[metadata]
creation_date = "2025/07/24"
integration = ["endpoint", "windows", "sentinel_one_cloud_funnel", "m365_defender", "crowdstrike"]
maturity = "production"
updated_date = "2025/07/24"

[rule]
author = ["Elastic"]
description = """
Identifies the creation of ASPX files in specific directories that are commonly targeted by attackers to deploy web shells.
"""
from = "now-9m"
index = [
    "winlogbeat-*",
    "logs-endpoint.events.file-*",
    "logs-windows.sysmon_operational-*",
    "endgame-*",
    "logs-sentinel_one_cloud_funnel.*",
    "logs-m365_defender.event-*",
    "logs-crowdstrike.fdr*",
]
language = "eql"
license = "Elastic License v2"
name = "Potential Web Shell ASPX File Creation"
references = [
    "https://blog.viettelcybersecurity.com/toolshell-a-critical-sharepoint-vulnerability-chain-under-active-exploitation/",
    "https://www.sentinelone.com/blog/sharepoint-toolshell-zero-day-exploited-in-the-wild-targets-enterprise-servers/",
    "https://www.rapid7.com/blog/post/2024/10/30/investigating-a-sharepoint-compromise-ir-tales-from-the-field/",
]
risk_score = 21
rule_id = "32144184-7bfa-4541-9c3f-b65f16d24df9"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Persistence",
    "Data Source: Elastic Endgame",
    "Data Source: Elastic Defend",
    "Data Source: Sysmon",
    "Data Source: SentinelOne",
    "Data Source: Microsoft Defender for Endpoint",
    "Data Source: Crowdstrike",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
file where host.os.type == "windows" and event.type != "deletion" and
  file.extension : "aspx" and
  file.path : "?:\\Program Files\\Common Files\\Microsoft Shared\\Web Server Extensions\\*" and
  not process.executable: "?:\\Windows\\System32\\msiexec.exe"
'''

[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1505"
name = "Server Software Component"
reference = "https://attack.mitre.org/techniques/T1505/"
[[rule.threat.technique.subtechnique]]
id = "T1505.003"
name = "Web Shell"
reference = "https://attack.mitre.org/techniques/T1505/003/"



[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"