I don't like the idea that all data between the client and server is raw json text, it is making it to easy for about any script kiddie to understand the requests and then to tamper with the json values to see if he gets lucky.
Even there is no way to hide a secret salt in javascript, i have still thought about making an algorithm to generate salts in both ends (Client/VueJS/javascript and then in c#/server) that would auto generate the same salt in both sides. And throw in some random data like timestamp etc to change the salt on a regular basis.
I figure what I would achieve by this is that the requests at least would appear less obvious at first glance.
Does it exist a good/better way to encrypt the payloads between vueJs and a API server?
Updated:
I should have foreseen some obvious comments on this question. I will clean a few things out of the way:
Users are authenticated, and the server does not give the user access to do more than what its ment to give them.
Here is the context to consider:
You do not even trust users with administrator roles, this is users who have rights to do some real damage. What would you do to prevent this "super users" from misusing your API?
Does it exist a good/better way to encrypt the payloads between vueJs and a API server?
No, that's impossible.
Encryption relies on having a secret key that is used to encrypt and decrypt the payload. Any application running in the browser (JavaScript, WASM, or otherwise) delivers its source code to the browser so it can execute, which means your attackers have access to it.
If your JavaScript code generates a key in memory, that memory can be read by the browser user at any time.
Even if you rely on obfuscation, that's not good enough. You can try to be as clever as you want, someone is going to reverse engineer the jumbled up code you publish.
Don't ever trust data provided by the client. Always authenticate and authorize your API calls.
I would argue that this approach is very close to the infamous security through obscurity approach and in general not worth the effort. You client code is obviously is available to clients and this will not prevent malicious user from figuring this trick out and replicating it. I think it is much better to spend time on security testing and implementing techniques to prevent at least most common vulnerabilities (for example).
Forgive me if this is a stupid and obvious question, but I'm having trouble googling for the correct resources. I'm not a security expert and I'm struggling to understand how to properly go about this.
Here's the scenario. I have an internal application on an internal server: not something that will ever go out to a client site. This application has a database of username and password pairs that are used to talk to secure web services. I have no need to keep these passwords secret from colleagues, but I want to protect them in case the server is attacked and the data stolen.
Traditionally one would salt and hash them. This is a process I understand in principle but it depends on the user entering a password which can then be validated against the stored hash. That's not the case for me.
So: searching around there are various solutions that use a fixed "pass phrase" to secure a string. Here's a one example, https://stackoverflow.com/a/10177020/271907 and here is another https://stackoverflow.com/a/10366194/188474.
However, as I understand it neither of these offers a useful solution in my case. That "pass phrase" is going to have to be stored somewhere for my application to do its work. If I hard-code it into the application it can be reverse engineered. If I encrypt it and put it in a separate file it can be stolen and worked out using a rainbow table.
I looked into using reg_iis to encrypt a key as per Encrypting Web Config using ASPNET_REGIIS but, to be honest, that just left me even more confused. I'm not even sure whether or not these encrypted config files can be ported between machines or whether I'd have to re-encrypt between dev and test and live. I don't know how secure they are either: AFAIK there has to be a key somewhere and if there's a key it can be broken.
To further muddy the waters I found this answer which doesn't use a key: https://stackoverflow.com/a/10176980/271907. However the author admits it's out of date and I have no idea how secure the result is.
Is there any kind of sensible approach to solving this problem that doesn't leave a hole in the security somewhere?
Any solution where you decrypt the password to check it is going to fundamentally be insecure because your application must always know how to do that decryption.
You can make it harder by not storing the decryption key in the code, but wherever you put it a hacker that can compromise your code can probably access anything it can access too.
Even if your application security is rock solid; your passwords are still plain text in your DB and if that gets compromised then lots of your users are exposed.
That said - this is an internal-only, low risk system. Your best course of action may be to let your bosses know the relative risk vs the cost of proper security and let them make an explicit business call (and carry any future blame).
The only way of doing this without leaving a hole in the security is by hashing and salting the passwords with a one-way algorithm. The fact that current passwords are plain text shouldn't be a problem - there are lots of ways to push users to encrypt them, but easiest is just to do it for them: next time they log in, if they have a plain text password encrypt it. Then after a suitable wait (depending how often your users log in) remove the old password and check against the new hash.
The golden rule is: if you store passwords you must hash them in a way you can't reverse
The only other option is for you to not authenticate at all - use NTLM or AD or OAuth to get some other service to authenticate the user and just trust that source instead.
If instead you're looking to secure the credentials the application uses itself then you have a similar problem, but the focus shifts. You still can't do much to avoid exposure if the host machine is compromised, but most attacks will only target files.
This can be a problem if all your connection details are held in a web.config or appsettings.json as compromising those files can expose your SQL server or other service passwords.
This is where you can use ASPNET_REGIIS - it lets you add secret configuration that IIS can access, but that isn't held in plain text with the web files.
In .NET core there's new Microsoft.Extensions.SecretManager.Tools that do the same thing.
Both of these add a layer of protection for any application credentials that would otherwise be stored in plain text on disk. Attackers must compromise the machine to get at them, rather than just the files.
In both cases these configuration details are no longer portable - you'll have to set them up again (and re-encrypt) on each server.
However, you only really need the additional protection in live - in development or testing sandboxes you can just use the plain text config, and then override the details with the encrypted settings on the live server.
Is it possible to safely include a password in a query string for a c# asp.net site.
Few assumptions and things I know -
The site does not and will not have links/images/javascript/analytics to/from other sites. So no referrer links to worry about.
ALL communication with the web browser will be over https.
I know that the query string will remain in the history of the
computer.
More than just the password/username is needed to login. So simply
pasting the url back into the browser will not result in a login.
I know the site may be susceptible to cross site scripting and replay attacks. How do I mitigate these?
Given the above scenario, how should I include a password in a query string?
Please don't ask me 'why', I know this is not a good idea, but it is what the client wants.
SSL
You can safely send the password to a web server using a SSL connection. This encrypts all the communication between the client/server.
Hide In The Header
Basic authentication protocols place the user/password information in the HTTP request header. C# and many other web server languages can access this information, and use it to authenticate the request. When mixed with SSL this is very safe.
Register An Application Key
If none of the above is possible, then it's recommended that you create a unique key for each user. Rather then send their password this key is used. The advantage is that the key is stored in the database and can be removed. The user's password remains unchanged, but they must register again to get a new key. This is good if there is a chance someone could abuse their key.
Perform Hand Shaking
Hand shaking is where the client makes a request to the server, and the server sends back a randomly generated key. The client then generates a hash from that key using a secret, and sends it back to the server. The server can then check if the client knew the correct secret. The same thing can be done where the password is the secret instead and the client includes username details in the request. This can authenticate without ever sending the password.
Encrypt Password
If none of the above are possible options, then you could attempt to use JavaScript to encrypt the password before it's sent via an open URL. I found an open source version the AES block cipher. The project is called JSAES and supports 128 to 256 bit encryption. There might be other JS libraries that do the same thing.
It is generally not advisable to put secrets in a query string, which can then be book marked and copied, exposing the password at-rest in history files, cookies, etc.
To just safeguard the password in this use-case, an option would be to hash the password (one-way, not reversible). In this way, the actual password is not known in transit nor at-rest but... it implies that an attacker can still use the hashed value to login to the server that would presumably compare the hash value to its store for authentication.
Update: Switching to stateless (JWT) sessions
In the olden days when buggies were a thing (okay - they are still a thing with some fringe groups but) - we used "sessions".
A "session-ID" (see JSESSION_ID) for example in Java/J2EE/Servlet based systems was stored as a cookie. That value, being a random number, was hard to guess - but it had problems from hijacking to memory and lookup overhead on the server.
In 2020 times (as of this writing) ... JSON Web Tokens (JWT) can be used to securely encapsulate the user-session information and be pushed back down in an immutable cookie without ever exposing the password and with very little server overhead.
In this model, after login, the server issues a token (using OAUTH2 or related), which has an expiration time-stamp.
This data and possibly other session information can then be encrypted, hashed, signed and wrapped up in a JWT (token) - as a cookie back to the web-browser.
Ref: https://oauth.net/2/jwt/
At this point, the client cannot do anything to compromise (or even view) the cookie because any sensitive data should have been encrypted (using AES256 et al or better) and the contents hashed and the hash signed. What this means is that when the server gets the token back, it looks at the timestamp and may throw it out - forcing re-authentication and then...
Can otherwise verify it signed the content, hash the contents and verify the hash and decrypt data if needed (which would not include the password but rather just the ID of the user - which is verified and not necessarily a secret per se).
This can include already-looked-up scopes (authorization) for what the user can do etc - avoiding round trips to the authentication server until the token times out.
Thus the above (using JWTs, hashing, signing, encrypting - into a cookie) is the recommended way to both go stateless and avoid passing around a secret between the client and server.
Ref: https://auth0.com/blog/stateless-auth-for-stateful-minds/
Additionally, consider that multi-factor authentication schemes (see Google authenticator) and related systems are a much stronger security posture (stealing password is not enough and the keys auto-rotate on external systems) but do require semi-frequent access to the rotating key system, which inhibits a smooth user experience to some extent.
Update: Multi-Factor auth by Google and others has gotten much better.
Older companies still use SMS one-time-passwords (OTP) ... which can be compromised by going to a wireless company store and claiming SIM card loss (given a known phone-number).
Google and other more advanced companies comparatively use rotating tokens that can be embedded in a smartphone app that then are used for many services.
Google even has push-notification where user just confirms by button press: "Yes - it is me".
I have an application which exposes service which is consumed by the web application via Jquery POST and other applications (IPad, Android, etc). I have to create an authentication system which is highly safe but still fast enough.
I thought of making a token which will be passed to the application on login and which will be used for a specific amount of time (say 30 mins) post which it should refresh itself and not expire the session. So I thought of making a token being sent to service and which will generate token. It will accept
UserId
Password (both encrypted with public key)
AppId
The server will decrypt the request by the private key and generate a token which will be valid for a specific time. Now since this would highly depend on the private key (which will be same and thus someone from within system can leak it and misuse it) so i want the private key to be refreshed after a specific time (say 2 hrs).
Question -
How do refresh Private key and ensure that the currently issues tokens will not be rejected.
Is there a better way of doing it
Is there a better way of doing it?
Yes there is, It's called SSL/HTTPS. If you are already using HTTPS then there is no need for any of this crypto-magic. If you are not using HTTPS you are already insecure by design and nothing you come up with will fix that short of re-inventing SSL.
So what should you do if the transport is secure (HTTPS)
Client makes a request for authentication sending username + password in plain-text.
Server verifies the username + password pair against the (hopefully) hashed password stored with the account.
Server responds with a token (encrypted account id, expiration, etc) using a static AES key.
Client uses the token for all authenticated requests.
Easy.
One thing you could do...
To prevent loss of credentials used on non-secure devices you should take a page from Google and others. Rather than having users entering their website passwords, make them visit and log in to your web server. From there they click a 'generate access token for device'. A unique data string (20 or more characters) is generated and recorded with their account. This 'alternate password' can then be revoked by the user from your website.
How can I make this more secure?
You really can't do much better, here is why...
Assume an attacker gains access to your private key. The attacker can then replace your server or play man-in-the-middle while stealing usernames and passwords.
To attempt to prevent this you contrive some PKI exchange to send the password encrypted by a public key the server gave you. I as a man-in-the-middle can simply give you my own public key and access the username and password and then if I choose, forward it to the real server.
--or--
To attempt to prevent this you use some salt + password hash that will be sent to the server in place of the password in clear text. I as a man-in-the-middle can simply give you a fixed value for the salt and then pre-compute a complete rainbow table for that salt value. Now I again have everyone's password (well most) in clear text.
--or--
To attempt to prevent this you use PKI to establish some secret session key and then sign and encrypt every communication. Well, gee... that sounds familiar... see SSL on Wikipedia. Realize that the ONLY thing that makes SSL secure is the protection of it's private keys. Once a private key is lost, all security and trust is lost.
Final notes:
Without being able to protect some encryption key you cannot build a secure communication.
You should also be aware that thousands of man hours have been spent on software implementations of SSL (like OpenSSL) and they constantly find vulnerabilities in their implementations. Your hope of implementing this yourself, and doing it as secure as IIS or OpenSSL, is almost NIL. That is not a Digg on you, that is just reality, I couldn't do it either I only know enough to not even try.
Lastly, my final advice is about your statement: "someone from within system can leak it and misuse it". This is your real problem. Fix that and all else will be much easier. Securing a server environment should be your first priority. Your second priority should be minimizing the impact to your customers once you fail to do the first.
Some helpful links:
How to generate password using a specific set of characters.
Another example of how to store a salted password hash.
I am using asp.net mvc 2.0 and I am wondering how secure is it to put information in a cookie?
Like I put in my cookie a forms authentication ticket that is encrypted so can I put information that could be sensitive in there?
string encryptedTicket = FormsAuthentication.Encrypt(authTicket)
HttpCookie authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);
Like I am not storing the password or anything like that but I want to store the UserId because currently every time the user makes a request to my site I have to do a query and get that users Userid, since every table in my db requires you to use the userId to get the right row back.
So these start to add up fast so I rather have it that if a user is authenticated once then that's it till they need to be re-authenticated again. If I would store this userId I could save so many requests to the database.
Yet I don't want it floating around in clear text as potential someone could use it to try to get a row out of a database when they really should not be.
Show how good is this encryption that Authentication uses?
The encryption is good enough, that's not the weak link.
The weak link is that the cookie value could be intercepted, and someone else could impersonate the user.
So, the information in the cookie is safe enough, but you can't protect the cookie itself.
The title of your question doesn't really match what you are asking. There are two different things you are asking here.
1. Is there a secure way to store data in a cookie?
The answer is yes. To safely store data in a cookie you have to encrypt the data you want to store then sign the encrypted data. Encrypting it prevents attackers from being able to read the data, signing it prevents attackers from modifying the data. This will ensure the integrity of the data. You could use this method to store data about the user you want to keep private (their email address, date of birth, etc). Note: Securely storing data in a cookie is not a safe way to authenticate a user! If you stored the user id of the user in the signed and encrypted cookie, nothing prevents an attacker from stealing the entire cookie and sending it back to the server. There's no way of knowing if the authentication cookie came from the same browser where the user entered their user name and password. Which leads us to the second question (the one you were actually asking)...
2. Is there a secure way to authenticate a user with a cookie?
Yes. To securely authenticate a user you must combine the techniques from question 1 with SSL (https). SSL ensures that only the browser will be able to access the authentication cookie (the signed encrypted cookie with the user id in it). This means that your login process (accepting the users name and password, as well as setting the authentication cookie) must happen over SSL. You must also set the HttpCookie.Secure property to true when you set the authentication cookie on the server. This tells the browser to only include this cookie when making requests to your website over SSL. You should also include an expiration time in the encrypted auth cookie to protect against someone forgetting to log out of your site while they are at the library. A side affect of this approach is that only pages on your site that are SSL will be able to authenticate the user. Which brings up a third question...
3. How do you securely authenticate a user without using SSL?
You don't. But you do have options. One strategy is to create two auth cookies at login, one regular cookie and one that is ssl-only (both encrypted and signed though). When performing sensitive operations on the users behalf, require the page be in SSL and use the SSL-only cookie. When doing non-sensitive operations (like browsing a store that is customized based on the country their account is in) you can use the regular auth cookie. Another option is to split the page so that information that requires knowing who the user is is retrieved async via AJAX or json. For example: You return the entire page of the blog over http and then you make an SSL AJAX request to get the current users name, email, profile pic, etc. We use both of these techniques on the website I work on.
I know this question was asked almost a year ago. I'm writing this for posterities sake. :-)
Along with cookie encryption, you should also implement a rotating token to prevent replay attacks.
The idea being that the encrypted cookie contains some value which can be compared to a known value on the server. If the data matches, then the request succeeds. If the data doesn't match then you are experiencing a replay attack and need to kill the session.
UPDATE
One of the comments asked if I meant to store the value in the cookie. The answer is yes. The ENTIRE cookie should be encrypted, which can be automatically done through the use of an HttpModule. Inside the encrypted cookie is any of your normal information + the changing token.
On each post back, check the token. If it's valid, allow the transaction, create a new random token, store in the cookie, and send that back to the browser. Again, in an encrypted form.
The result is that your cookie is secure (you are using 3DES?) and any attacker would have an extremely limited window of opportunity to even attempt a replay attack. If a token didn't pass muster, you could simply sound the alarm and take appropriate measures.
All that's needed server side is to keep track of the user and their current token. Which is usually a much smaller db hit than having to look up little things like the users name on each page load.
UPDATE 2
I've been trying to figure out whether this is better or worse than keeping the changing value stored in session. The conclusion I've come to is that storing a rotating value in session on the web server does absolutely nothing to prevent replay attacks and is therefore less secure than putting that value in a cookie.
Consider this scenario. Browser makes request. Server looks at the session id and pulls up the session objects, work is then performed, and the response is sent back to the browser. In the meantime, BlackHat Bob recorded the transaction.
Bob then sends the exact same request (including session id) to the server. At this point there is absolutely no way for the server to know that this is a request from an attacker. You can't use IP as those might change due to proxy use, you can't use browser fingerprinting as all of that information would have been recorded in the initial exchange. Also, given that sessions are usually good for at least 30 minutes and sometimes much longer, the attacker has a pretty good sized window to work in.
So, no matter what, to prevent replay you have to send a changing token to the browser after each request.
Now this leaves us with the question about whether to also store values such as the user id in an encrypted cookie or store it server side in a session variable. With session you have concerns such as higher memory and cpu utilization as well as potential issues with load balancing etc. With cookies you have some amount of data that is less than 4kb, and, properly done, in the 1kb or less range that gets added to each request. I guess it will boil down to whether you would rather add more / larger servers and internal networking equipment to handle the requests (session) or pay for a slightly larger internet pipe (cookie).
As you've stated, a good practice for storing any data in cookies is to encrypt the data. Encrypt before putting into the cookie, and decrypt after reading it.
In the example of storing a user identifier, choose something that's not likely to be used against your system. For the user id, use a guid rather than the likely incrementing integer that's the PK on the database table. The guid won't be easily changed to successfully guess another user during an attack on your system.
Once the user has been identified or authenticated, go ahead and store the user object, or key properties in Session.
In an ideal world with an ideal cipher this wouldn't be a problem. Unfortunately in the real world nothing is ideal, and there never will be an ideal cipher. Security is about solving these real world threats. Cryptographic systems are always vulnerable to attack, weather it be a trivial(brute force) attack or by a flaw in the primitive its self. Further more it is most likely that you will botch the implementation of the primitive, common mistakes include non-random or null IV, Key management, and incorrect block Cipher mode.
In short this is a gross misuse of cryptography. This problem is best sovled by avoiding it all together by using a session variable. This is why sessions exist, The whole point is to link a browser to state data stored on the server.
edit: Encrypting cookies has led to the ASP.NET oracle padding attack. This should have been avoided all together by using a Cryptographic Nonce. Like i said, this is a gross misuse of cryptography.
For your very specific scenario (user id), the short answer is NO!
For the long answer, imagine this hypothetical scenario:
You navigate to stackoverflow.com;
Fill your username/password and submit the form;
The server sends you a cookie containing your user ID, which is going to be used to identify you on the next requests;
Since your connection was NOT secure (HTTPS), a bad guy sniffed it, and captured the cookie.
The bad guy gains access to your account because the server didn't store, let's say, your IP address, and thus, can't distinguish between your machine and the bad guy's.
Still in this scenario, imagine the server stored your IP address, but you're on a corporate LAN, and your external IP is the same of another 100 machines. Imagine that someone that has access to one of these machines copied your cookie. You already got it, right? :-)
My advice is: put sensitive information on a HTTP session.
UPDATE: having a session implies a cookie (or at least an ugly URL), thus leading us back to the very same problem: it can be captured. The only way to avoid that is adding end-to-end encryption: HTTP+SSL = HTTPS.
And if someone says "oh, but cookies/sessions should be enough to discourage most people", check out Firesheep.
It's okay (not great, but not wrong) from a security standpoint. From a performance standpoint, however, it's something you want to avoid.
All cookies are transmitted from client to server on every request. Most users may have fast broadband connections these days, but those connections are asymetric — the upstream bandwidth used for transmitting cookie data is often still very limited. If you put too much information in your cookies, it can make your site appear sluggish, even if your web server is performing with capacity to spare. It can also push your bandwidth bill up. These are points that won't show up in your testing, which most likely happens all on your corporate network where upstream bandwidth from client to server is plentiful.
A better (general) approach is to just keep a separate token in the cookie that you use as a key to a database lookup for the information. Database calls are also relatively slow (compared to having the information already in memory or in the request), but primary key lookups like this aren't bad and it's still better then sending the data potentially a quarter of the way around the world on every request. This is better for security as well, because it keeps the data off the user's machine and off the wire as much as possible. This token should not be something like the userid from your question, but rather something more short-lived — a key used to index and hide away larger blocks of data, of which your userid is perhaps one part.
For your userID, which is likely only a single integer, as well as other small and important data, keep it in memory on the web server. Put it in the session.
The use you are looking at is the exact intended purpose of being able to store information in the Forms Auth Ticket.
No. It have been shown with Padding oracle attack that receiving encrypt data (CBC) can be dangerous because of the errors leakage.
I'm definitely not a crypto expert but I recently saw a demo where encrypted view-state was decrypt using this attack.
Encrypting the userid value in the cookie only prevents the user from knowing what the value is. It does not
prevent cookie replay (use SSL to
prevent an attacker from intercepting
a victim's cookie)
prevent tampering
(an attacker can still blindly flip
bits in the encoded cookie with a
chance that it will decode to a valid
userid, use an HMAC to prevent this)
completely prevent a user from getting the decrypted value (the user can brute force the value off line, use a strong encryption key to make success less probable)
Encrypting the cookie also introduces a key management problem. For example, when you rotate the encryption key you have to make sure "live" sessions with the old key won't immediately fail. You thought about managing the encryption key, right? What happens when admins leave? It's compromised? etc.
Does your architecture (load balancers, server distribution, ...) preclude using server-side session objects to track this information? If not, tie the userid to the session object and leave the "sensitive" data on the server -- the user only needs to have a session cookie.
A session object would probably be a lot easier and more secure for your stated concern.
To ensure proper auth cookie protection, you should make sure that you specify a secure encryption/hashing scheme (usually in the web.config) by setting the machineKey validation="SHA1" property (I use SHA1 but you can replace that with a different provider if desired). Then, make sure that your forms auth has the protection="All" attribute set so that the cookie is both hashed AND encrypted. Non-repudiation and data security, all in one :)
ASP.NET will handle encrypting/decrypting [EDIT: only the auth cookie!] the cookie for you, although for custom cookies you can use the FormsAuthentication.Encrypt(...) method, so just make sure that you're not sending the UserId via other cleartext means like the querystring.
HttpCookie c;
c.Secure = true;
Obviously this only works when transmitting via SSL, but this setting tells the browser not to send the cookie unless the connection is SSL, thus preventing interception via man-in-the-middle attacks. If you are not using a secure connection, the data in the cookie is totally visible to anyone passively sniffing the connection. This is, incidentally, not as unlikely as you'd think, considering the popularity of public wifi.
The first thing to address is whether the connections involved are secure. If they are not, assume the cookie or anything else between you and the client will be intercepted.
A cookie can be a liability once it is on the client machine. Review cookie theft, cross-site request forgery, confused deputy problem.
Cookies limitations: size, may be disabled and security risk(tampering). Of course if you encrypt cookie, there could be a performance hit. Session and Viewstate would be good alternative.
If you want it to be stored at client side, viewstate would be better. You can encrypt the string userid and store in viewstate. Session would be best option.
If your database calls are slow, consider caching
Viewstate