Memory Dump File with Unusual Extension

[metadata]
bypass_bbr_timing = true
creation_date = "2023/09/21"
integration = ["endpoint"]
maturity = "production"
updated_date = "2024/05/21"

[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
Identifies the creation of a memory dump file with an unusual extension, which can indicate an attempt to disguise a
memory dump as another file type to bypass security defenses.
"""
from = "now-9m"
index = ["logs-endpoint.events.file-*"]
language = "eql"
license = "Elastic License v2"
name = "Memory Dump File with Unusual Extension"
risk_score = 21
rule_id = "c0b9dc99-c696-4779-b086-0d37dc2b3778"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Credential Access",
    "Tactic: Defense Evasion",
    "Data Source: Elastic Defend",
    "Rule Type: BBR",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
file where host.os.type == "windows" and event.type == "creation" and

  /* MDMP header */
  file.Ext.header_bytes : "4d444d50*" and
  not file.extension : ("dmp", "mdmp", "hdmp", "edmp", "full", "tdref", "cg", "tmp", "dat") and
  not 
  (
    process.executable : "?:\\Program Files\\Endgame\\esensor.exe" and
    process.code_signature.trusted == true and length(file.extension) == 0
  ) and
  not
  (
    process.name : "System" and file.extension : "tmpscan"
  )
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1003"
name = "OS Credential Dumping"
reference = "https://attack.mitre.org/techniques/T1003/"
[[rule.threat.technique.subtechnique]]
id = "T1003.001"
name = "LSASS Memory"
reference = "https://attack.mitre.org/techniques/T1003/001/"



[rule.threat.tactic]
id = "TA0006"
name = "Credential Access"
reference = "https://attack.mitre.org/tactics/TA0006/"
[[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 = "T1036.008"
name = "Masquerade File Type"
reference = "https://attack.mitre.org/techniques/T1036/008/"



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