ActivityPub API Client Reputation
Technical Discussion
7
Posts
4
Posters
8
Views
-
For the ActivityPub API Task Force, I started an issue to discuss OAuth client reputation systems.
A reputation system tracks which OAuth clients are known good, known bad, or unknown. Servers could use this information to limit what clients can do. For example, a server could prevent users from logging in with a known bad client.
The reputation could be based on human curation and review, or on automated collection of evidence from historical behaviour of the client.
I'm trying to find examples in the OAuth ecosystem of this kind of reputation systems -- either local or distributed.
App store approval (and user reviews) are a good example for native apps. OpenBanking keeps a client directory that needs human curation and review.
I don't have examples from OAuth -- especially with dynamic registration or CIMD.
Any ideas?
-
undefined evan@cosocial.ca shared this topic on
-
@evan@activitypub.space I want to take a moment to note how nice the NodeBB content looks in Mastodon.
-
@evan what factors would impact the reputation and who decides what is a good or bad client?
-
I'd suggest that there are two parties that should get to decide what is a good or bad client:
- The ActivityPub user who uses the client.
- The administrator of the server that the ActivityPub user uses.
I think there's a third group, which is other admins, developers, and users, who share similar values with the user and the admin. They may have information to share with the user and/or admin.
I don't think these values are universal, so I don't think we need a universal reputation. But I can give what I think are bad things for an API client to do.
- Generating activities on behalf of the user that don't match the user's express or implied intentions. For example, if the user logs into a client app, and it posts a public message, "I think this client app is the best and everyone should try it!"
- Extracting the user's data for reasons that the user wasn't informed of. For example, a client app that copies all your private messages to cloud backup controlled by the app developer.
- Abusing public or private resources, even if the user intends to abuse. For example, a client app for spamming, or a client app for brigading.
I think there are a few signals that could identify what I would call "bad" clients:
- User complaints would be the biggest
- Complaints from other users about the user's behaviour when using the app
- Security researcher reports
-
@evan
Sounds good!I suppose it would be useful to be able to specify the version too so that you may ban a known buggy version of a client or any version prior to a known CVE fix.
It could also be useful to make those lists shareable so that a new Fedi instance can start with something if they wish to.
-
Client reputation isn't really something you can track and share in a decentralized network without introducing some centralisation. You could try to do web of trust style things, but that would mean writing a record that publicly says "good client is good", but then a malicious app could just write that record on sign-in: how many iOS apps nag you for a positive review? Particularly with somewhat dark patterns of "are you enjoying ? Yes / no" where "no" pushes you to the app's feedback and yes pushes to write a review, trying to deliberately avoid negative reviews.
The other downside of publicly disclosing which clients you use is that it tells attackers where to look for security exploits, because now you can pick a set of targets and try to attack the software they use.
Raw usage numbers also doesn't help because a bad client can quite easily become viral, see for example Cambridge analytica, who iirc used games to gain access to sensitive data.
You'd also need moderation tools that can moderate clients in some sort of meaningful way ā that's near impossible for dynamic client registration. That's why we wrote the CIMD spec. A large Mastodon server usually has 10-20x the number of registered clients as number of accounts.
Things that can add up to trust are things like:
- privacy policies & terms of service
- client_uri (website) matching the client metadata (requires some crawling)
- client authentication mechanism (public client vs private_key_jwt auth)
- scopes/authorization requested being fine grain enough, instead of asking for full unrestricted access.
But OAuth security and trust models are complex and generally proprietary
-
undefined informapirata@mastodon.uno shared this topic on
-
@thisismissem said in ActivityPub API Client Reputation:
> Client reputation isn't really something you can track and share in a decentralized network without introducing some centralisation.I think that some centralisation is fine, as long as admins or even users can choose their reputation data provider. We do this with blocklists for instances already; there's no reason to think that client blocklists would need to be any different. They'd have to have the same caveats; a trusted provider, transparency in the process, etc.
> You'd also need moderation tools that can moderate clients in some sort of meaningful way ā that's near impossible for dynamic client registration.
Agreed. The best I can think of is using the
redirect_uri, but that's not really unique -- especially for command-line clients that uselocalhost!I think the ticket you're working on for moderating OAuth clients for Mastodon is a really big deal. I think it'd be a similar issue for ActivityPub API clients.
> That's why we wrote the CIMD spec.
Yes! Using the same identifier for clients in a verifiable way is a big help in having a reputation for using on a single server or multiple servers.
> But OAuth security and trust models are complex and generally proprietary
I think you could get to some pretty useful metrics pretty quickly, though. Some good ones to use might be:
- How many people on this server (or other servers) have authorized the client
- What the average rating has been (but you need a way to rate clients!)
- How many
Flagactivities have been submitted for this client (you need a way to report clients) - Reviews of the client (you need a way to write a review of a client)
That data could be local to the server, or could be shared from other trusted servers. A trusted intermediary like IFTAS could be helpful.
Gli ultimi otto messaggi ricevuti dalla Federazione
-
@js@podcastindex.social thanks! š¤
-
@julian hmm, I believe it tries to make each AP call from the browser first, then falls back to a cloudflare worker if that fails.
I just checked the cf worker and found this gem in it, so that might work for you too
-
I've seen hints of backfill working really well, but hadn't seen good examples until recently. As more and more instances upgrade to the newer versions of Mastodon that support context, backfill from Mastodon instances will improve across the board.
Today one of the most popular topics on my NodeBB instance was an update from the admin of The Forkiverse, a brand new up-and-coming instance. Despite following only one person from that instance, I was able to see every single reply from that instance, even from users I don't follow.
Super stoked to see resolvable contexts and backfill working in the wild. Who says the Fediverse is quiet? Not me, anymore š
-
Hi @silverpill@mitra.social right;
Move and Remove are explicit actions concerning membership of a context in an audience. Update is overly broad and receivers would have to infer audience change based on what the updated object contains (e.g. Audience Y is suddenly missing, and Z is new, was this always the case?) It is likely that sending audience as an array will not be correctly interpreted by existing software, so this property is an unreliable indicator of context audience membership at best Existing threadiverse apps check addresses, and audience may not be used at all in some.There is no conflict with Move(Person), and I have not heard a convincing reason to adopt a new activity type when these two AS activities work quite well to describe what we want to accomplish.
-
Hm, it appears that none of my objections have been addressed.
Once again, why there are two activities Move and Remove, and not a simple Update or a new activity type?
-
Hey @js@podcastindex.social, I enabled Anubis for my site, but now requests from Browser.pub don't work :cry:
Is there something I can write a rule against, perhaps a header or user agent string that is unique to browser.pub?
-
@thisismissem said in ActivityPub API Client Reputation:
> Client reputation isn't really something you can track and share in a decentralized network without introducing some centralisation.I think that some centralisation is fine, as long as admins or even users can choose their reputation data provider. We do this with blocklists for instances already; there's no reason to think that client blocklists would need to be any different. They'd have to have the same caveats; a trusted provider, transparency in the process, etc.
> You'd also need moderation tools that can moderate clients in some sort of meaningful way ā that's near impossible for dynamic client registration.
Agreed. The best I can think of is using the redirect_uri, but that's not really unique -- especially for command-line clients that use localhost!
I think the ticket you're working on for moderating OAuth clients for Mastodon is a really big deal. I think it'd be a similar issue for ActivityPub API clients.
> That's why we wrote the CIMD spec.
Yes! Using the same identifier for clients in a verifiable way is a big help in having a reputation for using on a single server or multiple servers.
> But OAuth security and trust models are complex and generally proprietary
I think you could get to some pretty useful metrics pretty quickly, though. Some good ones to use might be:
How many people on this server (or other servers) have authorized the client What the average rating has been (but you need a way to rate clients!) How many Flag activities have been submitted for this client (you need a way to report clients) Reviews of the client (you need a way to write a review of a client)That data could be local to the server, or could be shared from other trusted servers. A trusted intermediary like IFTAS could be helpful.
-
@bentigorlich@gehirneimer.de in the relevant issue in Mbin's issue tracker raises a wording concern: "resolvable context" is an unfamiliar term to those who have not read through FEP 7888.
I will update the FEP to make this definition more explicit.
https://github.com/MbinOrg/mbin/issues/248#issuecomment-3741019183
