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

在本例中,我假设最终用户也有一个帐户。如果不是这样,那么其他的方法也不太可能奏效。

创建JWT时,将其持久化到数据库中,并与正在登录的帐户相关联。这意味着您可以从JWT中提取关于用户的其他信息,因此根据环境的不同,这可能是可行的,也可能是不可行的。

对于之后的每个请求,不仅要执行您所使用的框架附带的标准验证(我希望)(验证JWT是否有效),还包括用户ID或另一个令牌(需要与数据库中的令牌匹配)之类的东西。

注销时,删除cookie(如果使用),并从数据库中使JWT(字符串)无效。如果不能从客户端删除cookie,那么至少注销过程将确保令牌被销毁。

我发现这种方法,加上另一个唯一标识符(数据库中有2个持久化项,可用于前端),会话具有很强的弹性

其他回答

我会在用户模型上保存jwt版本号的记录。新的jwt令牌将其版本设置为此。

在验证jwt时,只需检查它的版本号是否等于用户当前的jwt版本。

任何时候你想要让旧的jwt失效,只要改变用户的jwt版本号。

If you are using axios or a similar promise-based http request lib you can simply destroy token on the front-end inside the .then() part. It will be launched in the response .then() part after user executes this function (result code from the server endpoint must be ok, 200). After user clicks this route while searching for data, if database field user_enabled is false it will trigger destroying token and user will immediately be logged-off and stopped from accessing protected routes/pages. We don't have to await for token to expire while user is permanently logged on.

function searchForData() {   // front-end js function, user searches for the data
    // protected route, token that is sent along http request for verification
    var validToken = 'Bearer ' + whereYouStoredToken; // token stored in the browser 

    // route will trigger destroying token when user clicks and executes this func
    axios.post('/my-data', {headers: {'Authorization': validToken}})
     .then((response) => {
   // If Admin set user_enabled in the db as false, we destroy token in the browser localStorage
       if (response.data.user_enabled === false) {  // user_enabled is field in the db
           window.localStorage.clear();  // we destroy token and other credentials
       }  
    });
     .catch((e) => {
       console.log(e);
    });
}

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。

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?

另一种选择是为关键的API端点提供一个中间件脚本。 如果管理员使令牌失效,此中间件脚本将检入数据库。 这种解决方案可能适用于不需要立即完全阻止用户访问的情况。