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DDOS Attacks / AI botfarm overload
Posted: Wed May 07, 2025 5:13 pm
by johu
Starting yesterday we saw massive bulks of requests that overloaded our server. I blocked the most active subnets but it is near impossible to catch all.
I'm not sure who is behind this and what their intention is.
A frequently queried item is the memberlist which I now bluntly disabled. This takes some load off the database. I also pruned all users that never posted anything and were last active before 2025.
I will keep this topic updated.
UPDATE: openinverter.org is now protected by anubis. If you have trouble logging in, go to
https://openinverter.org:8444/forum and log in there once. Thereafter the normal site should work as well
Re: DDOS - Entire Country of Vietnam banned
Posted: Wed May 07, 2025 11:54 pm
by Proton
That is weird. Hopefully they cannot VPN into another country and do it from there. Maybe some kids.
Re: DDOS - Entire Country of Vietnam banned
Posted: Thu May 15, 2025 8:00 am
by johu
Today it somewhat picked up again, this time from Brazil. I have removed the Vietnam ban and banned some hand-asorted subnets.
BTW you can see something is wrong when there are more than, say, 200 active users
Re: DDOS - Entire Country of Vietnam banned
Posted: Thu May 15, 2025 3:21 pm
by Proton
If that server is at home you can install a PFsense firewall - Free software and then you can have lists added to known bad servers or IPs.
You just need a computer with 2 NIC cards
these are some of my lists.
you can also have VPN tunnels from you phones or PC to send all traffic back home through your firewall. All phones in my family send all traffic back home tunneled . that way you can connect to any wifi hotspts and nobody can see your traffic.
I installed the pFsense software on something like this:
https://www.aliexpress.us/item/32568068 ... 00237956_2
You just have to compare the processors to see what you need.
they all use about 6W but the n150 has more power.
Re: DDOS - Entire Country of Vietnam banned
Posted: Sat May 17, 2025 3:54 pm
by linda.ljungdahl
Seems like most of the pictures getts http 500 errors on the openinverter wiki when you klick on them, is that related to this in any way?
/Linda
Re: DDOS - Entire Country of Vietnam banned
Posted: Sat May 17, 2025 3:59 pm
by linda.ljungdahl
is there a way to download the openinverter wiki database to browse it offline with kiwix?
/Linda
Re: DDOS - Entire Country of Vietnam banned
Posted: Sun May 18, 2025 7:48 am
by johu
linda.ljungdahl wrote: ↑Sat May 17, 2025 3:54 pm
Seems like most of the pictures getts http 500 errors on the openinverter wiki when you klick on them, is that related to this in any way?
Thanks for pointing that out. That must be caused by one of the recent updates though. Am looking into it.
Proton wrote: ↑Thu May 15, 2025 3:21 pm
If that server is at home you can install a PFsense firewall - Free software and then you can have lists added to known bad servers or IPs.
The forum runs on a hired server somewhere in Germany, so can't play with the hardware. I assume the PFSense Firewall could be installed on it?
Re: DDOS - Entire Country of Vietnam banned
Posted: Sun May 18, 2025 8:17 am
by johu
I installed MediaWiki 1.43.1 now and disabled the newly installed SemanticBundle (
viewtopic.php?p=82317#p82317). This was the last alteration 10 days ago and I'm afraid it may have broken things. The installation was very intrusive.
Re: DDOS - Entire Country of Vietnam banned
Posted: Sun May 18, 2025 6:25 pm
by Proton
johu wrote: ↑Sun May 18, 2025 7:48 am
The forum runs on a hired server somewhere in Germany, so can't play with the hardware. I assume the PFSense Firewall could be installed on it?
I am sure Iit can Be installed on a VM but not sure whatbis involved.
Re: DDOS - Entire Country of Vietnam banned
Posted: Mon May 19, 2025 9:41 pm
by johu
The requests are still going, now from China also. I will need to find a solution that automatically blocks an entire /16 subnet as soon as it detects too many requests from that same subnet. That is what I currently do manually.
Re: DDOS - Entire Country of Vietnam banned
Posted: Tue May 20, 2025 12:46 am
by Proton
johu wrote: ↑Mon May 19, 2025 9:41 pm
The requests are still going, now from China also. I will need to find a solution that automatically blocks an entire /16 subnet as soon as it detects too many requests from that same subnet. That is what I currently do manually.
can you limit the max connection per second from an IP address on your web server? You would think that the webhosting provider would give you that optinon.
Pfsense has a way to do that but you would have to make the pFsense your default gateway. Pfsense would need to have your public IP and your
webserver to be behind Pfsense.
"
1. Configuring Firewall Rules for DDoS Mitigation
pfSense's firewall rules are your first line of defense against DDoS attacks. By setting up specific rules, you can filter out malicious traffic and protect your network.
Block Malicious IPs:

Manually block known malicious IP addresses or use automated blocklists from sources like Emerging Threats. Navigate to Firewall > Aliases and add these IPs to a block list.
Restrict Traffic by Geographic Region:

Use pfBlockerNG to block traffic from countries that are not relevant to your user base. This reduces the risk of attacks originating from certain regions.
- Limit Incoming Connections:
Set up rules to limit the number of connections per second from a single IP address under Firewall > Rules > WAN. This helps mitigate floods from individual IPs.
2. Using pfBlockerNG for Enhanced Protection
pfBlockerNG is a powerful tool within pfSense that allows for advanced IP and domain blocking capabilities. It's essential for automated updates and enhanced DDoS protection.
Install pfBlockerNG:

Go to System > Package Manager > Available Packages and install pfBlockerNG.
Enable GeoIP Blocking:


Block traffic based on country using GeoIP filtering. This is especially useful for blocking traffic from regions where you don't expect legitimate users.
Automated Block Lists:

Configure pfBlockerNG to download and apply multiple IP block lists. These lists can focus on known malicious IPs, botnets, and other harmful sources.
Re: DDOS Attacks
Posted: Tue Jul 15, 2025 10:23 am
by johu
Since removing the firewall rules the DDOS picked up again. Their nature is that no single IP causes a lot of requests but rather many 100 or 1000 IPs create one request per second or so. So it is hard to distinguish from legit activity.
Currently looking into things such as "JavaScript Computational Challenge" that requires the browser to execute some javascript to put more load onto the attackers side or even block it out that way if it doesn't attempt to solve the challenge.
Re: DDOS Attacks
Posted: Tue Jul 15, 2025 6:00 pm
by Proton
SO you will have to find a way to rate limit the max connection per second from an IP address.
Re: DDOS Attacks
Posted: Wed Jul 16, 2025 9:12 am
by johu
Proton wrote: ↑Tue Jul 15, 2025 6:00 pm
SO you will have to find a way to rate limit the max connection per second from an IP address.
Like said, it cannot be told apart from legit access.
It got much worse today. I have to take drastic measures and completely disallowed guest access

Re: DDOS Attacks
Posted: Wed Jul 16, 2025 10:26 am
by Bigpie
Someone on discord suggested it may be AI scrapers gobbling up data. Have you checked the user-agent and other request data?
Re: DDOS Attacks
Posted: Wed Jul 16, 2025 11:46 am
by johu
Yes, some are but 99% of all requests are normal user agents such as "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_16_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36"
Edit: here is an example of some random /16 subnet
Code: Select all
170.231.140.241 - - [16/Jul/2025:13:47:30 +0200] "GET /forum/download/file.php?id=25675&mode=view&sid=f5f60d848d8760afa858553d19b70e52 HTTP/1.1" 403 3000 "-" "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.2309.372 Safari/537.36"
170.231.132.119 - - [16/Jul/2025:13:47:33 +0200] "GET /forum/viewtopic.php?sid=febc63cc02d433d02d876f224da41cd0&t=6365 HTTP/1.1" 200 3804 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2227.0 Safari/537.36"
170.231.235.243 - - [16/Jul/2025:13:50:12 +0200] "GET /forum/viewtopic.php?sid=93f5102039081d522462debbbbfdcffc&start=25&t=6256 HTTP/1.1" 200 3747 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Brave Chrome/89.0.4389.90 Safari/537.36"
170.231.141.35 - - [16/Jul/2025:13:50:23 +0200] "GET /forum/viewtopic.php?sid=17c8ee2fc1e7ef0308dbed8dce1a8fb6&t=5244 HTTP/1.1" 200 3730 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.79 Safari/537.36"
170.231.121.33 - - [16/Jul/2025:13:50:39 +0200] "GET /forum/ucp.php?mode=privacy&sid=43d38fd160aa14d38afe8d2186079286 HTTP/1.1" 200 4185 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.69 Safari/537.36"
45.170.231.139 - - [16/Jul/2025:13:50:59 +0200] "GET /forum/viewtopic.php?sid=686153c0bfb423971d193c6e7d1f6180&t=4743 HTTP/1.1" 200 3798 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.80 Safari/537.36"
170.231.133.78 - - [16/Jul/2025:13:51:02 +0200] "GET /forum/viewforum.php?f=5&sid=d1cb8be08a4d06784fe32f1dbc22eb77 HTTP/1.1" 200 3798 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36"
170.231.122.199 - - [16/Jul/2025:13:51:02 +0200] "GET /forum/viewtopic.php?sid=7064eec68510c6210693e07283afa83f&t=6494 HTTP/1.1" 200 3796 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36"
170.231.132.235 - - [16/Jul/2025:13:51:11 +0200] "GET /forum/search.php?sid=175be1ebcf71add40421c8016447bfbd HTTP/1.1" 200 2978 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36"
170.231.143.67 - - [16/Jul/2025:13:51:16 +0200] "GET /forum/viewtopic.php?p=60153&sid=ca237265be2cb00c3f4a02c6610ef57f HTTP/1.1" 200 3797 "-" "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.0.0 Safari/537.36"
170.231.28.110 - - [16/Jul/2025:13:51:59 +0200] "GET /forum/viewtopic.php?sid=85599218f4968cf7271dd71adfb3c412&start=25&t=2322 HTTP/1.1" 200 3746 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_3) AppleWebKit/537.36 (KHTML, like Gecko) Brave Chrome/89.0.4389.114 Safari/537.36"
There a long delays between requests and in the 5 minute period the same address never shows up twice
Re: DDOS Attacks
Posted: Thu Jul 17, 2025 3:42 am
by projectgus
FWIW, AI scrapers are crippling small web servers worldwide at the moment. They're sophisticated enough to use different IPs and common browser user agents. If no one has yet tried to extort money from you to stop it then it's most likely scrapers and not an "intentional" DDoS.
A lot of open source sites have installed
Anubis to limit access to real browsers. Take a look at this usage graph for an idea of the impact:
https://mastodon.social/@dbaio/114820378778350969
(If you don't want to go open source then there's always Cloudflare, etc. on the corporate end.)
Re: DDOS Attacks
Posted: Thu Jul 17, 2025 4:54 pm
by johu
That seems to hit the nail on the head

Thanks very much, will try it when I get the chance to
Re: DDOS Attacks / AI botfarm overload
Posted: Sun Jul 20, 2025 3:38 pm
by johu
Installed Anubis. Database server load decreased from 200% cpu usage to hardly anything
Lets see if there are adverse effects, i.e. TOR users no longer able to access the site or so
EDIT: tested. Still works over Tor
Re: DDOS Attacks / AI botfarm overload
Posted: Sun Jul 20, 2025 4:28 pm
by Bigpie
I'm no longer able to access with Brave Browser.
Re: DDOS Attacks / AI botfarm overload
Posted: Sun Jul 20, 2025 7:47 pm
by johu
I'm using Brave as well and had a recusrsion problem. Try deleting cache and cookies
Re: DDOS Attacks / AI botfarm overload
Posted: Sun Jul 20, 2025 9:37 pm
by TassieDevil
Bigpie wrote: ↑Sun Jul 20, 2025 4:28 pm
I'm no longer able to access with Brave Browser.
I had the same problem.
Johu, I was looking at Anubis for my own use. Do you have to use it with a reverse proxy? I don't use one, just Apache. Edit: looks like it is required.
Re: DDOS Attacks / AI botfarm overload
Posted: Mon Jul 21, 2025 6:45 am
by johu
I followed this:
https://anubis.techaro.lol/docs/admin/installation/
I did a native install but probably Docker is the preferred method.
I'm running nginx here. One thing that wasn't mentioned in any manual:
I the frontend server (the one receiving requests on ssl port 443) I had to specify
Code: Select all
proxy_redirect http://openinverter.org:8090 https://openinverter.org:443;
As otherwise http redirects would send you to the none-reachable internal server.
For a similar reason where php fpm is linked to nginx I had to specify
Code: Select all
fastcgi_param HTTP_HOST openinverter.org;
as again some php scripts use HTTP_HOST to assemble urls. On the forum for example the gallery images weren't visible because they linked to "localhost"
I'm sure you'll need to do something similar in apache to overcome these limitations.
Re: DDOS Attacks / AI botfarm overload
Posted: Mon Jul 21, 2025 7:35 am
by Jacobsmess
Brave works fine for me
Re: DDOS Attacks / AI botfarm overload
Posted: Mon Jul 21, 2025 9:12 am
by Bigpie
johu wrote: ↑Sun Jul 20, 2025 7:47 pm
I'm using Brave as well and had a recusrsion problem. Try deleting cache and cookies
This worked. Now able to access again.