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Suspicious Communication App Child Process

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Suspicious Communication App Child Process

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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.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Domain: Endpoint
OS: Windows
Use Case: Threat Detection
Tactic: Defense Evasion
Tactic: Persistence
Rule Type: BBR
Data Source: Elastic Defend

Version: 2

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

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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\\Roaming\\Zoom\\bin\\Zoom.exe",
            "?:\\Windows\\System32\\rundll32.exe",
            "?:\\Users\\*\\AppData\\Local\\Mozilla Firefox\\firefox.exe",
            "?:\\Windows\\System32\\notepad.exe",
            "?:\\Windows\\System32\\WerFault.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"
          ) 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"
          ) 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)\\*",
            "?:\\Windows\\System32\\reg.exe",
            "?:\\Windows\\SysWOW64\\reg.exe",
            "?:\\Windows\\System32\\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

    /* 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",
            "?:\\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",
            "?:\\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\\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\\notepad.exe",
            "?:\\Windows\\explorer.exe"
          ) and process.code_signature.trusted == true
        )
      )
    ) or

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

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Masquerading
- ID: T1036
- Reference URL: https://attack.mitre.org/techniques/T1036/
Sub-technique:
- Name: Invalid Code Signature
- ID: T1036.001
- Reference URL: https://attack.mitre.org/techniques/T1036/001/
Sub-technique:
- Name: Match Legitimate Name or Location
- ID: T1036.005
- Reference URL: https://attack.mitre.org/techniques/T1036/005/
Technique:
- Name: Process Injection
- ID: T1055
- Reference URL: https://attack.mitre.org/techniques/T1055/
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Compromise Client Software Binary
- ID: T1554
- Reference URL: https://attack.mitre.org/techniques/T1554/

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