Detection rules › Elastic
Memory Dump File with Unusual Extension
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.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1036.008 Masquerading: Masquerade File Type |
| Credential Access | T1003.001 OS Credential Dumping: LSASS Memory |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 11 | FileCreate |
Rule body elastic
[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/"
Stages and Predicates
Stage 1: file
file where host.os.type == "windows" and event.type == "creation" and
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"
)
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
file.extension | eq | tmpscan |
process.name | eq | System |
file.extension | length_compare | ==, 0 |
process.code_signature.trusted | eq | true |
process.executable | eq | ?:\Program Files\Endgame\esensor.exe |
file.extension | eq | dmp, mdmp, hdmp, edmp, full, tdref, cg, tmp, dat |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
event.type | eq |
|
file.Ext.header_bytes | wildcard |
|