Ask HN: Best Way to Mess with Hackers?

[AJRF]

I am watching my fail2ban logs on my servers and while this tool is fine and will probably annoy them a little, is there a more fun way to mess with these people?

I can see from the failed attempts that are trying to curl the kiss a dog cryptojacking software, so they aren't simply probing my server - they are trying to cause harm.

Preferably legal. Making them lose money would be great too!

[DamnInteresting]

The donation form on my site was recently being inundated by some card tester (person/group who have a huge list of stolen credit cards, and they try making $1 donations with each card to see which cards still work). They were making around 10k attempted fraudulent donations per hour from a huge pool of IP addresses.

Rather than simply blocking them, whenever I detected a card tester, I started sending them random results that mimic real-world results. About 98% of the time, I sent a false "card failed" error, with varying reasons for the failure. And about 2% of the time I sent false "donation successful" messages.

It went on like that for weeks. I was giving them complete garbage data that they seemed to be accepting, so I assume I was completely wasting their time and effort, and possibly getting them in hot water with the shady clients who buy the lists of "working" cards.

I finally got sick of the ongoing DDoS and started replying to them with SQL injections, like:

> '; DROP TABLE users; --

> '; DROP TABLE user; --

> '; DROP TABLE credit_card; --

...and so on. My thinking was that they might not be sanitizing the inputs on their end, replies from a CC processor would be an unexpected vector for SQL injections.

The card testing stopped just after that, either because the change tipped them off, or because I managed to guess one of their table names and caused hilarious destruction of data.

[qualudeheart → DamnInteresting]

Brilliant. My friend Timothy works in infosec. I will show this to him. Thank you for sharing this with us.

[cypherg]

make an ssh honeypot (in docker) that is extremely limited in speed/bandwidth. Have only one small binary in the home folder called "PASSWORD_STORAGE" that has no execute permissions. Hopefully someone will download the binary to their own machine an execute it. Instead of a benign file, "PASSWORD_STORAGE"should be a disk encryptor/drive wiper.

[askiiart → cypherg]

I don't think that's quite legal, but I can't say I'm not a fan.

[alain_gilbert → askiiart]

I don't see what is illegal in putting whatever you want on your own server...

[no_time → alain_gilbert]

In the same way that poisoning wine that has been stolen before is illegal, atleast in my country. I dont agree with this ruling either. I hope the USA is more just in the regard.

https://444.hu/2013/11/04/fagyallo-bor

[askiiart → no_time]

As for the USA, it seems like it would be a similar case to the one of the shotgun booby trap. [0]

[0] https://youtu.be/bV9ppvY8Nx4?t=1027

[LinuxBender]

fun way to mess with these people?

To some extent yes, give them a status 200 for anything they send at you, especially for your default catch-all domain/IP/virtual-host. In NGinx this looks like

    error_page 404 500 501 502 503 504 =200 /some_generic_message.html;

I would personally just disable fail2ban. It just consumes more CPU especially if using it with iptables. If using ip route blackhole {ip} its not as bad but still a waste of time in my opinion. There are enough known compromised hosts out there to add millions of entries to your routing table ahead of time. [1]

Add headers and content to the generic message file that has links to URL's like WordPress, wp_login.php, wp-story.php, js/file-uploader, nf_tracking.php, about.php, wp-reset.php and others. To minimize writes on your disk, set custom logs for your default virtual-host/IP/domains to either write into a tmpfs ram disk or to /dev/null once you get bored watching them. If writing to tmpfs be sure to set up a more frequent log rotation and less retention. Be sure to also set the HTTP keepalive time very low so they are not wasting your resources. No need to tarpit them, most of the code used by these bots will time out after a few seconds.

[Edit] I should add, these are not hackers you are messing with. They are just parasitical script-kiddies that prey on the weak, most often using their batches of WordPress hosts as jump-off points and watering hole phishing sites to scam the elderly out of their life savings.

Making them lose money would be great too!

That's much harder. Most of the IP's you see do not belong to the attacker. The attacker is likely using a set of Command and Control C&C nodes that control a swath of end-user PC's and Wordpress servers infected with malware. Anything you do will cost them nothing but it might slow their threads down a little. The only way to make them lose money would be to find who is controlling the C&C nodes, gather evidence and have law enforcement take them down. To do this one would have to break the law by hacking into the compromised host and see what C&C nodes it is dialing home to, then hack into those hosts and see who is connecting to them. They could be using Tor but most people are lazy enough to not do this.

[1] - https://github.com/firehol/blocklist-ipsets.git

[aww_dang]

Set gzip encoding, respond with gigabytes of gzipped zeroes.

https://en.wikipedia.org/wiki/Zip_bomb

There's more you can do when they actually parse documents. XML + XSLT can overflow some systems. Even just a deep html document tree can use up resources.

[LinuxBender → aww_dang]

That's a fun one. Also 32GB favicon.ico's for the default catch-all host/IP assuming one is OK with the extra bandwidth usage.

[colanderman → aww_dang]

Straight XML often suffices, no XSLT needed: https://en.m.wikipedia.org/wiki/Billion_laughs_attack

[ROTMetro]

Post that you are releasing your source code as free while releasing it under the GPL license not BSD/MIT. That will make them go ballistic :)

[hayley-patton]

Any pathnames associated with WordPress on my web server redirect to https://youareanidiot.cc/ - hopefully that's enough of a false positive to waste their time.

[samjanis → hayley-patton]

WARNING:

I clicked the above link and had to chase a growing population of 10+ popups.

Hilarious.

p.s. I do have a popup/JS blocker, but disabled it last night to test something else.

[return_to_monke]

if you have people wanting SSH, there's this:

https://github.com/skeeto/endlessh

[JZerf → return_to_monke]

Tarpitting in general can be fun. I have an iptables rule set up on my mail server that limits incoming SMTP traffic from suspected spammers to just three packets per minutes (which is still fast enough for a legitimate mail server to deliver your typical, less than 250 KB email in under an hour in case you accidentally ensnare a legitimate sender) and I've seen it often tying up spammers for 15+ minutes at a time. Below is a sample of a rule I might use in case anyone else is interested:

  iptables --append INPUT --source 1.1.1.1,1.1.1.0/24 --protocol tcp --dport smtp --match hashlimit --hashlimit-name HASHES_FOR_PROBABLE_SPAMMER_THROTTLING --hashlimit-mode srcip --hashlimit-above 3/minute --hashlimit-burst 1 --jump DROP

[moomoo11]

If someone tries to find your .env (obv I’m not dumb enough to expose it) have it ddos the originator instead.

[kurisufag]

generally speaking, most people that run botnets are dumb kids (I know I was), so popping one of the boxes should both be fairly easy and point you at a c2 of some kind.

at which point you can report it to the host/attack it/whatever.

[nszceta]

Low Orbit Ion Cannon (LOIC)