Potential Masquerading as Communication Apps

  1[metadata]
  2creation_date = "2023/05/05"
  3integration = ["endpoint"]
  4maturity = "production"
  5min_stack_comments = "New fields added: required_fields, related_integrations, setup"
  6min_stack_version = "8.3.0"
  7updated_date = "2023/10/13"
  8
  9[rule]
 10author = ["Elastic"]
 11description = """
 12Identifies suspicious instances of communications apps, both unsigned and renamed ones, that can indicate an attempt to
 13conceal malicious activity, bypass security features such as allowlists, or trick users into executing malware.
 14"""
 15from = "now-9m"
 16index = ["logs-endpoint.events.*"]
 17language = "eql"
 18license = "Elastic License v2"
 19name = "Potential Masquerading as Communication Apps"
 20risk_score = 47
 21rule_id = "c9482bfa-a553-4226-8ea2-4959bd4f7923"
 22severity = "medium"
 23tags = ["Domain: Endpoint", "OS: Windows", "Use Case: Threat Detection", "Tactic: Defense Evasion", "Data Source: Elastic Defend"]
 24timestamp_override = "event.ingested"
 25type = "eql"
 26
 27query = '''
 28process where host.os.type == "windows" and
 29  event.type == "start" and
 30  (
 31    /* Slack */
 32    (process.name : "slack.exe" and not
 33      (process.code_signature.subject_name in (
 34        "Slack Technologies, Inc.",
 35        "Slack Technologies, LLC"
 36       ) and process.code_signature.trusted == true)
 37    ) or
 38
 39    /* WebEx */
 40    (process.name : "WebexHost.exe" and not
 41      (process.code_signature.subject_name in ("Cisco WebEx LLC", "Cisco Systems, Inc.") and process.code_signature.trusted == true)
 42    ) or
 43
 44    /* Teams */
 45    (process.name : "Teams.exe" and not
 46      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
 47    ) or
 48
 49    /* Discord */
 50    (process.name : "Discord.exe" and not
 51      (process.code_signature.subject_name == "Discord Inc." and process.code_signature.trusted == true)
 52    ) or
 53
 54    /* RocketChat */
 55    (process.name : "Rocket.Chat.exe" and not
 56      (process.code_signature.subject_name == "Rocket.Chat Technologies Corp." and process.code_signature.trusted == true)
 57    ) or
 58
 59    /* Mattermost */
 60    (process.name : "Mattermost.exe" and not
 61      (process.code_signature.subject_name == "Mattermost, Inc." and process.code_signature.trusted == true)
 62    ) or
 63
 64    /* WhatsApp */
 65    (process.name : "WhatsApp.exe" and not
 66      (process.code_signature.subject_name in (
 67        "WhatsApp LLC",
 68        "WhatsApp, Inc",
 69        "24803D75-212C-471A-BC57-9EF86AB91435"
 70       ) and process.code_signature.trusted == true)
 71    ) or
 72
 73    /* Zoom */
 74    (process.name : "Zoom.exe" and not
 75      (process.code_signature.subject_name == "Zoom Video Communications, Inc." and process.code_signature.trusted == true)
 76    ) or
 77
 78    /* Outlook */
 79    (process.name : "outlook.exe" and not
 80      (process.code_signature.subject_name == "Microsoft Corporation" and process.code_signature.trusted == true)
 81    ) or
 82
 83    /* Thunderbird */
 84    (process.name : "thunderbird.exe" and not
 85      (process.code_signature.subject_name == "Mozilla Corporation" and process.code_signature.trusted == true)
 86    )
 87  )
 88'''
 89
 90
 91[[rule.threat]]
 92framework = "MITRE ATT&CK"
 93[[rule.threat.technique]]
 94id = "T1036"
 95name = "Masquerading"
 96reference = "https://attack.mitre.org/techniques/T1036/"
 97
 98[[rule.threat.technique.subtechnique]]
 99id = "T1036.001"
100name = "Invalid Code Signature"
101reference = "https://attack.mitre.org/techniques/T1036/001/"
102
103[[rule.threat.technique.subtechnique]]
104id = "T1036.005"
105name = "Match Legitimate Name or Location"
106reference = "https://attack.mitre.org/techniques/T1036/005/"
107
108
109[rule.threat.tactic]
110id = "TA0005"
111name = "Defense Evasion"
112reference = "https://attack.mitre.org/tactics/TA0005/"
113
114
115[[rule.threat]]
116framework = "MITRE ATT&CK"
117[[rule.threat.technique]]
118id = "T1554"
119name = "Compromise Client Software Binary"
120reference = "https://attack.mitre.org/techniques/T1554/"
121
122[rule.threat.tactic]
123id = "TA0003"
124name = "Persistence"
125reference = "https://attack.mitre.org/tactics/TA0003/"