How the FSF sysadmins block botnets with reaction (fsf.org)

129 points by pseudolus 3 days ago

idoubtit 3 hours ago

That's interesting. I haven't used fail2ban for a long time, but reaction is worth evaluating. Unfortunately, that post does not describe their full configuration. Maybe it's on purpose, so that attackers can't adjust to fit.

My experience is that modern web scraping had no obvious pattern, since it is proxied through many IPs. The last time a server was failing to handle the pressure, we decided to temporarily ban IPs from some Asian regions. How does the FSF decide to ban an IP?

Why do they use iptables + ipset instead of nftables? Is there a technical reason or is it just legacy? AFAIK, Nftables is more performant, and IMO simpler. And it has native sets, see https://wiki.nftables.org/wiki-nftables/index.php/Sets

itintheory 2 hours ago

> The last time a server was failing to handle the pressure, we decided to temporarily ban IPs from some Asian regions.

This is something we've been forced to do at work, a LOT. Some weeks it's Huawei Cloud, Tencent, and Alibaba. Other weeks it's all China Telecom. We're using Anubis where possible, but a lot of it is just whack-a-mole with residential proxies. I looked at Datadome and HUMAN, but they would be hundreds of thousands a year at our traffic scale, and I suspect may also have false positives. We abandoned CrowdSec for that reason as well.

I'd love to find a decent k8s native solution to this problem.

thomzane an hour ago

iptables has been mostly a wrapper for nftables for some time now. The choice of iptables + ipset with reaction is the difference in their configuration. Compare restart performance between the ipset and nftables example configurations with lists of greater than 1 million IPs.

Bender 3 hours ago

My personal preference is to 'ip route add blackhole ${net}' as it has the lowest CPU overhead and I can add hundreds of thousands of CIDR blocks with no noticeable impact. The only downside is that it won't stop UDP packets from getting to a UDP listener. There will not be a response but the application will still see it. For my TCP daemons it's great.

    grep -m1 -E ^Tot /proc/net/fib_triestat ;ip route | grep -Fc blackhole
    Total size: 56735  kB
    426951
Those 426951 blackhole routes include data-centers, VPS providers, botnets, AI datacenters that ignore robots.txt, search engines, abused CDN's, known bad residential nodes and much more. I still see a few residential proxy bots that do a halfway decent job of pretending to be real people at times but the feds are playing whack-a-mole with them. The bots self report to my silly blog so I can block them elsewhere on systems I might care a little bit about. Happy to share them if anyone is remotely interested.

I also use a couple generalized rules in nftables raw table that keeps a lot of beyond poorly written bots away including hping3 tcp floods and masscan. My rules to port 443 are stateless. One must not taunt the state table.

seki285 2 hours ago

I would like to learn more how you maintain your table of IP ranges (or CIDR block). How do you decide when to add/remove a range?

I'm most concerned about blocking innocent users, currently I use Cloudflare to block known bad ASNs using a list I found on GitHub.

Bender 2 hours ago

How do you decide when to add/remove a range?

The only IP's that come and go are the Tor 30 day blocklist and a couple FireHOL attackers from a repo though I will sometimes leave the last entries live until reboot. I do not really need to block tor but I use this silly blog as a testing ground. Tor and some known abusers come from a git repo I refresh periodically.

The data-centers, VPS providers, CDNs, known botnets are perma-banned. For my hobby nodes I personally find this acceptable. I would not do this in a professionally managed data-center. There are better methods for those cases especially for B2B corporate arrangements. Regardless of what daemons I run I never have external dependencies that need to be accessed from my node or from the client with exception of stratum-1 time servers.

I do have to periodically update the CIDR blocks for given ASN's. I have not automated this but I probably should some day. It's not hard to automate, I am just excessively "efficient". I was told to stop calling myself lazy, but I am.

Methods 2, 3 and 5 are the ones I talk about here. [1]

[1] - https://nochan.net/b/Internet-Crap/20260606-How-To-Block-Som...

Magicrafter13 3 hours ago

> This software is gay, trans and anticolonialist. If you're uncomfortable with that, please don't use it

Weird message to include in AGPLv3 licensed software (which explicitly allows people to use software however they like, regardless of their beliefs or feelings).

fluoridation 22 minutes ago

My Gen Y brain can't read the phrase "[inanimate object] is gay" without interpreting it as disapproval.

Groxx 3 hours ago

You can have preferences while not restricting legal rights.

graemep 2 hours ago

You can, but if the exact quote in the GP is correct the claim is claiming the software is "gay, trans and anti-colonialist" and asks you not to use it. Why use a license that is designed to be politically neutral and then ask some people not to use it?

What I can see is a fairly clear indication that they do not want contributions from people whose politics differ from theirs. I would also question whether government funding of a project with political policies about who can participate is appropriate. The political stance is also rooted in a particular culture so is unwelcoming to people from other cultures.

Of course people can political views and preferences, but they presumably have some aim in mind when making that statement in the README. What is that aim?

Groxx 2 hours ago

BigTTYGothGF 2 hours ago

stonogo 2 hours ago

wasmperson 3 hours ago

It's somewhat interesting to see the FSF's approach to this. From what I understand they can't really use something like anubis since they want their websites to be accessible without javascript:

https://www.gnu.org/philosophy/javascript-trap.html

Users can't consent to running a page's javascript the way they can consent to running a program they've intentionally downloaded, so it's effectively "non-free" regardless of license.

xena 2 hours ago

For what it's worth, Anubis supports LibreJS: https://github.com/TecharoHQ/anubis/blob/main/web/build.sh#L...

BigTTYGothGF 2 hours ago

superkuh 2 hours ago

Anubis does support the no-JS HTTP meta-redirect proof of work but few know about it and fewer enable it. And it may not block everything.

wasmperson 2 hours ago

I indeed did not know about this. There seem to be some caveats:

https://anubis.techaro.lol/docs/admin/configuration/challeng...

I guess for the meta refresh challenge it's less "proof of work" and more "proof of patience".

xena 2 hours ago

nubinetwork 3 days ago

> We placed our regular expressions in fail2ban, and found that we were hitting the maximum rules that could be added to UFW firewall rules on our systems which showed degradation around 65,000 rules

Firewalld had a similar issue up until recently as well.

jruohonen 3 hours ago

m3047 2 hours ago

"Many sysadmins know about fail2ban..." and many will now know about reaction. But why will the result be any different than fail2ban? It won't.

I identify features (which can be expressed as firewall rules) from log data; I write totals to a temporary store (Redis). I have periodic tasks which scan the temp store for patterns which exceed thresholds. When that occurs, fail2ban creates the appropriate rules. This occurs in depth and in concentric rings.

Et tu?

thomzane an hour ago

The difference between fail2ban and reaction is performance. If you are not hitting the ceiling of fail2ban, then you may not need reaction.

Do you have a blog post about your automated fail2ban rule generation?

charcircuit 2 hours ago

>Popa botnet

It's no more of a botnet than ProtonVPN for example. Apps intentionally added the Popa SDK to their apps as a monetization method. This allows apps without ads and tracking to be financially viable. I would expect FSF to support apps being able to move off of monetization schemes that depend on tracking people so it is disappointing for them to put such alternative monetization technologies in a negative light.

thomzane an hour ago

This monetization scheme benefits the botnet controller and the developer who added the SDK and not the user who likely did not realize they signed up to become an exit node.

cyanydeez 3 days ago

are scrapers attackers?

I get they're DDoS; but take the mask off, and arn't they just the AI monied interests that fund the FSF? and a lot of them are just active inference, eg, the user is trying to ask about something and the AI monied interests setup a web scraper to go and get that data.

Just seems like no one wants to call out the hand that feeds them in a human centipede that's best described as the torment nexus.

m3047 2 hours ago

Anything which fills my logs with garbage is unwanted. Your cat could have fallen asleep on the keyboard, I don't care. If you want to use the internet as a giant petri dish, that's on you; but the cat box is elsewhere. I can feed you garbage or block you because your code is shit, or I don't like your style.

nemomarx 3 hours ago

instead of scraping then, they could pay the fsf for a dump of the site or some API access or something, right? why overload the servers normally.

GoblinSlayer 3 hours ago

That's what commoncrawl does.

nemomarx 3 hours ago

kaladin-jasnah 3 days ago

> AI monied interests that fund the FSF

Can you elaborate on who these interests are precisely?

cyanydeez 2 days ago

I tried: https://www.fsf.org/patrons; the last FY listed is 2020.

kaladin-jasnah 2 days ago

thomzane an hour ago