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.

Benefit from SEKOIA.IO built-in rules and upgrade Cloudflare WAF events with the following detection capabilities out-of-the-box.

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

CloudFlare Firewall Block Rule

Detects when one of CloudFlare Firewall rule (previously WAF's custom rule or managed rule) blocked an HTTP request

Effort: master

Covenant Default HTTP Beaconing

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

Effort: intermediate

Potential Bazar Loader User-Agents

Detects potential Bazar loader communications through the user-agent

Effort: elementary

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

SEKOIA.IO Intelligence Feed

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

Effort: elementary

Telegram Bot API Request

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

Effort: advanced

TrevorC2 HTTP Communication

Detects TrevorC2 HTTP communication based on the HTTP request URI and the user-agent.

Effort: elementary

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	`event`
Category	`network`
Type	``

Event Samples

Find below few samples of events and how they are normalized by SEKOIA.IO.

403.json

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

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.kind`	`keyword`	The kind of the event. The highest categorization field in the hierarchy.
`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.id`	`keyword`	Rule ID
`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.

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 :

Cloudflare Email Address
- This is your Email Address that you can find in My Profile.
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 Read analytics and logs template.
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.

Configure Logpush

Retrieve all available fields with your subscription

Depending on your subscription, you first need to get all the fields that you can forward to SEKOIA.IO by using the Cloudflare API Retrieve all available fields for a dataset.

With cURL you can use this command:

curl -s -H "X-Auth-Email: <Cloudflare Email Address>" \
-H "X-Auth-Key: <Cloudflare API Token>" \
"https://api.cloudflare.com/client/v4/zones/<Cloudflare Zone ID>/logpush/datasets/firewall_events/fields" \
| jq '.result' # (1)

will return

{
  "Action": "string; the code of the first-class action the Cloudflare Firewall took on this request. Possible actions are unknown | allow | block | challenge | jschallenge | log | connectionclose | challengesolved | challengefailed | challengebypassed | jschallengesolved | jschallengefailed | jschallengebypassed | bypass | managedchallenge | managedchallengeskipped | managedchallengenoninteractivesolved | managedchallengeinteractivesolved | managedchallengebypassed",
  "ClientASN": "int; the ASN number of the visitor",
  "ClientASNDescription": "string; the ASN of the visitor as string",
  "ClientCountry": "string; country from which request originated",
  "ClientIP": "string; the visitor's IP address (IPv4 or IPv6)",
  "ClientIPClass": "string; the classification of the visitor's IP address, possible values are: unknown | badHost | searchEngine | allowlist | monitoringService | noRecord | scan | tor",
  "ClientRefererHost": "string; the referer host",
  "ClientRefererPath": "string; the referer path requested by visitor",
  "ClientRefererQuery": "string; the referer query-string was requested by the visitor",
  "ClientRefererScheme": "string; the referer URL scheme requested by the visitor",
  "ClientRequestHost": "string; the HTTP hostname requested by the visitor",
  "ClientRequestMethod": "string; the HTTP method used by the visitor",
  "ClientRequestPath": "string; the path requested by visitor",
  "ClientRequestProtocol": "string; the version of HTTP protocol requested by the visitor",
  "ClientRequestQuery": "string; the query-string was requested by the visitor",
  "ClientRequestScheme": "string; the URL scheme requested by the visitor",
  "ClientRequestUserAgent": "string; visitor's user-agent string",
  "Datetime": "int or string; the date and time the event occurred at the edge",
  "EdgeColoCode": "string; the airport code of the Cloudflare datacenter that served this request",
  "EdgeResponseStatus": "int; HTTP response status code returned to browser",
  "Kind": "string; the kind of event, currently only possible values are: firewall",
  "MatchIndex": "int; rules match index in the chain",
  "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",
  "OriginResponseStatus": "int; HTTP origin response status code returned to browser",
  "OriginatorRayID": "string; the RayID of the request that issued the challenge/jschallenge",
  "RayID": "string; the RayID of the request",
  "RuleID": "string; the Cloudflare security product-specific RuleID triggered by this request",
  "Source": "string; the Cloudflare security product triggered by this request. Possible sources are unknown | asn | country | ip | iprange | securitylevel | zonelockdown | waf | firewallrules | uablock | ratelimit | bic | hot | l7ddos | validation | botfight | apishield | botmanagement | dlp | firewallmanaged | firewallcustom"
}

Save the fields you want to send to SEKOIA.IO. It will be used to configure the Logpush job. It this example :

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

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 "x-auth-email: <Cloudflare Email Address>" \
-H "X-Auth-Key: <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=<LIST_OF_FIELDS>&timestamps=rfc3339",
    "destination_conf": "https://intake.sekoia.io/plain/batch?header_X-SEKOIAIO-INTAKE-KEY=<YOUR_INTAKE_KEY>"
}' # (1)