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Cloudflare Firewall Events

Overview

Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable. In this documentation, you will learn how to collect and send Cloudflare Firewall events to Sekoia.io.

  • Vendor: Cloudflare
  • Supported environment: SaaS
  • Detection based on: Telemetry
  • Supported application or feature: Web application firewall logs

Configuration

Create the intake on Sekoia.io

Go to the intake page and create a new intake from the format Cloudflare.

Configure events forwarding on Cloudflare

Retrieve necessary information

First, you will have to retrieve configuration information. Connect to Cloudflare Console to collect the following :

  1. Cloudflare API Token

    • Go to My Profile, then on the left panel, click on API Tokens.
    • Click on the Create Token button and select the Create Custom Token entry.
    • Give a name to your token and set the following permissions:
    Scope Group Level
    Account Account Analytics Read
    Account Logs Read
    Account Logs Edit
    Zone Logs Read
    Zone Logs Edit
    • If you want zerotrust logs you should also add:
    Scope Group Level
    Account Zero Trust Read

    see the Cloudflare documentation

  2. Cloudflare Zone ID :

    • This information is specific to a Website.
    • On the left panel, click on Websites and select the Website you want.
    • On the right panel, there is an API section where you can retrieve the Zone ID.

Create a Logpush job

Configure a Logpush job with the following destination:

https://intake.sekoia.io/plain/batch?header_X-SEKOIAIO-INTAKE-KEY=<YOUR_INTAKE_KEY>

To do so, you can manage Logpush with cURL:

$ curl -X POST https://api.cloudflare.com/client/v4/zones/<CLOUDFLARE_ZONE_ID>/logpush/jobs \
-H "Authorization: Bearer <CLOUDFLARE_API_TOKEN>" \
-H "Content-Type: application/json" \
--data '{
    "dataset": "firewall_events",
    "enabled": true,
    "max_upload_bytes": 5000000,
    "max_upload_records": 1000,
    "logpull_options":"fields=Action,ClientASN,ClientASNDescription,ClientCountry,ClientIP,ClientIPClass,ClientRefererHost,ClientRefererPath,ClientRefererQuery,ClientRefererScheme,ClientRequestHost,ClientRequestMethod,ClientRequestPath,ClientRequestProtocol,ClientRequestQuery,ClientRequestScheme,ClientRequestUserAgent,Datetime,EdgeColoCode,EdgeResponseStatus,Kind,MatchIndex,Metadata,OriginResponseStatus,OriginatorRayID,RayID,RuleID,Source&timestamps=unix",
    "destination_conf": "https://intake.sekoia.io/plain/batch?header_X-SEKOIAIO-INTAKE-KEY=<YOUR_INTAKE_KEY>"
}' # (1)
  1. will return 
    {
  "errors": [],
  "messages": [],
  "result": {
    "id": 147,
    "dataset": "firewall_events",
    "enabled": false,
    "name": "<DOMAIN_NAME>",
    "logpull_options": "fields=<LIST_OF_FIELDS>&timestamps=rfc3339",
    "destination_conf": "https://intake.sekoia.io/plain/batch?header_X-SEKOIAIO-INTAKE-KEY=<YOUR_INTAKE_KEY>",
    "last_complete": null,
    "last_error": null,
    "error_message": null
  },
  "success": true
}

Important

Replace :

  • <YOUR_INTAKE_KEY> with the Intake key you generated in the Create the intake on Sekoia.io step.
  • <CLOUDFLARE_API_TOKEN> with the API Token you generated
  • <CLOUDFLARE_ZONE_ID> with the Zone ID you grabbed
Useful Cloudflare API endpoints

On their documentation, Cloudflare provides a list API endpoints you can use. Find below some useful endpoints:

  • https://api.cloudflare.com/client/v4/zones/<ZONE_ID>/logpush/jobs/<JOB_ID> to verify the job you previously created is correct (you need to specify the JOB_ID)
  • https://api.cloudflare.com/client/v4/zones/<ZONE_ID>/logpush/datasets/<DATASET>/jobs to get all the jobs for a specific dataset (dns_log, firewalls_events or http_requests in our case)
  • https://api.cloudflare.com/client/v4/zones/<ZONE_ID>/logpush/jobs/<JOB_ID> to update a job if you noticed a mistake after the creation of the job (wrong fields, wrong SEKOIA API Key...)

Raw Events Samples

In this section, you will find examples of raw logs as generated natively by the source. These examples are provided to help integrators understand the data format before ingestion into Sekoia.io. It is crucial for setting up the correct parsing stages and ensuring that all relevant information is captured.

{
    "Action": "block",
    "ClientIP": "113.206.179.28",
    "ClientRequestHost": "foo-bar-baz.xyz",
    "ClientRequestMethod": "GET",
    "ClientRequestPath": "/static/favicon.ico",
    "ClientRequestQuery": "",
    "Datetime": 1657630626219000000,
    "EdgeResponseStatus": 403,
    "RayID": "7299f155dda47d6b"
}

{
    "Action": "block",
    "ClientASN": 4562,
    "ClientASNDescription": "PERFORMIVE",
    "ClientCountry": "us",
    "ClientIP": "10.6.12.26",
    "ClientIPClass": "noRecord",
    "ClientRefererHost": "",
    "ClientRefererPath": "",
    "ClientRefererQuery": "",
    "ClientRefererScheme": "",
    "ClientRequestHost": "foo-bar-baz.xyz",
    "ClientRequestMethod": "GET",
    "ClientRequestPath": "/.env",
    "ClientRequestProtocol": "HTTP/1.1",
    "ClientRequestQuery": "",
    "ClientRequestScheme": "http",
    "ClientRequestUserAgent": "Mozilla/5.0 (Linux; U; Android 4.4.2; en-US; HM NOTE 1W Build/KOT49H) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 UCBrowser/11.0.5.850 U3/0.8.0 Mobile Safari/534.30",
    "Datetime": 1669858111716000000,
    "EdgeColoCode": "EWR",
    "EdgeResponseStatus": 403,
    "Kind": "firewall",
    "MatchIndex": 0,
    "Metadata": {
        "group": "cloudflare_specials",
        "rule_message": "Version Control - Information Disclosure"
    },
    "OriginResponseStatus": 0,
    "OriginatorRayID": "00",
    "RayID": "77280bee38a6c461",
    "RuleID": "100016",
    "Source": "waf"
}

Detection section

The following section provides information for those who wish to learn more about the detection capabilities enabled by collecting this intake. It includes details about the built-in rule catalog, event categories, and ECS fields extracted from raw events. This is essential for users aiming to create custom detection rules, perform hunting activities, or pivot in the events page.

The following Sekoia.io built-in rules match the intake Cloudflare WAF events. This documentation is updated automatically and is based solely on the fields used by the intake which are checked against our rules. This means that some rules will be listed but might not be relevant with the intake.

SEKOIA.IO x Cloudflare WAF events on ATT&CK Navigator

Bazar Loader DGA (Domain Generation Algorithm)

Detects Bazar Loader domains based on the Bazar Loader DGA

  • Effort: elementary
Burp Suite Tool Detected

Burp Suite is a cybersecurity tool. When used as a proxy service, its purpose is to intercept packets and modify them to send them to the server. Burp Collaborator is a network service that Burp Suite uses to help discover many kinds of vulnerabilities (vulnerabilities scanner).

  • Effort: intermediate
Correlation Potential DNS Tunnel

Detects domain name which is longer than 95 characters. Long domain names are distinctive of DNS tunnels.

  • Effort: advanced
Covenant Default HTTP Beaconing

Detects potential Covenant communications through the user-agent and specific urls

  • Effort: intermediate
Cryptomining

Detection of domain names potentially related to cryptomining activities.

  • Effort: master
Discord Suspicious Download

Discord is a messaging application. It allows users to create their own communities to share messages and attachments. Those attachments have little to no overview and can be downloaded by almost anyone, which has been abused by attackers to host malicious payloads.

  • Effort: intermediate
Dynamic DNS Contacted

Detect communication with dynamic dns domain. This kind of domain is often used by attackers. This rule can trigger false positive in non-controlled environment because dynamic dns is not always malicious.

  • Effort: master
EvilProxy Phishing Domain

Detects subdomains potentially generated by the EvilProxy adversary-in-the-middle phishing platform. Inspect the other subdomains of the domain to identify the landing page, and determine if the user submitted credentials. This rule has a small percentage of false positives on legitimate domains.

  • Effort: intermediate
Exfiltration Domain

Detects traffic toward a domain flagged as a possible exfiltration vector.

  • Effort: master
Koadic MSHTML Command

Detects Koadic payload using MSHTML module

  • Effort: intermediate
Nimbo-C2 User Agent

Nimbo-C2 Uses an unusual User-Agent format in its implants.

  • Effort: intermediate
Potential Azure AD Phishing Page (Adversary-in-the-Middle)

Detects an HTTP request to an URL typical of the Azure AD authentication flow, but towards a domain that is not one the legitimate Microsoft domains used for Azure AD authentication.

  • Effort: intermediate
Potential Bazar Loader User-Agents

Detects potential Bazar loader communications through the user-agent

  • Effort: elementary
Potential DNS Tunnel

Detects domain name which is longer than 95 characters. Long domain names are distinctive of DNS tunnels.

  • Effort: advanced
Potential Lemon Duck User-Agent

Detects LemonDuck user agent. The format used two sets of alphabetical characters separated by dashes, for example "User-Agent: Lemon-Duck-[A-Z]-[A-Z]".

  • Effort: elementary
Potential LokiBot User-Agent

Detects potential LokiBot communications through the user-agent

  • Effort: intermediate
Remote Access Tool Domain

Detects traffic toward a domain flagged as a Remote Administration Tool (RAT).

  • Effort: master
Remote Monitoring and Management Software - AnyDesk

Detect artifacts related to the installation or execution of the Remote Monitoring and Management tool AnyDesk.

  • Effort: master
Remote Monitoring and Management Software - Atera

Detect artifacts related to the installation or execution of the Remote Monitoring and Management tool Atera.

  • Effort: master
SEKOIA.IO Intelligence Feed

Detect threats based on indicators of compromise (IOCs) collected by SEKOIA's Threat and Detection Research team.

  • Effort: elementary
Sekoia.io EICAR Detection

Detects observables in Sekoia.io CTI tagged as EICAR, which are fake samples meant to test detection.

  • Effort: master
Suspicious TOR Gateway

Detects suspicious TOR gateways. Gateways are often used by the victim to pay and decrypt the encrypted files without installing TOR. Tor intercepts the network traffic from one or more apps on user’s computer, usually the user web browser, and shuffles it through a number of randomly-chosen computers before passing it on to its destination. This disguises user location, and makes it harder for servers to pick him/her out on repeat visits, or to tie together separate visits to different sites, this making tracking and surveillance more difficult. Before a network packet starts its journey, user’s computer chooses a random list of relays and repeatedly encrypts the data in multiple layers, like an onion. Each relay knows only enough to strip off the outermost layer of encryption, before passing what’s left on to the next relay in the list.

  • Effort: advanced
TOR Usage Generic Rule

Detects TOR usage globally, whether the IP is a destination or source. TOR is short for The Onion Router, and it gets its name from how it works. TOR intercepts the network traffic from one or more apps on user’s computer, usually the user web browser, and shuffles it through a number of randomly-chosen computers before passing it on to its destination. This disguises user location, and makes it harder for servers to pick him/her out on repeat visits, or to tie together separate visits to different sites, this making tracking and surveillance more difficult. Before a network packet starts its journey, user’s computer chooses a random list of relays and repeatedly encrypts the data in multiple layers, like an onion. Each relay knows only enough to strip off the outermost layer of encryption, before passing what’s left on to the next relay in the list.

  • Effort: master
Telegram Bot API Request

Detects suspicious DNS queries to api.telegram.org used by Telegram Bots of any kind

  • Effort: advanced
WAF Block Rule

Detects when one of WAF rule blocked an HTTP request

  • Effort: master
WAF Correlation Block actions

Detection of multiple block actions (more than 30) triggered by the same source by WAF detection rules

  • Effort: master

Event Categories

The following table lists the data source offered by this integration.

Data Source Description
Web application firewall logs Cloudflare protect web application with its web application firewall

In details, the following table denotes the type of events produced by this integration.

Name Values
Kind ``
Category network
Type ``

Transformed Events Samples after Ingestion

This section demonstrates how the raw logs will be transformed by our parsers. It shows the extracted fields that will be available for use in the built-in detection rules and hunting activities in the events page. Understanding these transformations is essential for analysts to create effective detection mechanisms with custom detection rules and to leverage the full potential of the collected data.

{
    "message": "{\"Action\":\"block\",\"ClientIP\":\"113.206.179.28\",\"ClientRequestHost\":\"foo-bar-baz.xyz\",\"ClientRequestMethod\":\"GET\",\"ClientRequestPath\":\"/static/favicon.ico\",\"ClientRequestQuery\":\"\",\"Datetime\":1657630626219000000,\"EdgeResponseStatus\":403,\"RayID\":\"7299f155dda47d6b\"}",
    "event": {
        "action": "block",
        "category": [
            "network"
        ],
        "dataset": "firewall-events",
        "type": [
            "denied"
        ]
    },
    "@timestamp": "2022-07-12T12:57:06.219000Z",
    "cloudflare": {
        "EdgeResponseStatus": 403,
        "RayID": "7299f155dda47d6b"
    },
    "destination": {
        "address": "foo-bar-baz.xyz",
        "domain": "foo-bar-baz.xyz",
        "registered_domain": "foo-bar-baz.xyz",
        "top_level_domain": "xyz"
    },
    "http": {
        "request": {
            "method": "GET"
        },
        "response": {
            "status_code": 403
        }
    },
    "observer": {
        "type": "firewall",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foo-bar-baz.xyz"
        ],
        "ip": [
            "113.206.179.28"
        ]
    },
    "source": {
        "address": "113.206.179.28",
        "ip": "113.206.179.28"
    },
    "url": {
        "domain": "foo-bar-baz.xyz",
        "path": "/static/favicon.ico",
        "registered_domain": "foo-bar-baz.xyz",
        "top_level_domain": "xyz"
    }
}

{
    "message": "{\"Action\":\"block\",\"ClientASN\":4562,\"ClientASNDescription\":\"PERFORMIVE\",\"ClientCountry\":\"us\",\"ClientIP\":\"10.6.12.26\",\"ClientIPClass\":\"noRecord\",\"ClientRefererHost\":\"\",\"ClientRefererPath\":\"\",\"ClientRefererQuery\":\"\",\"ClientRefererScheme\":\"\",\"ClientRequestHost\":\"foo-bar-baz.xyz\",\"ClientRequestMethod\":\"GET\",\"ClientRequestPath\":\"/.env\",\"ClientRequestProtocol\":\"HTTP/1.1\",\"ClientRequestQuery\":\"\",\"ClientRequestScheme\":\"http\",\"ClientRequestUserAgent\":\"Mozilla/5.0 (Linux; U; Android 4.4.2; en-US; HM NOTE 1W Build/KOT49H) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 UCBrowser/11.0.5.850 U3/0.8.0 Mobile Safari/534.30\",\"Datetime\":1669858111716000000,\"EdgeColoCode\":\"EWR\",\"EdgeResponseStatus\":403,\"Kind\":\"firewall\",\"MatchIndex\":0,\"Metadata\":{\"group\":\"cloudflare_specials\",\"rule_message\":\"Version Control - Information Disclosure\"},\"OriginResponseStatus\":0,\"OriginatorRayID\":\"00\",\"RayID\":\"77280bee38a6c461\",\"RuleID\":\"100016\",\"Source\":\"waf\"}",
    "event": {
        "action": "block",
        "category": [
            "network"
        ],
        "dataset": "firewall-events",
        "module": "cloudflare.waf",
        "type": [
            "denied"
        ]
    },
    "@timestamp": "2022-12-01T01:28:31.716000Z",
    "cloudflare": {
        "ClientIPClass": "noRecord",
        "EdgeColoCode": "EWR",
        "EdgeResponseStatus": 403,
        "Kind": "firewall",
        "OriginResponseStatus": 0,
        "OriginatorRayID": "00",
        "RayID": "77280bee38a6c461",
        "source": "waf"
    },
    "destination": {
        "address": "foo-bar-baz.xyz",
        "domain": "foo-bar-baz.xyz",
        "registered_domain": "foo-bar-baz.xyz",
        "top_level_domain": "xyz"
    },
    "http": {
        "request": {
            "method": "GET"
        },
        "response": {
            "status_code": 403
        },
        "version": "HTTP/1.1"
    },
    "network": {
        "protocol": "HTTP/1.1"
    },
    "observer": {
        "type": "firewall",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foo-bar-baz.xyz"
        ],
        "ip": [
            "10.6.12.26"
        ]
    },
    "source": {
        "address": "10.6.12.26",
        "geo": {
            "country_name": "us"
        },
        "ip": "10.6.12.26"
    },
    "url": {
        "domain": "foo-bar-baz.xyz",
        "path": "/.env",
        "registered_domain": "foo-bar-baz.xyz",
        "scheme": "http",
        "top_level_domain": "xyz"
    },
    "user_agent": {
        "device": {
            "name": "XiaoMi HM NOTE 1W"
        },
        "name": "UC Browser",
        "original": "Mozilla/5.0 (Linux; U; Android 4.4.2; en-US; HM NOTE 1W Build/KOT49H) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 UCBrowser/11.0.5.850 U3/0.8.0 Mobile Safari/534.30",
        "os": {
            "name": "Android",
            "version": "4.4.2"
        },
        "version": "11.0.5"
    }
}

Extracted Fields

The following table lists the fields that are extracted, normalized under the ECS format, analyzed and indexed by the parser. It should be noted that infered fields are not listed.

Name Type Description
@timestamp date Date/time when the event originated.
cloudflare.ClientIPClass string The classification of the visitor’s IP address, possible values are: unknown
cloudflare.ClientRefererHost string The referer host
cloudflare.ClientRefererPath string The referer path requested by visitor
cloudflare.ClientRefererQuery string The referer query-string was requested by the visitor
cloudflare.ClientRefererScheme string The referer URL scheme requested by the visitor
cloudflare.EdgeColoCode string IATA airport code of data center that received the request
cloudflare.EdgeResponseStatus number HTTP status code returned by Cloudflare to the client
cloudflare.Kind string The dataset of the event
cloudflare.OriginResponseStatus number status returned by the origin server
cloudflare.OriginatorRayID string The RayID of the request that issued the challenge/jschallenge
cloudflare.RayID string ID of the request
cloudflare.clientASNDescription keyword The ASN of the visitor as string
cloudflare.matchIndex number Rules match index in the chain
cloudflare.metadata object Additional product-specific information. Metadata is organized in key:value pairs. Key and Value formats can vary by Cloudflare security product and can change over time
cloudflare.source keyword The Cloudflare security product triggered by this request
destination.domain keyword The domain name of the destination.
event.action keyword The action captured by the event.
event.category keyword Event category. The second categorization field in the hierarchy.
event.dataset keyword Name of the dataset.
event.module keyword Name of the module this data is coming from.
http.request.bytes long Total size in bytes of the request (body and headers).
http.request.method keyword HTTP request method.
http.request.referrer keyword Referrer for this HTTP request.
http.response.status_code long HTTP response status code.
http.version keyword HTTP version.
network.protocol keyword Application protocol name.
observer.type keyword The type of the observer the data is coming from.
observer.vendor keyword Vendor name of the observer.
rule.description keyword Rule description
rule.id keyword Rule ID
rule.reference keyword Rule reference URL
rule.ruleset keyword Rule ruleset
source.as.number long Unique number allocated to the autonomous system.
source.geo.country_name keyword Country name.
source.ip ip IP address of the source.
source.port long Port of the source.
tls.cipher keyword String indicating the cipher used during the current connection.
tls.version_protocol keyword Normalized lowercase protocol name parsed from original string.
url.domain keyword Domain of the url.
url.path wildcard Path of the request, such as "/search".
url.query keyword Query string of the request.
url.scheme keyword Scheme of the url.
user_agent.original keyword Unparsed user_agent string.

For more information on the Intake Format, please find the code of the Parser, Smart Descriptions, and Supported Events here.