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[New Rule] Simple HTTP Web Server Creation #4308

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112 changes: 112 additions & 0 deletions rules/linux/persistence_simple_web_server_creation.toml
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[metadata]
creation_date = "2024/12/17"
integration = ["endpoint"]
maturity = "production"
updated_date = "2024/12/17"

[rule]
author = ["Elastic"]
description = """
This rule detects the creation of a simple HTTP web server using PHP or Python built-in modules. Adversaries may create
simple HTTP web servers to establish persistence on a compromised system by uploading a reverse or command shell payload
to the server web root, allowing them to regain remote access to the system if lost.
"""
from = "now-9m"
index = ["logs-endpoint.events.process*"]
language = "eql"
license = "Elastic License v2"
name = "Simple HTTP Web Server Creation"
risk_score = 21
rule_id = "907a26f5-3eb6-4338-a70e-6c375c1cde8a"
setup = """## Setup

This rule requires data coming in from Elastic Defend.

### Elastic Defend Integration Setup
Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.

#### Prerequisite Requirements:
- Fleet is required for Elastic Defend.
- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).

#### The following steps should be executed in order to add the Elastic Defend integration on a Linux System:
- Go to the Kibana home page and click "Add integrations".
- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
- Click "Add Elastic Defend".
- Configure the integration name and optionally add a description.
- Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. [Helper guide](https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html).
- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/8.10/agent-policy.html).
- Click "Save and Continue".
- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
"""
severity = "low"
tags = [
"Domain: Endpoint",
"OS: Linux",
"Use Case: Threat Detection",
"Tactic: Persistence",
"Tactic: Execution",
"Tactic: Command and Control",
"Data Source: Elastic Defend",
]
timestamp_override = "event.ingested"
type = "eql"
query = '''
process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and (
(process.name regex~ """php?[0-9]?\.?[0-9]{0,2}""" and process.args == "-S") or
(process.name like "python*" and process.args in ("--cgi", "CGIHTTPServer"))
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Thoughts on adding http.server (known as SimpleHTTPServer) as well? --> python -m http.server. You can setup CGI with the --cgi argument as well and bind to a specific port or listen on any address. I'd be interested in alerts where 0.0.0.0 is the specified address as it is a "accept any" on cloud instances.

Another option would be Flask setup via inline code execution as shown below. I thing from command line args you could check for import flask and app.run and flag it as you will always need to import and initialize call app.run.

python3 -c "from flask import Flask; app = Flask(__name__); @app.route('/') def hello(): return 'Hello, World!'; app.run(host='0.0.0.0', port=8000)"

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The python web server spawn is already in

(process.name like "python*" and process.args in ("http.server", "SimpleHTTPServer")) or
. I put this one with cgi and -S for PHP as these command flags allow you to dynamically execute code that is hosted on the server. So it can serve as a cmd/reverse shell backdoor if you spawn them like this. Just the web server is only for downloading.

I did not add flask in there because it requires an additional module, which attackers would prefer not to install. And I think starting flask applications will be very noisy. I can check telemetry though!

)
'''

[[rule.threat]]
framework = "MITRE ATT&CK"

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

[[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]]
framework = "MITRE ATT&CK"

[rule.threat.tactic]
name = "Execution"
id = "TA0002"
reference = "https://attack.mitre.org/tactics/TA0002/"

[[rule.threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"

[[rule.threat.technique.subtechnique]]
name = "Unix Shell"
id = "T1059.004"
reference = "https://attack.mitre.org/techniques/T1059/004/"

[[rule.threat]]
framework = "MITRE ATT&CK"

[rule.threat.tactic]
name = "Command and Control"
id = "TA0011"
reference = "https://attack.mitre.org/tactics/TA0011/"

[[rule.threat.technique]]
name = "Application Layer Protocol"
id = "T1071"
reference = "https://attack.mitre.org/techniques/T1071/"
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