : (
            "?:\\Program Files\\*",
            "?:\\Program Files (x86)\\*",
            "?:\\Windows\\System32\\WerFault.exe",
            "?:\\Windows\\splwow64.exe"
          ) and process.code_signature.trusted == true  
        ) or
        (
          process.code_signature.subject_name : (
            "Mozilla Corporation"
          ) and process.code_signature.trusted == true
        )
      )
    )
  )
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1036"
name = "Masquerading"
reference = "https://attack.mitre.org/techniques/T1036/"
[[rule.threat.technique.subtechnique]]
id = "T1036.001"
name = "Invalid Code Signature"
reference = "https://attack.mitre.org/techniques/T1036/001/"

[[rule.threat.technique.subtechnique]]
id = "T1036.005"
name = "Match Legitimate Name or Location"
reference = "https://attack.mitre.org/techniques/T1036/005/"


[[rule.threat.technique]]
id = "T1055"
name = "Process Injection"
reference = "https://attack.mitre.org/techniques/T1055/"


[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1554"
name = "Compromise Host Software Binary"
reference = "https://attack.mitre.org/techniques/T1554/"


[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"