defense_evasion_masquerading_business_apps_installer.toml

[metadata]
creation_date = "2023/09/01"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/10/13"
bypass_bbr_timing = true

[rule]
author = ["Elastic"]
description = """
Identifies executables with names resembling legitimate business applications but lacking signatures from the original
developer. Attackers may trick users into downloading malicious executables that masquerade as legitimate applications
via malicious ads, forum posts, and tutorials, effectively gaining initial access.
"""
from = "now-9m"
index = ["logs-endpoint.events.*"]
language = "eql"
license = "Elastic License v2"
name = "Potential Masquerading as Business App Installer"
references = [
    "https://www.rapid7.com/blog/post/2023/08/31/fake-update-utilizes-new-idat-loader-to-execute-stealc-and-lumma-infostealers",
]
risk_score = 21
rule_id = "feafdc51-c575-4ed2-89dd-8e20badc2d6c"
severity = "low"
tags = ["Domain: Endpoint", "Data Source: Elastic Defend", "OS: Windows", "Use Case: Threat Detection", "Tactic: Defense Evasion", "Tactic: Initial Access", "Tactic: Execution", "Rule Type: BBR"]
timestamp_override = "event.ingested"
building_block_type = "default"
type = "eql"

query = '''
process where host.os.type == "windows" and
  event.type == "start" and process.executable : "?:\\Users\\*\\Downloads\\*" and
  not process.code_signature.status : ("errorCode_endpoint*", "errorUntrustedRoot", "errorChaining") and
  (
    /* Slack */
    (process.name : "*slack*.exe" and not
      (process.code_signature.subject_name in (
        "Slack Technologies, Inc.",
        "Slack Technologies, LLC"
       ) and process.code_signature.trusted == true)
    ) or

    /* WebEx */
    (process.name : "*webex*.exe" and not
      (process.code_signature.subject_name in ("Cisco WebEx LLC", "Cisco Systems, Inc.") and process.code_signature.trusted == true)
    ) or

    /* Teams */
    (process.name : "teams*.exe" and not
      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
    ) or

    /* Discord */
    (process.name : "*discord*.exe" and not
      (process.code_signature.subject_name == "Discord Inc." and process.code_signature.trusted == true)
    ) or

    /* WhatsApp */
    (process.name : "*whatsapp*.exe" and not
      (process.code_signature.subject_name in (
        "WhatsApp LLC",
        "WhatsApp, Inc",
        "24803D75-212C-471A-BC57-9EF86AB91435"
       ) and process.code_signature.trusted == true)
    ) or

    /* Zoom */
    (process.name : ("*zoom*installer*.exe", "*zoom*setup*.exe", "zoom.exe")  and not
      (process.code_signature.subject_name == "Zoom Video Communications, Inc." and process.code_signature.trusted == true)
    ) or

    /* Outlook */
    (process.name : "*outlook*.exe" and not
      (
        (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true) or
        (
          process.name: "MSOutlookHelp-PST-Viewer.exe" and process.code_signature.subject_name == "Aryson Technologies Pvt. Ltd" and
          process.code_signature.trusted == true
        )
      )
    ) or

    /* Thunderbird */
    (process.name : "*thunderbird*.exe" and not
      (process.code_signature.subject_name == "Mozilla Corporation" and process.code_signature.trusted == true)
    ) or

    /* Grammarly */
    (process.name : "*grammarly*.exe" and not
      (process.code_signature.subject_name == "Grammarly, Inc." and process.code_signature.trusted == true)
    ) or

    /* Dropbox */
    (process.name : "*dropbox*.exe" and not
      (process.code_signature.subject_name == "Dropbox, Inc" and process.code_signature.trusted == true)
    ) or

    /* Tableau */
    (process.name : "*tableau*.exe" and not
      (process.code_signature.subject_name == "Tableau Software LLC" and process.code_signature.trusted == true)
    ) or

    /* Google Drive */
    (process.name : "*googledrive*.exe" and not
      (process.code_signature.subject_name == "Google LLC" and process.code_signature.trusted == true)
    ) or

    /* MSOffice */
    (process.name : "*office*setup*.exe" and not
      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
    ) or

    /* Okta */
    (process.name : "*okta*.exe" and not
      (process.code_signature.subject_name == "Okta, Inc." and process.code_signature.trusted == true)
    ) or

    /* OneDrive */
    (process.name : "*onedrive*.exe" and not
      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
    ) or

    /* Chrome */
    (process.name : "*chrome*.exe" and not
      (process.code_signature.subject_name in ("Google LLC", "Google Inc") and process.code_signature.trusted == true)
    ) or

    /* Firefox */
    (process.name : "*firefox*.exe" and not
      (process.code_signature.subject_name == "Mozilla Corporation" and process.code_signature.trusted == true)
    ) or

    /* Edge */
    (process.name : ("*microsoftedge*.exe", "*msedge*.exe") and not
      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
    ) or

    /* Brave */
    (process.name : "*brave*.exe" and not
      (process.code_signature.subject_name == "Brave Software, Inc." and process.code_signature.trusted == true)
    ) or

    /* GoogleCloud Related Tools */
    (process.name : "*GoogleCloud*.exe" and not
      (process.code_signature.subject_name == "Google LLC" and process.code_signature.trusted == true)
    ) or

    /* Github Related Tools */
    (process.name : "*github*.exe" and not
      (process.code_signature.subject_name == "GitHub, Inc." and process.code_signature.trusted == true)
    ) or

    /* Notion */
    (process.name : "*notion*.exe" and not
      (process.code_signature.subject_name == "Notion Labs, Inc." 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.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"

[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1189"
name = "Drive-by Compromise"
reference = "https://attack.mitre.org/techniques/T1189/"


[rule.threat.tactic]
id = "TA0001"
name = "Initial Access"
reference = "https://attack.mitre.org/tactics/TA0001/"

[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1204"
name = "User Execution"
reference = "https://attack.mitre.org/techniques/T1204/"
[[rule.threat.technique.subtechnique]]
id = "T1204.002"
name = "Malicious File"
reference = "https://attack.mitre.org/techniques/T1204/002/"



[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"