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Potential Masquerading as Communication Apps

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Potential Masquerading as Communication Apps

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Identifies suspicious instances of communications apps, both unsigned and renamed ones, that can indicate an attempt to conceal malicious activity, bypass security features such as allowlists, or trick users into executing malware.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: medium

Risk score: 47

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
Data Source: Elastic Defend

Version: 4

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.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 : "WebexHost.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

    /* RocketChat */
    (process.name : "Rocket.Chat.exe" and not
      (process.code_signature.subject_name == "Rocket.Chat Technologies Corp." and process.code_signature.trusted == true)
    ) or

    /* Mattermost */
    (process.name : "Mattermost.exe" and not
      (process.code_signature.subject_name == "Mattermost, 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.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

    /* Thunderbird */
    (process.name : "thunderbird.exe" and not
      (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/
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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