对于我正在从事的一个新的node.js项目,我正在考虑从基于cookie的会话方法(我的意思是,将id存储到用户浏览器中包含用户会话的键值存储中)切换到使用JSON Web Tokens (jwt)的基于令牌的会话方法(没有键值存储)。

这个项目是一个利用socket的游戏。IO——在一个会话(web和socket.io)中有多个通信通道的情况下,有一个基于令牌的会话会很有用。

如何使用jwt方法从服务器提供令牌/会话失效?

我还想了解使用这种范例应该注意哪些常见的(或不常见的)陷阱/攻击。例如,如果这种模式容易受到与基于会话存储/cookie的方法相同/不同类型的攻击。

所以,假设我有以下内容(改编自this和this):

会话存储登录:

app.get('/login', function(request, response) {
    var user = {username: request.body.username, password: request.body.password };
    // Validate somehow
    validate(user, function(isValid, profile) {
        // Create session token
        var token= createSessionToken();

        // Add to a key-value database
        KeyValueStore.add({token: {userid: profile.id, expiresInMinutes: 60}});

        // The client should save this session token in a cookie
        response.json({sessionToken: token});
    });
}

口令登录:

var jwt = require('jsonwebtoken');
app.get('/login', function(request, response) {
    var user = {username: request.body.username, password: request.body.password };
    // Validate somehow
    validate(user, function(isValid, profile) {
        var token = jwt.sign(profile, 'My Super Secret', {expiresInMinutes: 60});
        response.json({token: token});
    });
}

--

会话存储方法的注销(或失效)需要更新KeyValueStore 使用指定的令牌创建数据库。

在基于令牌的方法中似乎不存在这样的机制,因为令牌本身将包含通常存在于键值存储中的信息。


当前回答

没有使用jwt的刷新…

我想到了两种袭击的场景。一个是关于登录凭证的泄露。另一个是对JWT的盗窃。

For compromised login credentials, when a new login happens, normally send the user an email notification. So, if the customer doesn't consent to being the one who logged in, they should be advised to do a reset of credentials, which should save to database/cache the date-time the password was last set (and set this too when user sets password during initial registration). Whenever a user action is being authorized, the date-time a user changed their password should be fetched from database/cache and compared to the date-time a given JWT was generated, and forbid the action for JWTs that were generated before the said date-time of credentials reset, hence essentially rendering such JWTs useless. That means save the date-time of generation of a JWT as a claim in the JWT itself. In ASP.NET Core, a policy/requirement can be used to do do this comparison, and on failure, the client is forbidden. This consequently logs out the user on the backend, globally, whenever a reset of credentials is done.

For actual theft of JWT... A theft of JWT is not easy to detect but a JWT that expires easily solves this. But what can be done to stop the attacker before the JWT expires? It is with an actual global logout. It is similar to what was described above for credentials reset. For this, normally save on database/cache the date-time a user initiated a global logout, and on authorizing a user action, get it and compare it to the date-time of generation of a given JWT too, and forbid the action for JWTs that were generated before the said date-time of global logout, hence essentially rendering such JWTs useless. This can be done using a policy/requirement in ASP.NET Core, as previously described.

现在,你如何发现JWT被盗?目前我对此的回答是,偶尔提醒用户全局注销并重新登录,因为这肯定会让攻击者注销。

其他回答

在内存中做一个这样的列表

user_id   revoke_tokens_issued_before
-------------------------------------
123       2018-07-02T15:55:33
567       2018-07-01T12:34:21

如果您的令牌在一周内过期,则清除或忽略更早的记录。同时只保留每个用户的最新记录。 列表的大小取决于您保留令牌的时间以及用户撤销令牌的频率。 仅当表发生变化时才使用db。在应用程序启动时将表加载到内存中。

Kafka消息队列和本地黑名单

我想过使用像kafka这样的消息系统。让我解释一下:

例如,您可以有一个微服务(我们称之为userMgmtMs服务),它负责登录和注销,并生成JWT令牌。然后将这个令牌传递给客户端。

现在客户端可以使用这个令牌来调用不同的微服务(让我们称之为pricesMs),在pricesMs中,将没有数据库检查用户表,从这个表中触发了最初的令牌创建。该数据库只能存在于userMgmtMs中。此外,JWT令牌应该包括权限/角色,这样pricesm就不需要从DB中查找任何东西来允许spring安全性工作。

JwtRequestFilter可以提供一个UserDetails对象,该对象由JWT令牌中提供的数据创建(显然没有密码),而不是去到pricesMs中的DB。

那么,如何注销或使令牌失效呢?由于我们不想在每次请求priecesm时都调用userMgmtMs的数据库(这会引入很多不必要的依赖关系),因此解决方案可以使用这个令牌黑名单。

我建议使用kafka消息队列,而不是保持这个黑名单集中,并依赖于所有微服务的一个表。

userMgmtMs仍然负责注销,一旦注销完成,它就会把它放入自己的黑名单(一个微服务之间不共享的表)。此外,它还将带有此令牌内容的kafka事件发送到订阅了所有其他微服务的内部kafka服务。

一旦其他微服务接收到kafka事件,它们也会将其放入内部黑名单。

即使一些微服务在注销时关闭了,它们最终也会重新启动,并在稍后的状态下接收消息。

由于kafka是这样开发的,客户端有他们自己的引用,他们读了哪些消息,确保没有客户端,down或up将错过任何这些无效的令牌。

The only issue again what I can think of is that the kafka messaging service will again introduce a single point of failure. But it is kind of reversed because if we have one global table where all invalid JWT tokens are saved and this db or micro service is down nothing works. With the kafka approach + client side deletion of JWT tokens for a normal user logout a downtime of kafka would in most cases not even be noticeable. Since the black lists are distributed among all microservies as an internal copy.

在关闭的情况下,你需要使一个被黑客攻击的用户无效,kafka宕机了,这就是问题开始的地方。在这种情况下,作为最后的手段改变秘密可能会有所帮助。或者在这样做之前确保卡夫卡已经起床了。

免责声明:我还没有实现这个解决方案,但不知怎么的,我觉得大多数提议的解决方案都否定了JWT令牌的想法,因为它有一个中央数据库查找。所以我在考虑另一种解决方案。

请让我知道你的想法,它是有意义的还是有一个明显的原因为什么它不能?

我要回答的是,当我们使用JWT时,我们是否需要提供从所有设备注销功能。这种方法将对每个请求使用数据库查找。因为即使服务器崩溃,我们也需要持久安全状态。在用户表中,我们将有两列

LastValidTime(默认为创建时间) 登录(默认值:true)

每当有来自用户的注销请求时,我们将LastValidTime更新为当前时间,login - in更新为false。如果有一个登录请求,我们不会改变LastValidTime,但登录将被设置为true。

当我们创建JWT时,我们将在有效载荷中有JWT创建时间。当我们授权一项服务时,我们将检查3个条件

JWT有效吗 JWT有效负载创建时间是否大于用户LastValidTime 用户是否已登录

让我们来看一个实际的场景。

用户X有两个设备A和b,他在晚上7点使用设备A和设备b登录到我们的服务器(假设JWT过期时间是12小时)。A和B都有JWT, createdTime: 7pm

在晚上9点,他丢失了他的设备b,他立即从设备a注销。这意味着现在我们的数据库X用户条目的LastValidTime为“ThatDate:9:00:xx:xxx”,登录为“false”。

在9:30,Mr.Thief尝试使用设备b登录,我们将检查数据库,即使登录是假的,所以我们不允许。

晚上10点,x先生从他的设备A登录,现在设备A有JWT,并创建了时间:10点。现在database Logged-In被设置为true

晚上10点半,小偷先生试图登录。即使“登录”是真的。数据库中的LastValidTime是晚上9点,但是B的JWT创建的时间是晚上7点。所以他不会被允许访问该服务。所以使用设备B没有密码,他不能使用已经创建的JWT在一个设备注销后。

如果您希望能够撤销用户令牌,您可以跟踪DB上所有发出的令牌,并检查它们在类似会话的表上是否有效(存在)。 缺点是每次请求都要访问DB。

我还没有尝试过,但我建议使用以下方法来允许令牌撤销,同时将DB命中保持在最小值-

为了降低数据库检查率,根据某种确定性关联将所有已发行的JWT令牌分成X组(例如,按用户id的第一个数字分为10组)。

每个JWT令牌将保存组id和令牌创建时创建的时间戳。例如,{"group_id": 1, "timestamp": 1551861473716}

服务器将在内存中保存所有组id,每个组都有一个时间戳,该时间戳指示属于该组的用户的最后一次注销事件是什么时候。 例如,{"group1": 1551861473714, "group2": 1551861487293,…}

使用带有较旧组时间戳的JWT令牌的请求将被检查是否有效(DB hit),如果有效,将发出一个带有新时间戳的新JWT令牌供客户端将来使用。 如果令牌的组时间戳较新,则相信JWT (No DB hit)。

So -

We only validate a JWT token using the DB if the token has an old group timestamp, while future requests won't get validated until someone in the user's group will log-out. We use groups to limit the number of timestamp changes (say there's a user logging in and out like there's no tomorrow - will only affect limited number of users instead of everyone) We limit the number of groups to limit the amount of timestamps held in memory Invalidating a token is a breeze - just remove it from the session table and generate a new timestamp for the user's group.

没有使用jwt的刷新…

我想到了两种袭击的场景。一个是关于登录凭证的泄露。另一个是对JWT的盗窃。

For compromised login credentials, when a new login happens, normally send the user an email notification. So, if the customer doesn't consent to being the one who logged in, they should be advised to do a reset of credentials, which should save to database/cache the date-time the password was last set (and set this too when user sets password during initial registration). Whenever a user action is being authorized, the date-time a user changed their password should be fetched from database/cache and compared to the date-time a given JWT was generated, and forbid the action for JWTs that were generated before the said date-time of credentials reset, hence essentially rendering such JWTs useless. That means save the date-time of generation of a JWT as a claim in the JWT itself. In ASP.NET Core, a policy/requirement can be used to do do this comparison, and on failure, the client is forbidden. This consequently logs out the user on the backend, globally, whenever a reset of credentials is done.

For actual theft of JWT... A theft of JWT is not easy to detect but a JWT that expires easily solves this. But what can be done to stop the attacker before the JWT expires? It is with an actual global logout. It is similar to what was described above for credentials reset. For this, normally save on database/cache the date-time a user initiated a global logout, and on authorizing a user action, get it and compare it to the date-time of generation of a given JWT too, and forbid the action for JWTs that were generated before the said date-time of global logout, hence essentially rendering such JWTs useless. This can be done using a policy/requirement in ASP.NET Core, as previously described.

现在,你如何发现JWT被盗?目前我对此的回答是,偶尔提醒用户全局注销并重新登录,因为这肯定会让攻击者注销。