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

I ended up with access-refresh tokens, where refresh tokens uuids stored in database and access tokens uuids stored in cache server as a whitelist of valid access tokens. For example, I have critical changes in user data, for example, his access rights, next thing I do - I remove his access token from cache server whitelist and by the next access to any resource of my api, auth service will be asked for token's validity, then, if it isn't present in cache server whitelist, I will reject user's access token and force him to reauthorize by refresh token. If I want to drop user's session or all of his sessions, I simply drop all his tokens from whitelist and remove refresh tokens from database, so he musts re-enter credentials to continue accessing resources.

我知道,我的身份验证不再是无状态的,但公平地说,我为什么还要无状态的身份验证呢?

其他回答

如果“注销所有设备”选项是可接受的(在大多数情况下是):

将令牌版本字段添加到用户记录中。 将此字段中的值添加到存储在JWT中的声明中。 每次用户注销时增加版本。 在验证令牌时,将其版本声明与存储在用户记录中的版本进行比较,如果不相同则拒绝。

无论如何,在大多数情况下都需要db访问以获取用户记录,因此这不会给验证过程增加太多开销。与维护黑名单不同,在黑名单中,由于需要使用连接或单独调用、清除旧记录等,数据库负载非常重要。

为什么不直接使用jti声明(nonce)并将其作为用户记录字段存储在列表中(依赖于db,但至少是逗号分隔的列表)?不需要单独查找,正如其他人指出的那样,假设您无论如何都想获得用户记录,这样您就可以为不同的客户端实例拥有多个有效的令牌(“到处注销”可以将列表重置为空)

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。

我一直在考虑的一种方法是在JWT中始终有一个iat(发布时间)值。然后,当用户注销时,将时间戳存储在用户记录上。在验证JWT时,只需将iat与上次注销的时间戳进行比较。如果iat更老,那么它是无效的。是的,您必须访问DB,但如果JWT在其他方面有效,我将始终提取用户记录。

我所看到的主要缺点是,如果他们在多个浏览器中,或者有一个移动客户端,它会让他们退出所有的会话。

这也是一种很好的机制,可以使系统中的所有jwt无效。部分检查可以针对最后有效的iat时间的全局时间戳。

即使从存储中删除令牌,它仍然有效,但只是在短时间内有效,以降低它被恶意使用的可能性。

您可以创建一个拒绝列表,一旦从存储中删除令牌,就可以将令牌添加到该列表中。如果你有一个微服务,所有其他使用这个令牌的服务都必须添加额外的逻辑来检查这个列表。这将集中您的身份验证,因为每个服务器都必须检查一个集中的数据结构。