BitNinja is a disruptive technology so there are some concepts that are important to understand in order to comprehend the way BitNinja works.
IP reputation is a very effective way of securing your server. It’s a database with information about various IPs in the world. BitNinja clients use IP reputation information automatically on their servers to make security decisions and to find out more about an IP address.
Every server with BitNinja can detect and defend a wide range of attacks. The server can send gathered incident information to our central database. Based on the type, timing, and amount of incidents an IP has in the database, it is categorized into one of the following lists:
If there is no information about an IP address, or based on the latest behavior the IP is not listed.
User Challenge list
In traditional IP reputation terminology, we differentiate block- and allow lists. An IP can be trusted (allow listed) or absolutely denied (block listed). This concept is very inflexible and this is the cause of the bad reputation that IP reputation lists have. If an IP is false-positively block listed, users will get angry at you because they can't access the system they want to and they will be frustrated as they are unable to do anything about it.
That's how the concept of challenge list was born. We wanted to represent a list of IPs we think may be malicious but we are not completely sure of it yet.
The challenge list contains suspicious IPs that the BitNinja client handles with special care. BitNinja has different CAPTCHA modules for different protocols. The duty of a CAPTCHA module is as follows:
- Decide if the user is human or not
- Inform the user about the fact that his/her IP has been challenge listed
- Provide a safe way for the user to delist his/her IP
- Save any requests made by non-human parties, growing the knowledgebase about the IP and the sin list.
- Honeypotting by pretending to be a vulnerable system so bots will try to connect
Traffic from an IP can be malicious and innocent at the same time. Think of an infected computer. The requests the virus will make are malicious but the requests the user makes by using his/her browser are innocent. If we completely block the traffic, the user will not know about the infection. Challenge listing solves this by informing the user of the challenge listing and helps the innocent users resolve their IPs.
If there are suspicious incidents about an IP address, the IP can be challenge listed by some users. If an IP is user-challenge listed, it means it is only challenge listed by some users, not all BitNinja users. When we have enough information about an IP that is sending malicious requests, we move it to the global challenge list. If an IP is globally challenge listed, it is challenge listed by all BitNinja servers.
You can check if an IP is listed by BitNinja using the web front end https://admin.bitninja.io or using our CLI front end that is called bitninjacli.
You can check, add, and delete IPs from the challenge list using both tools.
bitninjacli --greylist --check 18.104.22.168
To see if an IP is on any of these lists, you can use the following command:
for set in $(ipset -L -n); do echo $set; ipset test $set 22.214.171.124; done
If one of your servers catches an attack and the IP is not yet challenge listed, the IP will be user challenge listed and this information will be distributed across all of your servers instantly.
Global challenge list
If there is enough evidence that an IP is suspicious, we move it to the global challenge list and distribute this information to every BitNinja protected server.
If there are no logs about a challenge listed IP address it will be delisted:
- Static IP addresses: 3 months without logs
- Dynamic IP address: 7 days without logs
Global block lists
When an IP is globally challenge listed and is still sending malicious requests, we identify it as dangerous. Such IPs are moved to the global block list we maintain. BitNinja clients will drop packets for IPs on the global block list. The false-positive rate of the global block list is very low, as there are many steps before we decide to block list an IP. block listed IPs are moved back to the challenge list from time-to-time to check if the traffic is still malicious or the system has been disinfected.
User-level block- and allow lists
You can use BitNinja to maintain block lists and allow lists across your servers. The BitNinja Dashboard or our command-line interface, BitNinja CLI, can be used to add/remove/check IPs against a user’s block list and allow list. If you block list an IP, all of your servers will DROP any packets from that IP. You can add CIDRs to your block list or your allow list via BitNinja Dashboard. When you add an IP to the allow list it guarantees BitNinja won't interfere with that IP.
You can set an expiration date for each IP address or IP range or country after which they are removed from the account-level block list or allow list.
It is also possible to specify a server on which you whish to block list or allow list the given IP address. This way the IP address will be block listed/allow listed only on the specified server. You can also specify a server in case of the country block list or allow list.
Allow listing an IP will only bypass BitNinja iptables chains. There can be other iptables rules blocking the traffic. Allow listing is not equal to universal ACCEPT, only to bypass BitNinja.
Allow listed addresses are processed prior to block listed ones starting from BitNinja version 1.16.16.
Essential list provides protection against the most dangerous IPs. These IPs are often used by the most agressive hackers all around the world. When an IP generates more than 5000 malicious requests, BitNinja places it on this list. The essential list is part of our basic IP reputation package, so it's available for every BitNinja user.
You can add whole countries to your block list or allow list. The country blocking (or allow listing) feature of BitNinja uses publicly available zone files to add the selected countries' IP ranges to the user block list or user allow list. The zone files can be found at http://www.ipdeny.com/ipblocks.
You can add countries on the Dashboard in the Firewall > Block list > Country menu.
Here you can specify if you want to block list a country only on one server or if you want to block a country until a specific date.
If you have ipsetv6 or ipsetv4 and add a country or remove it to the block list or allow list, the ipsets will be reloaded on your server(s).
If you don't have ipset, BitNinja uses iptables rules and simulated ipset. When you add or remove a country, the iptables rules will be reloaded.
For now, if you have more than one server and add a country to your block list (or allow list), the selected IP ranges will be block listed (or allow listed) on all your servers.
Blocking an entire country might interfere with your extensions and plugins.
Searching in the BitNinja IP reputation database
You can search the IP history using the BitNinja Dashboard at https://admin.bitninja.io.
The search field is on the top of the page. You can type an IP and choose the IP option to search in the BitNinja IP reputation database.
It’s possible that BitNinja identifies internet crawlers as malicious bots due to their configuration and may challenge list them due to security reasons.
Our management decided it is the responsibility of our customers (the hosting providers) and the end-user to agree on what monitoring solutions, crawlers and bots do they allow. As it is always a risk of some level to allow an IP, let alone on a global level. We do not want to bear the responsibility of deciding what bots and crawlers we do allow. As mentioned above the decision of what bots and crawlers to allow is the hosting providers' and the end-users' therefore please contact the hosting providers and or the end-users with this request.
If that is not possible we can disable the abuse email sending from the IP addresses used by the service. To do that please contact us at firstname.lastname@example.org.
Domain allow list
Our users have the option to allow services used on the server based on the domains of the services. This way all requests from the allow listed domains will bypass BitNinja.
To do this you need to add the domain of the service under the
[filters] flag as
domain_whitelist = 'exampleservice.com' in the Shogun module's config file in the
Restart BitNinja so the changes will take effect.
Allow listing a domain also allows the subdomains. e.g.:
crawler-01.exampleservice.com is also allowed if
exampleservice.com is allow listed.
Allow listing domains does not cause any performance issues, as the Domain-based allow listing feature was present in the agent a long time ago. The only thing that changed is that the users can now add domains freely. The feature is based on reverse DNS lookup, however not all IP addresses are resolved. There are also IP services globally allow listed via IP address ranges as well. There is also a cache in place to further reduce any effect on the performance of the BitNinja agent.
There are domains allow listed by default like Google crawlers, Yandex and Bing bots etc.
You can find the complete list here.
For the time being BitNinja does not support IPv6. If you are not using IPv6 it's recommended to disable it.
If BitNinja caught an IPv4 address, the attacker can still attack through IPv6.
To disable IPv6 edit the file:
And fill in the following lines at the end of that file
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
Save the file and close it. Restart
BitNinja will support IPv6 in the future.