Detection rules › Elastic
Accessing Outlook Data Files
Identifies commands containing references to Outlook data files extensions, which can potentially indicate the search, access, or modification of these files.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Collection | T1005 Data from Local System, T1114.001 Email Collection: Local Email Collection |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body elastic
[metadata]
creation_date = "2023/08/21"
integration = ["endpoint", "windows", "system"]
maturity = "production"
updated_date = "2026/03/24"
[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
Identifies commands containing references to Outlook data files extensions, which can potentially indicate the search,
access, or modification of these files.
"""
from = "now-119m"
index = [
"endgame-*",
"logs-endpoint.events.process-*",
"logs-system.security*",
"logs-windows.sysmon_operational-*",
"winlogbeat-*",
]
interval = "60m"
language = "eql"
license = "Elastic License v2"
name = "Accessing Outlook Data Files"
risk_score = 21
rule_id = "2e311539-cd88-4a85-a301-04f38795007c"
severity = "low"
tags = [
"Domain: Endpoint",
"OS: Windows",
"Use Case: Threat Detection",
"Tactic: Collection",
"Data Source: Elastic Defend",
"Rule Type: BBR",
"Data Source: Sysmon",
"Data Source: Elastic Endgame",
"Data Source: Windows Security Event Logs",
]
timestamp_override = "event.ingested"
type = "eql"
query = '''
process where host.os.type == "windows" and event.type == "start" and process.args : ("*.ost", "*.pst") and
not process.name : "outlook.exe" and
not (
process.name : "rundll32.exe" and
process.args : "*davclnt.dll,DavSetCookie*"
)
'''
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1005"
name = "Data from Local System"
reference = "https://attack.mitre.org/techniques/T1005/"
[[rule.threat.technique]]
id = "T1114"
name = "Email Collection"
reference = "https://attack.mitre.org/techniques/T1114/"
[[rule.threat.technique.subtechnique]]
id = "T1114.001"
name = "Local Email Collection"
reference = "https://attack.mitre.org/techniques/T1114/001/"
[rule.threat.tactic]
id = "TA0009"
name = "Collection"
reference = "https://attack.mitre.org/tactics/TA0009/"
Stages and Predicates
Stage 1: process
process where host.os.type == "windows" and event.type == "start" and process.args : ("*.ost", "*.pst") and
not process.name : "outlook.exe" and
not (
process.name : "rundll32.exe" and
process.args : "*davclnt.dll,DavSetCookie*"
)
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
process.args | match | davclnt.dll,DavSetCookie |
process.name | eq | rundll32.exe |
process.name | eq | outlook.exe |
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 |
|
process.args | wildcard |
|