Skip to content
Sudonix

Installing and Configuring CrowdSec in Cloudflare

Security
  • DownPWundefined

    @phenomlab brings us a lot so here is a modest contribution to thank him and for the pleasure of sharing.

    🎅 Merry Christmas to everyone 🎅

    Installing and Configuring CrowdSec in Cloudflare

    We will see how to install and configure the Cloudflare bouncer to add another layer of security on top of our Cloudflare to protect your website against cyber threats.

    Cloudflare is a CDN (a global web content delivery network) that provides various services that allow among other things to manage DNS zones, distribute web content, secure applications and infrastructure.

    Several types of subscriptions are available. Today I’m going to show what’s achievable with CloudFlare’s free plan.

    CrowdSec is a FOSS security tool that works using collaborative security as users help each other by sharing information about attacks and blocking them both locally and among all other CrowdSec users.

    CrowdSec consists of two parts: the agent which analyzes log files, detects attacks and holds also the local API (lapi) as well as the bouncer which mitigates them. We install both components in this tutorial.

    One of the services that CrowdSec is able to protect is HTTP. Together with Cloudflare, it provides an extra layer of security against attacks such as aggressive mining, scanning/probing, path traversal, access to sensitive data, DDos L7 attacks, SQL injection and more again.

    CrowdSec is able to mitigate threats directly on Cloudflare by using the API provided by Cloudflare to block traffic or force suspicious users to go through a CAPTCHA challenge using the CrowdSec Cloudflare bouncer. We will therefore see how to configure the Cloudflare bouncer.

    Prerequisites

    https://support.cloudflare.com/hc/en-us/articles/200170786-Restoring-original-visitor-IPs

    Configuring the API token in CloudFlare

    First, here we generate a token to authenticate to the CloudFlare API with the right permissions.

    – Go to My Profile/API Tokens:

    01.png

    – Then create a Custom Token:
    02.png

    – Give it the name crowdsec then select the following permissions:

    Account - Account Filter Lists - Edit
Account - Account Firewall Access - Edit
Zone - Zone - Read
Zone - Firewall Services - Edit

    03.png

    – Then validate via the Create Token button:
    04.png

    – We have a small summary with the token that is going well. Keep it preciously because impossible to find this one 😉

    25c83a0c-44b6-4afb-a317-635f99fca2cf-image.png

    – So let’s test access to the CloudFlare API to see if everything is OK on that side (Adapt with yourtokens):

    curl -X GET "https://api.cloudflare.com/client/v4/user/tokens/verify" \     
-H "Authorization: Bearer 5hhTxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx6W0jzk" \     
-H "Content-Type:application/json"

    25c83a0c-44b6-4afb-a317-635f99fca2cf-image.png

    07.png

    Installation and configuration of CrowdSec’s CloudFlare bouncer

    – We install the bouncer:

    sudo apt install crowdsec-cloudflare-bouncer

    08.png

    – We will configure the bouncer by editing its configuration file:

    sudo nano etc/crowdsec/bouncers/crowdsec-cloudflare-bouncer.yaml

    # CrowdSec Config
crowdsec_lapi_url: http://localhost:8080/
crowdsec_lapi_key: 7xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
crowdsec_update_frequency: 10s

#Cloudflare Config. 
cloudflare_config:
  accounts: 
  - id: [ID]
    token: [TOKEN]
    ip_list_prefix: crowdsec
    default_action: managed_challenge
    zones:
    - actions: 
      - managed_challenge # valid choices are either of managed_challenge, js_challenge, block
      zone_id: [ZONE_ID]
    

  update_frequency: 30s # the frequency to update the cloudflare IP list 

# Bouncer Config
daemon: true
log_mode: file
log_dir: /var/log/ 
log_level: info # valid choices are either debug, info, error 
log_max_size: 40
log_max_age: 30
log_max_backups: 3
compress_logs: true

prometheus:
  enabled: false
  listen_addr: 127.0.0.1
  listen_port: 2112

    – The things to focus on are:

    • [ID]: Account ID of your Cloudflare account

    • [TOKEN]: the token generated by CrowdSec that we kept preciously 🙂

    • [ZONE_ID]: ID of the Cloudflare zone you want to protect

    • prometheus: if we don’t care, let’s turn it off. (log analyzer and graphs)

      !! The information can be found from the “Overview” tab of the area. A more comprehensive guide here

    0588a715-c35f-4c62-888e-7a7584c47d71-image.png 297cf5c4-0eed-4a5d-9c32-9a8b9087247b-image.png

    – We save the file.

    – IMPORTANT: Next, as the bouncer documentation states, we run the following command to clean up the existing CloudFlare components created by the bouncer:

    sudo crowdsec-cloudflare-bouncer -d

    58435d5e-0692-4265-9d2f-9367694b8910-image.png

    – If you don’t do this, you may get such errors in the bouncer logs:

    time="22-12-2022 01:06:47" level=info msg="Starting crowdsec-cloudflare-bouncer v0.2.1-debian-pragmatic-6b30687c25xxxxxxxxxxxxxxxxxxx59"
time="22-12-2022 01:06:47" level=info msg="Using API key auth"
time="22-12-2022 01:06:49" level=info msg="using existing  ip list crowdsec_managed_challenge 221xxxxxxxxxxxxxxxxxxxxxxxx4" account_id=53xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
time="22-12-2022 01:06:51" level=error msg="error filter at index (0) conflicts with an existing filter (10202) in creating firewall rule (ip.src in $crowdsec_managed_challenge)" account_id=53xxxxxxxxxxxxxxxxxxxxxxx zone_id=30xxxxxxxxxxxxxxxxxxxxxxxx
time="22-12-2022 01:06:51" level=error msg="filter at index (0) conflicts with an existing filter (10202)" account_id=533xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
time="22-12-2022 01:06:51" level=error msg="filter at index (0) conflicts with an existing filter (10202)" account_id=533xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
time="22-12-2022 01:06:51" level=fatal msg="filter at index (0) conflicts with an existing filter (10202)"

    – And you will not be able to empty the list present in CloudFlare:

    b9a98a71-5083-4cc7-bea2-483ede980262-image.png

    f969908a-87f4-433b-8529-5a8c0699d916-image.png

    – Now, we restart the bouncer so that they can populate the IP address list and the WAF Firewall rule in CloudFlare:

    systemctl stop crowdsec-cloudflare-bouncer
systemctl start crowdsec-cloudflare-bouncer

    74936946-e317-482a-a484-8eb11623d2e8-image.png

    a2488981-f24d-454a-8dc7-6ca40b78a014-image.png

    Managing multiple zones

    If we want to manage multiple zones, we need to slightly modify the configuration file:

    # Cloudflare Config.
cloudflare_config:
  accounts:
  - id: [ID]
    token: [TOKEN]
    ip_list_prefix: crowdsec
    default_action: challenge
    zones:
      - zone_id: [ZONE1_ID]
        actions:
        - challenge
      - zone_id: [ZONE2_ID]
        actions:
        - challenge
      [...]

    – Assuming the zones belong to the same account.

    – If you have already started the service, you will find the cache file /var/lib/crowdsec/crowdsec-cloudflare-bouncer/cache/cloudflare-cache.json

    – I find it better to stop the service, delete the cache file and restart it, so as to force a configuration to reload.

    – Sources :

    https://www.crowdsec.net/blog/installing-and-configuring-crowdsec-into-cloudflare

    https://docs.crowdsec.net/docs/bouncers/cloudflare/

    PW and WS Spirit alive

    1
  • DownPWundefined DownPW marked this topic as a regular topic on
  • phenomlabundefined

    @DownPW thanks very much for this incredibly detailed guide. Anyone else reading this should certainly consider deploying this as part of their security platform.

    Remember - security isn’t a product, but a combination of best practice, common sense, strategy, and learning from others in the same situation. What better way to fortify your own castle with input and knowledge from a wider community?

    Knowledge is power, and so much more powerful when shared.

    Author of OGProxy, Swatch, Threaded, Card, and most of Sudonix's bugs…

    1
  • DownPWundefined

    @phenomlab

    you are incredibly right. It’s just a stone to add on all the measures to be taken.

    PW and WS Spirit alive

    1
  • phenomlabundefined

    @DownPW yeah, I seem to spend a large amount of my time trying to educate people that there’s no silver bullet when it comes to security.

    Author of OGProxy, Swatch, Threaded, Card, and most of Sudonix's bugs…

    0

Related Topics
  • phenomlabundefined

    Warning for Android users to urgently delete these apps if installed

    Security
    1
    1 Votes
    1 Posts
    232 Views
    No one has replied
  • DownPWundefined

    ProtonMail Complied with 5,957 Data Requests in 2022 – Still Secure and Private?

    Privacy
    8
    12 Votes
    8 Posts
    507 Views
    phenomlabundefined

    @crazycells good question. Gmail being provided by Google is going to be one of the more secure by default out of the box, although you have to bear in mind that you can have the best security in the world, but that is easily diluted by user decision.

    Obviously, it makes sense to secure all cloud based services with at least 2fa protection, or better still, biometric if available, but email still remains vastly unprotected (unless enforced in the sense of 2fa, which I know Sendgrid do) because of user choice (in the sense that users will always go for the path of least resistance when it comes to security to make their lives easier). The ultimate side effect of taking this route is being vulnerable to credentials theft via phishing attacks and social engineering.

    The same principle would easily apply to Proton Mail, who also (from memory) do not enforce 2fa. Based on this fact, neither product is more secure than the other without one form of additional authentication at least being imposed.

    In terms of direct attack on the servers holding mail accounts themselves, this is a far less common type of attack these days as tricking the user is so much simpler than brute forcing a server where you are very likely to be detected by perimeter security (IDS / IPS etc).

  • DownPWundefined

    Setting for high load and prevent DDoS (sysctl, iptables, crowdsec or other)

    Security
    4
    0 Votes
    4 Posts
    690 Views
    phenomlabundefined

    @DownPW 🙂 most of this really depends on your desired security model. In all cases with firewalls, less is always more, although it’s never as clear cut as that, and there are always bespoke ports you’ll need to open periodically.

    Heztner’s DDoS protection is superior, and I know they have invested a lot of time, effort, and money into making it extremely effective. However, if you consider that the largest ever DDoS attack hit Cloudflare at 71m rps (and they were able to deflect it), and each attack can last anywhere between 8-24 hours which really depends on how determined the attacker(s) is/are, you can never be fully prepared - nor can you trace it’s true origin.

    DDoS attacks by their nature (Distributed Denial of Service) are conducted by large numbers of devices whom have become part of a “bot army” - and in most cases, the owners of these devices are blissfully unaware that they have been attacked and are under command and control from a nefarious resource. Given that the attacks originate from multiple sources, this allows the real attacker to observe from a distance whilst concealing their own identity and origin in the process.

    If you consider the desired effect of DDoS, it is not an attempt to access ports that are typically closed, but to flood (and eventually overwhelm) the target (such as a website) with millions of requests per second in an attempt to force it offline. Victims of DDoS attacks are often financial services for example, with either extortion or financial gain being the primary objective - in other words, pay for the originator to stop the attack.

    It’s even possible to get DDoS as a service these days - with a credit card, a few clicks of a mouse and a target IP, you can have your own proxy campaign running in minutes which typically involves “booters” or “stressers” - see below for more

    https://heimdalsecurity.com/blog/ddos-as-a-service-attacks-what-are-they-and-how-do-they-work

    @DownPW said in Setting for high load and prevent DDoS (sysctl, iptables, crowdsec or other):

    in short if you have any advice to give to secure the best.

    It’s not just about DDos or firewalls. There are a number of vulnerabilities on all systems that if not patched, will expose that same system to exploit. One of my favourite online testers which does a lot more than most basic ones is below

    https://www.immuniweb.com/websec/

    I’d start with the findings reported here and use that to branch outwards.

  • phenomlabundefined

    Facebook fined for forcing users to agree to personalised ads

    Privacy
    30
    19 Votes
    30 Posts
    628 Views
    JACundefined

    @phenomlab 100%.

  • DownPWundefined

    Crowdsec: a replacement for Fail2ban

    Security
    3
    4 Votes
    3 Posts
    1k Views
    DownPWundefined

    @phenomlab

    No they have a free and pro console instance.
    We can see alert with IP, Source AS, scenario attack etc…

    Installation on the NODEBB server without problems. Very good tools

    cf7e5a89-84f4-435b-82eb-434c0bfc895e-image.png
    cc82a10e-a1f1-4fd8-a433-7c9b2d31f254-image.png

    1b7147b0-37c6-4d87-b4f1-a0fe92e74afd-image.png

    7c21fc10-1825-48e1-a993-92b84455f074-image.png

    –
    We can also do research on IPs via the crowdsec analyzer

    I believe it’s 500 per month in the Free version

    43bc8265-a57c-4439-829c-0bb8602d99b4-image.png

  • phenomlabundefined

    Securing your webserver against common attacks

    Blog
    1
    1 Votes
    1 Posts
    249 Views
    No one has replied
  • phenomlabundefined

    Addressing vulnerability management

    Blog
    1
    0 Votes
    1 Posts
    250 Views
    No one has replied
  • phenomlabundefined

    Never underestimate the importance of security

    Blog
    1
    0 Votes
    1 Posts
    229 Views
    No one has replied