sigma-rules/rules/windows/credential_access_iis_connectionstrings_dumping.toml

[metadata]
creation_date = "2020/08/18"
integration = ["endpoint", "windows"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/02/22"

[rule]
author = ["Elastic"]
description = """
Identifies use of aspnet_regiis to decrypt Microsoft IIS connection strings. An attacker with Microsoft IIS web server
access via a webshell or alike can decrypt and dump any hardcoded connection strings, such as the MSSQL service account
password using aspnet_regiis command.
"""
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*", "endgame-*"]
language = "eql"
license = "Elastic License v2"
max_signals = 33
name = "Microsoft IIS Connection Strings Decryption"
note = """## Setup

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
"""
references = [
    "https://blog.netspi.com/decrypting-iis-passwords-to-break-out-of-the-dmz-part-1/",
    "https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/greenbug-espionage-telco-south-asia",
]
risk_score = 73
rule_id = "c25e9c87-95e1-4368-bfab-9fd34cf867ec"
severity = "high"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Credential Access", "Elastic Endgame"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
  (process.name : "aspnet_regiis.exe" or process.pe.original_file_name == "aspnet_regiis.exe") and
  process.args : "connectionStrings" and process.args : "-pdf"
'''


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


[rule.threat.tactic]
id = "TA0006"
name = "Credential Access"
reference = "https://attack.mitre.org/tactics/TA0006/"