[metadata]
creation_date = "2020/09/02"
ecs_version = ["1.6.0"]
maturity = "production"
updated_date = "2020/09/02"

[rule]
author = ["Elastic"]
description = """
Identifies network activity from unexpected system applications. This may indicate adversarial activity as these
applications are often leveraged by adversaries to execute code and evade detection.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "winlogbeat-*"]
language = "eql"
license = "Elastic License"
name = "Unusual Network Activity from a Windows System Binary"
risk_score = 21
rule_id = "1fe3b299-fbb5-4657-a937-1d746f2c711a"
severity = "medium"
tags = ["Elastic", "Windows"]
type = "eql"

query = '''
sequence by process.entity_id with maxspan=5m
  [process where event.type in ("start", "process_started") and

     /* known applocker bypasses */
     process.name in ("bginfo.exe",
                      "cdb.exe",
                      "control.exe",
                      "cmstp.exe",
                      "csi.exe",
                      "dnx.exe",
                      "fsi.exe",
                      "ieexec.exe",
                      "iexpress.exe",
                      "installutil.exe",
                      "Microsoft.Workflow.Compiler.exe",
                      "MSBuild.exe",
                      "msdt.exe",
                      "mshta.exe",
                      "msiexec.exe",
                      "msxsl.exe",
                      "odbcconf.exe",
                      "rcsi.exe",
                      "regsvr32.exe",
                      "xwizard.exe")]
  [network where event.type == "connection" and
     process.name in ("bginfo.exe",
                      "cdb.exe",
                      "control.exe",
                      "cmstp.exe",
                      "csi.exe",
                      "dnx.exe",
                      "fsi.exe",
                      "ieexec.exe",
                      "iexpress.exe",
                      "installutil.exe",
                      "Microsoft.Workflow.Compiler.exe",
                      "MSBuild.exe",
                      "msdt.exe",
                      "mshta.exe",
                      "msiexec.exe",
                      "msxsl.exe",
                      "odbcconf.exe",
                      "rcsi.exe",
                      "regsvr32.exe",
                      "xwizard.exe")]
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1127"
name = "Trusted Developer Utilities Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1127/"


[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"