---
title: "Allow Network Discovery In Firewall"
excerpt: "Disable or Modify Cloud Firewall, Impair Defenses"
categories:
  - Endpoint
last_modified_at: 2021-06-23
toc: true
toc_label: ""
tags:
  - Disable or Modify Cloud Firewall
  - Defense Evasion
  - Impair Defenses
  - Defense Evasion
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  - Endpoint
---



[Try in Splunk Security Cloud](https://www.splunk.com/en_us/cyber-security.html){: .btn .btn--success}

#### Description

This search is to detect a suspicious modification to the firewall to allow network discovery on a machine. This technique was seen in couple of ransomware (revil, reddot) to discover other machine connected to the compromised host to encrypt more files.

- **Type**: [TTP](https://github.com/splunk/security_content/wiki/Detection-Analytic-Types)
- **Product**: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- **Datamodel**: [Endpoint](https://docs.splunk.com/Documentation/CIM/latest/User/Endpoint)
- **Last Updated**: 2021-06-23
- **Author**: Teoderick Contreras, Splunk
- **ID**: ccd6a38c-d40b-11eb-85a5-acde48001122


#### [ATT&CK](https://attack.mitre.org/)

| ID             | Technique        |  Tactic             |
| -------------- | ---------------- |-------------------- |
| [T1562.007](https://attack.mitre.org/techniques/T1562/007/) | Disable or Modify Cloud Firewall | Defense Evasion |

| [T1562](https://attack.mitre.org/techniques/T1562/) | Impair Defenses | Defense Evasion |

#### Search

```

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_netsh` Processes.process= "*firewall*" Processes.process= "*group=\"Network Discovery\"*"  Processes.process="*enable*" Processes.process="*Yes*" by Processes.dest Processes.user Processes.parent_process Processes.original_file_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.parent_process_name 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `allow_network_discovery_in_firewall_filter`
```

#### Macros
The SPL above uses the following Macros:
* [process_netsh](https://github.com/splunk/security_content/blob/develop/macros/process_netsh.yml)
* [security_content_ctime](https://github.com/splunk/security_content/blob/develop/macros/security_content_ctime.yml)
* [security_content_summariesonly](https://github.com/splunk/security_content/blob/develop/macros/security_content_summariesonly.yml)

Note that `allow_network_discovery_in_firewall_filter` is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

#### Required field
* _time
* Processes.dest
* Processes.user
* Processes.parent_process_name
* Processes.parent_process
* Processes.original_file_name
* Processes.process_name
* Processes.process
* Processes.process_id
* Processes.parent_process_path
* Processes.process_path
* Processes.parent_process_id


#### How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

#### Known False Positives
network admin may modify this firewall feature that may cause this rule to be triggered.

#### Associated Analytic story
* [Ransomware](/stories/ransomware)
* [Revil Ransomware](/stories/revil_ransomware)


#### Kill Chain Phase
* Exploitation




Note that risk score is calculated base on the following formula: `(Impact * Confidence)/100`



#### Reference

* [https://kb.fortinet.com/kb/documentLink.do?externalID=FD52469](https://kb.fortinet.com/kb/documentLink.do?externalID=FD52469)
* [https://app.any.run/tasks/c0f98850-af65-4352-9746-fbebadee4f05/](https://app.any.run/tasks/c0f98850-af65-4352-9746-fbebadee4f05/)



#### Test Dataset
Replay any dataset to Splunk Enterprise by using our [`replay.py`](https://github.com/splunk/attack_data#using-replaypy) tool or the [UI](https://github.com/splunk/attack_data#using-ui).
Alternatively you can replay a dataset into a [Splunk Attack Range](https://github.com/splunk/attack_range#replay-dumps-into-attack-range-splunk-server)

* [https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/ransomware_ttp/data2/windows-sysmon.log](https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/ransomware_ttp/data2/windows-sysmon.log)



[*source*](https://github.com/splunk/security_content/tree/develop/detections/endpoint/allow_network_discovery_in_firewall.yml) \| *version*: **2**