Ray,For clarity, we will roll back the current restriction of 15 calls per user per hour to account/verify_credentials, and implement the proposed scheme:
> ... we will limit the total number of unsuccessful > attempts to access authenticated resources to 15 an hour per user per IP > address. If a single IP address makes 15 attempts to access a > protected resource unsuccessfully for a given user (as indicated by an HTTP 401), > then the user will be locked out of authenticated resources from that > IP address for 1 hour. Thanks, Doug On Wed, Jul 29, 2009 at 9:51 AM, Ray <rvizz...@testlabs.com> wrote: > > Doug, > > I'm in a similar situation as that voiced by TinBlue. This change has > affected our iPhone App. We also want to encourage you to rollback > this change ASAP. > > When you say "This approach is what we are going to take.", do you > mean rolling back the fix so as not to affect multiple, successful, > authorized logins? I'm hopeful that "this approach" means that our > apps will not be affected yet again by changing to a new auth > approach. > > I appreciate you all keeping this thread informed. > > Ray > > On Jul 27, 11:23 am, Doug Williams <d...@twitter.com> wrote: > > Thanks to everyone who has contributed feedback. This approach is what we > > are going to take. > > Alex will be making this change shortly. I will update this thread when > > there is timeframe to share. > > > > Thanks, > > Doug > > > > > > > > On Mon, Jul 27, 2009 at 7:52 AM, TinBlue <tinb...@gmail.com> wrote: > > > > > What is happening? > > > > > This rollback is taking far too long for something that has affected a > > > lot of people! > > > > > On Jul 25, 2:32 pm, Dewald Pretorius <dpr...@gmail.com> wrote: > > > > Doug, > > > > > > I would prefer to adopt OAuth instead of writing code for Basic Auth. > > > > > > So, you guys need to move OAuth out of public beta into full > > > > production sooner rather than later. :-) > > > > > > I manage 100,000+ Twitter accounts, and I simply cannot take on the > > > > support workload of answering user tickets when there's a snag with > > > > OAuth beta. > > > > > > I monitor these forums and the API Issues and still see too many > OAuth > > > > issues being reported to give me a level of comfort that I can safely > > > > switch over to OAuth. > > > > > > On Jul 24, 5:46 pm, Doug Williams <d...@twitter.com> wrote: > > > > > > > Well said Joshua. > > > > > > > Dewald, you have identified the risk of using basic authentication. > If > > > > > your users being locked out due to malicious behavior, you should > > > > > either implement further user-level rate limiting on your side or > > > > > adopt OAuth. > > > > > > > Are there any other glaring omissions in our thinking or should we > > > > > proceed with this as our solution? > > > > > > > Thanks, > > > > > Doug > > > > > > > On Fri, Jul 24, 2009 at 11:08 AM, Joshua Perry<j...@6bit.com> > wrote: > > > > > > > > Jim's concern is valid, fortunately OAuth is immune to > brute-force > > > attacks > > > > > > once the access key has been issued to an application. For this > > > reason alone > > > > > > I would urge people to switch to OAuth if at all possible. I > would > > > hope > > > > > > (and assume) that if login attempts for an account are locked out > > > that a > > > > > > user would still be able to successfully use an already > authorized > > > OAuth > > > > > > driven application. > > > > > > > > Unfortunately allowing a successful un/pw login while an account > is > > > locked > > > > > > out even when the correct password is presented effectively > bypasses > > > the > > > > > > whole reason for a lockout in the first place, preventing > brute-force > > > > > > password attempts. If an attacker used a dictionary or > brute-force > > > attack > > > > > > and the account was locked out after 15 attempts, then they could > > > continue > > > > > > trying even though the system replied "locked out"; if they > > > eventually sent > > > > > > the correct password it would just bypass the lockout and they > would > > > then > > > > > > know the correct password. > > > > > > > > Perhaps Twitter could implement a selective captcha, I know they > are > > > > > > annoying but if executed properly it could be effective > protection > > > against > > > > > > brute-force and dictionary attacks. Say after 3 or 4 failed > attempts > > > without > > > > > > a captch the API would then include a captcha image URL in it's > > > response > > > > > > that the application would then need to show to the person and > > > include the > > > > > > user's response with the next authentication attempt as a header > or > > > POST > > > > > > variable. The site stackoverflow.com does this to great effect, > if > > > you > > > > > > create posts quicker than a certain threshold which a person > would > > > not > > > > > > exceed then they pop a captcha up, in the normal use of the site > you > > > will > > > > > > never see one; I've only hit two captchas in the last in the last > 8 > > > months > > > > > > using the site. > > > > > > > > Josh > > > > > > > > Dewald Pretorius wrote: > > > > > > > >> Jim raised a huge weakness with the authentication rate limiting > > > that > > > > > >> could essentially break third-party apps. > > > > > > > >> Anybody can try to add anybody else's Twitter account to a > > > third-party > > > > > >> app using an invalid password. If they do that 15 times with a > > > Twitter > > > > > >> account, the real owner of that Twitter account, who may have > added > > > > > >> his account a long time ago with the correct password, is locked > out > > > > > >> from using that app for an hour. > > > > > > > >> I believe you will absolutely have to reset / remove the lock as > > > soon > > > > > >> as the Twitter account uses the correct password. > > > > > > > >> On Jul 22, 4:58 pm, "jim.renkel" <james.ren...@gmail.com> > wrote: > > > > > > > >>> My concern with this proposal is that it opens up denials of > > > service, > > > > > >>> not to twitter.com, but to "associated" sites such as twitpic, > or > > > my > > > > > >>> site twxlate, among others > > > > > > > >>> For example, Lance Armstrong is a heavy user of twitpic. It is > very > > > > > >>> easy for anyone to find Lance's twitter ID (@lancearmstrong), > view > > > his > > > > > >>> status updates, and see that he is a frequent user of twitpic. > Now, > > > > > >>> someone that is "unhappy" with Lance, say one of George > Hincapie's > > > > > >>> ardent fans that really believes that Lance was a significant > > > > > >>> contributor to George not winning the maillot jeune last > Sunday, > > > > > >>> could go to twitpic, fail to login as Lance the requisite > number of > > > > > >>> times, and deny Lance access to twitpic. > > > > > > > >>> Not only celebrities would or could be subject to such denials > of > > > > > >>> service. I notice that @dougw occasionally uses twitpic! :-) > > > > > > > >>> One solution to this problem is to add to each twitter account > > > another > > > > > >>> "private" ID. By default this private ID would be equal to the > > > > > >>> existing (public) ID (If not equal to the account's public ID, > it > > > > > >>> would have to be unique among all twitter IDs, both public and > > > > > >>> private.). > > > > > > > >>> The public ID would be used just as the existing twitter ID is > now: > > > > > >>> others would use it to follow, mention, DM, etc., the user. > > > > > > > >>> But the user MUST use their private ID for authenticated > requests > > > > > >>> through the API, and CAN also use it for non-authenticated > > > requests. > > > > > >>> In either case, twitter would treat a request from a private ID > as > > > if > > > > > >>> it came from the corresponding public ID. > > > > > > > >>> Blocking the public ID because of excessive authentication > failures > > > > > >>> would NOT block the associated private ID unless they were > equal. > > > > > >>> Changing your public ID would also change your private ID if > the > > > two > > > > > >>> were the same before the change, i.e., they would remain the > same > > > > > >>> after the change. > > > > > > > >>> It may seem onerous to require all users to also have a private > ID, > > > > > >>> but since it defaults to be the same as their public ID, only > those > > > > > >>> concerned about their service being denied would change it and > > > > > >>> subsequently use it instead of their public ID to access > associated > > > > > >>> sites such as twitpic or twxlate. > > > > > > > >>> In fact, I think this change, though potentially large on the > > > twitter > > > > > >>> side, could be implemented without any changes to users or > > > associated > > > > > >>> sites, with one small, obscure exception: now, if I attempt to > > > create > > > > > >>> a new twitter account or change the ID of an existing account, > and > > > > > >>> find that the ID I want is in use, I can view that account; if > this > > > > > >>> were implemented and I attempted to use a private ID that was > not > > > the > > > > > >>> same as its associated public ID, I could not view the account > > > using > > > > > >>> the denied ID. > > > > > > > >>> Comments expected and welcome. > > > > > > > >>> Jim Renkel > > > > > > > >>> On Jul 21, 6:00 pm, Doug Williams <d...@twitter.com> wrote: > > > > > > > >>>> Devs --A change shipped last week that limited the number of > times > > > a > > > > > >>>> user > > > > > >>>> could access the account/verify_credentials method [1] in a > given > > > hour. > > > > > >>>> This > > > > > >>>> change proved hasty and short-sighted as pointed out by the > > > subsequent > > > > > >>>> discussion [2]. We apologize to any developer that was > adversely > > > > > >>>> affected. Given the problems, we want to fix this in a > > > > > >>>> public and transparent manner. > > > > > >>>> Like most web services, we limit the number of attempts users > can > > > make > > > > > >>>> to > > > > > >>>> login to > > > > > >>>> their accounts on Twitter.com to prevent brute force > dictionary > > > > > >>>> attacks. This same security is not extended to the platform > > > > > >>>> and leaves accounts vulnerable to the same method of attack > > > through the > > > > > >>>> API. > > > > > >>>> The change we shipped to limit user accounts to 15 calls > an > > > hour to > > > > > >>>> the > > > > > >>>> account/verify_credentials method [1] was intended to mitigate > > > this > > > > > >>>> risk. It > > > > > >>>> was thought to limit the number of tests a potential attack > could > > > run in > > > > > >>>> the > > > > > >>>> hour, even in a distributed fashion. However, we only > protected a > > > single > > > > > >>>> resource which still leaves all other authenticated methods > > > exposed as a > > > > > >>>> vector of attack (limited only by the API rate limit). > > > > > >>>> Our thinking is now that we will limit the total number > of > > > > > >>>> unsuccessful > > > > > >>>> attempts to access authenticated resources to 15 an hour per > user > > > per IP > > > > > >>>> address. If a single IP address makes 15 attempts to access a > > > protected > > > > > >>>> resource unsuccessfully for a given user (as indicated by an > HTTP > > > 401), > > > > > >>>> then > > > > > >>>> the user will be locked out of authenticated resources from > that > > > IP > > > > > >>>> address > > > > > >>>> for 1 hour. > > > > > >>>> This scheme has all of the positive effects that we need, > > > however > > > > > >>>> we want to > > > > > >>>> make sure that we have thought through all of the potential > > > problems on > > > > > >>>> the > > > > > >>>> developer's side before we proceed with this change. Please > > > contribute > > > > > >>>> to > > > > > >>>> the subsequent discussion if you have an opinion or concern. > Once > > > we > > > > > >>>> come to > > > > > >>>> an agreement, we will update with details and a timeline for > > > shipping > > > > > >>>> this > > > > > >>>> update. > > > > > > > >>>> 1. > > >http://apiwiki.twitter.com/Twitter-REST-API-Method%3A-account%C2%A0ve. > .. > > > > > > > >>>> 2. > > > > ... > > > > read more ยป >
