Cloudflare DNS logs

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 DNS logs to Sekoia.io.

Vendor: Cloudflare
Supported environment: SaaS
Detection based on: Telemetry
Supported application or feature: DNS records

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 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
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": "dns_logs",
    "enabled": true,
    "max_upload_bytes": 5000000,
    "max_upload_records": 1000,
    "logpull_options":"fields=ColoCode,EDNSSubnet,EDNSSubnetLength,QueryName,QueryType,ResponseCached,ResponseCode,SourceIP,Timestamp&timestamps=unix",
    "destination_conf": "https://intake.sekoia.io/plain/batch?header_X-SEKOIAIO-INTAKE-KEY=<YOUR_INTAKE_KEY>"
}' # (1)

will return

{
  "errors": [],
  "messages": [],
  "result": {
    "id": 148,
    "dataset": "dns_log",
    "enabled": false,
    "name": "<DOMAIN_NAME>",
    "logpull_options": "fields=<LIST_OF_FIELDS>=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.

dns_type_1dns_type_2dns_type_28dns_type_65535

{
    "QueryName": "foO-BAR-baz.xYz.",
    "QueryType": 1,
    "ResponseCode": 0,
    "Timestamp": 1657233726004000000
}

{
    "QueryName": "foO-BAR-baz.xYz.",
    "QueryType": 2,
    "ResponseCode": 0,
    "Timestamp": 1657233726004000000
}

{
    "QueryName": "foO-BAR-baz.xYz.",
    "QueryType": 28,
    "ResponseCode": 0,
    "Timestamp": 1657233726004000000
}

{
    "QueryName": "foO-BAR-baz.xYz.",
    "QueryType": 65353,
    "ResponseCode": 0,
    "Timestamp": 1657233726004000000
}

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 DNS logs. 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 DNS logs on ATT&CK Navigator

Bazar Loader DGA (Domain Generation Algorithm)

Detects Bazar Loader domains based on the Bazar Loader DGA

Effort: elementary

Correlation Potential DNS Tunnel

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

Effort: advanced

Cryptomining

Detection of domain names potentially related to cryptomining activities.

Effort: master

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

Potential DNS Tunnel

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

Effort: advanced

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

Sliver DNS Beaconing

Detects suspicious DNS queries known from Sliver beaconing

Effort: intermediate

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

Event Categories

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

Data Source	Description
`DNS records`	Cloudflare DNS logs provides detailed logs on handled DNS queries

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

Name	Values
Kind	``
Category	`network`
Type	`info`

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.

dns_type_1.jsondns_type_2.jsondns_type_28.jsondns_type_65535.json

{
    "message": "{\"QueryName\":\"foO-BAR-baz.xYz.\",\"QueryType\":1,\"ResponseCode\":0,\"Timestamp\":1657233726004000000}\n",
    "event": {
        "category": [
            "network"
        ],
        "dataset": "dns_logs",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2022-07-07T22:42:06.004000Z",
    "dns": {
        "question": {
            "name": "foO-BAR-baz.xYz",
            "registered_domain": "foO-BAR-baz.xYz",
            "top_level_domain": "xYz",
            "type": "A"
        },
        "response_code": "NoError"
    },
    "observer": {
        "type": "dns",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foO-BAR-baz.xYz"
        ]
    }
}

{
    "message": "{\"QueryName\":\"foO-BAR-baz.xYz.\",\"QueryType\":2,\"ResponseCode\":0,\"Timestamp\":1657233726004000000}\n",
    "event": {
        "category": [
            "network"
        ],
        "dataset": "dns_logs",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2022-07-07T22:42:06.004000Z",
    "dns": {
        "question": {
            "name": "foO-BAR-baz.xYz",
            "registered_domain": "foO-BAR-baz.xYz",
            "top_level_domain": "xYz",
            "type": "NS"
        },
        "response_code": "NoError"
    },
    "observer": {
        "type": "dns",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foO-BAR-baz.xYz"
        ]
    }
}

{
    "message": "{\"QueryName\":\"foO-BAR-baz.xYz.\",\"QueryType\":28,\"ResponseCode\":0,\"Timestamp\":1657233726004000000}\n",
    "event": {
        "category": [
            "network"
        ],
        "dataset": "dns_logs",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2022-07-07T22:42:06.004000Z",
    "dns": {
        "question": {
            "name": "foO-BAR-baz.xYz",
            "registered_domain": "foO-BAR-baz.xYz",
            "top_level_domain": "xYz",
            "type": "AAAA"
        },
        "response_code": "NoError"
    },
    "observer": {
        "type": "dns",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foO-BAR-baz.xYz"
        ]
    }
}

{
    "message": "{\"QueryName\":\"foO-BAR-baz.xYz.\",\"QueryType\":65353,\"ResponseCode\":0,\"Timestamp\":1657233726004000000}\n",
    "event": {
        "category": [
            "network"
        ],
        "dataset": "dns_logs",
        "type": [
            "info"
        ]
    },
    "@timestamp": "2022-07-07T22:42:06.004000Z",
    "dns": {
        "question": {
            "name": "foO-BAR-baz.xYz",
            "registered_domain": "foO-BAR-baz.xYz",
            "top_level_domain": "xYz"
        },
        "response_code": "NoError"
    },
    "observer": {
        "type": "dns",
        "vendor": "Cloudflare"
    },
    "related": {
        "hosts": [
            "foO-BAR-baz.xYz"
        ]
    }
}

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.ColoCode`	`keyword`	IATA airport code of data center that received the request
`cloudflare.EDNSSubnet`	`keyword`	EDNS Client Subnet (IPv4 or IPv6)
`cloudflare.EDNSSubnetLength`	`number`	EDNS Client Subnet length
`cloudflare.ResponseCached`	`bool`	Whether the response was cached or not
`dns.question.name`	`keyword`	The name being queried.
`event.category`	`keyword`	Event category. The second categorization field in the hierarchy.
`event.dataset`	`keyword`	Name of the dataset.
`event.type`	`keyword`	Event type. The third categorization field in the hierarchy.
`observer.type`	`keyword`	The type of the observer the data is coming from.
`observer.vendor`	`keyword`	Vendor name of the observer.
`source.ip`	`ip`	IP address of the source.

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

Scope	Group	Level
Account	Account Analytics	Read
Account	Logs	Read
Account	Logs	Edit
Zone	Logs	Read
Zone	Logs	Edit