Automatic detection on lichess.com

[radicalmunchkin]

I went on lichess recently and saw that I had been shadowbanned. I then spoke to support and I learned that an extension was flagged by lichess. I'm pretty sure this extension was somehow flagged and it wasn't due to reports since I usually use it on bots. I use Firefox and have it installed with ViolentMonkey.

[Hakorr]

They should not be able to detect A.C.A.S directly unless you had the moves displayed on Lichess, in which case it could be theoretically possible to detect it but I haven't seen any source code indicating such detection yet, granted I check that not logged in against bots. Without the moves displayed on the page, A.C.A.S should only read the page meaning it shouldn't be possible for the page to detect it.

If they shadowbanned you for having Violentmonkey installed, then you should be able to argument that it's just a general extension and doesn't mean you're cheating. Also, detecting installed extensions is tricky and sites cannot very easily do that if at all, so its questionable if they actually detected your extensions, maybe they just use the term "extension" for any page altering or reading scripts.

There could also be a possibility they say that to everyone who is detected using engines. Extensions meaning any external assistance you've received. Their AI chess cheat detection system based purely on your playing style and moves made is decent.

[radicalmunchkin]

If they shadowbanned you for having Violentmonkey installed, then you should be able to argument that it's just a general extension and doesn't mean you're cheating. Also, detecting installed extensions is tricky and sites cannot very easily do that if at all, so its questionable if they actually detected your extensions, maybe they just use the term "extension" for any page altering or reading scripts.

I’m pretty sure they detected some kind of script on the site, because they only allow visual extensions and not ones that run scripts. For example changing the chess piece font.

[Hakorr]

If you had played games on that account with assistance previously, I'd say the probability of them just analyzing your game and determining you received some kind of external assistance is great enough to be the reason for the shadowban. The "banned for using an extension" could mean almost anything unless they directly mention Violentmonkey or A.C.A.S. This kind of ban cannot be bypassed without playing like a human consistently.

[radicalmunchkin]

It’s not based on an analysis of my games, they told me they detected an extension and told me that only css extensions are allowed.

[Hakorr]

It’s not based on an analysis of my games, they told me they detected an extension and told me that only css extensions are allowed.

Ask them what extension they detected.

[radicalmunchkin]

They were being very vague, and I think my account was simply flagged. I managed to get them to believe the flag was due to an arbitrary automatic en passant extension but I’m still unsure of whether or not I should use A.C.A.S. on lichess.

[Hakorr]

The terms of service states you should not use A.C.A.S on online matches. You will eventually get banned if you only follow the moves it suggests. If you use it to learning purposes, don't display moves on the page and play by yourself, it should not be bannable nor detectable.

Also the fact they believed it was another extension indicates they did not directly detect A.C.A.S.

[radicalmunchkin]

I don’t use every engine recommended move, I’m very careful when and where I use it. I’m sure they just detected an application in some way. I don’t know if they detected ACAS or the ViolentMonkey extension, but I’m pretty sure the anticheat flagged something.

[Hakorr]

I don’t use every engine recommended move, I’m very careful when and where I use it. I’m sure they just detected an application in some way. I don’t know if they detected ACAS or the ViolentMonkey extension, but I’m pretty sure the anticheat flagged something.

I searched through the source code and while there is a great chance I missed something, I have not found such detections. Most anti-cheat related code is focused on analyzing the playing style. Even if you think you used very little assistance, it could alter your playing enough to trigger the detections.

Violentmonkey cannot be the reason for the ban as,

1. It's basically impossible to detect installed extensions on most browsers. The ways are hacky at best.
2. Browser extension detections would violate the privacy of the users. (Lichess community gets mad)
3. Even though it was detected, Violentmonkey is just not bannable.

This means they would have a specific check for A.C.A.S. Sites cannot detect running userscripts unless the userscripts modify the document (just reading the document is not detectable). The only A.C.A.S feature which should expose itself like that is the "Moves On External Site", which adds an SVG element to the document.

Now while on paper it's possible to detect, implementing a detection for it would be a bit hacky and lead to false positives in the future if the site adds similar elements itself, or some other extension adds their own stuff to the document. Not really a reason to immediately ban someone.

If you have more information I'm happy to hear it. I don't want users getting banned for just having A.C.A.S installed since there are legitimate use-cases for it and I'll try to add more educational features in the future. Just know that without the "Moves On External Site" activated and while actually playing by yourself, it should be impossible for you to get banned.

[radicalmunchkin]

Yeah, I’m making sure not to use the display moves on page anymore, although it doesn’t automate anything or is a risk I’ll still do it just to be careful. I know you probably understand much more about this than me.

[Hakorr]

Yeah, I’m making sure not to use the display moves on page anymore, although it doesn’t automate anything or is a risk I’ll still do it just to be careful. I know you probably understand much more about this than me.

I often find myself being an idiot, so I wouldn't really count on my understanding, haha. If I start receiving similar reports then I'll have to look into the subject a bit more, but right now I have heard no one with a similar issue, although most of the users play on Chess.com.

[radicalmunchkin]

Alright, hopefully this is just a little rare occurrence, thanks for responding so quickly and being such a help, have a great weekend man 👊❤️