[metadata]
creation_date = "2020/08/18"
maturity = "production"
updated_date = "2021/03/03"

[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.*"]
language = "eql"
license = "Elastic License v2"
max_signals = 33
name = "Microsoft IIS Connection Strings Decryption"
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"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type in ("start", "process_started") 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/"