sigma-rules/rules/windows/command_and_control_iexplore_via_com.toml

[metadata]
creation_date = "2020/11/28"
maturity = "production"
updated_date = "2022/02/14"

[rule]
author = ["Elastic"]
description = """
Identifies instances of Internet Explorer (iexplore.exe) being started via the Component Object Model (COM) making
unusual network connections. Adversaries could abuse Internet Explorer via COM to avoid suspicious processes making
network connections and bypass host-based firewall restrictions.
"""
false_positives = ["Processes such as MS Office using IEproxy to render HTML content."]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Potential Command and Control via Internet Explorer"
risk_score = 47
rule_id = "acd611f3-2b93-47b3-a0a3-7723bcc46f6d"
severity = "medium"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Command and Control"]
type = "eql"

query = '''
sequence by host.id, user.name with maxspan = 5s
  [library where dll.name : "IEProxy.dll" and process.name : ("rundll32.exe", "regsvr32.exe")]
  [process where event.type == "start" and process.parent.name : "iexplore.exe" and process.parent.args : "-Embedding"]
  /* IE started via COM in normal conditions makes few connections, mainly to Microsoft and OCSP related domains, add FPs here */
  [network where network.protocol == "dns" and process.name : "iexplore.exe" and
   not dns.question.name :
   (
    "*.microsoft.com",
    "*.digicert.com",
    "*.msocsp.com",
    "*.windowsupdate.com",
    "*.bing.com",
    "*.identrust.com",
    "*.sharepoint.com",
    "*.office365.com",
    "*.office.com"
    )
  ] /* with runs=5 */
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1071"
name = "Application Layer Protocol"
reference = "https://attack.mitre.org/techniques/T1071/"


[rule.threat.tactic]
id = "TA0011"
name = "Command and Control"
reference = "https://attack.mitre.org/tactics/TA0011/"

[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1559"
name = "Inter-Process Communication"
reference = "https://attack.mitre.org/techniques/T1559/"

  [[rule.threat.technique.subtechnique]]
  id = "T1559.001"
  name = "Component Object Model"
  reference = "https://attack.mitre.org/techniques/T1559/001/"

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