Authentication - establishing the authenticity of a person or other entity. Not to be confused with authorization - defining access rights to resources.

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Authentication with an untrusted server

I asked a related question earlier, but I want to ask a broader version this time: To simplify things let's say I've developed an application that allows users to send messages in a chat room, and to ...
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2answers
79 views

Are there any flaws in my design for a paper-based OTP grid?

I'm trying to implement two-factor authentication on the cheap for a website of mine. My bank uses this sort of grid-based OTP system, so I wanted to emulate it in my application: Cards are ...
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2answers
185 views

Security issues in “Remember Me” function code example

I'm a beginner, and these may be very obvious for you, but I'm trying to understand if there are security issues with this example. Today on Stack Overflow, I saw the following post: PHP Sessions ...
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82 views

Should Javascript & IFrames be used to refresh sessions when Master Cookie Domains are used?

Suppose I have 3 sites that I want to have SSO in, site1.com, site2.com, and auth.com. SSL is always required. According to how SiteMinder cookies are described here, one of those domains would ...
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3answers
139 views

“Remember me” cookies - did I implement them securely?

I am currently working on a pet project website and I want to implement the "remember me" feature for logins and wanted to know if my procedure is secure. The authentication process basically goes ...
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5answers
204 views

Why after a website password reset am I asked to login again?

I have noticed that every web site has the exact same behavior for their password reset pages. They send a link to your email using which you can reach the password reset page. On that page you enter ...
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2answers
116 views

Are AWS security groups sufficient to authenticate communication between instances? (HIPAA)

Say I have a private service that exposes sensitive information (PHI) via a REST API, and that I want to permit access to it from only one other service. Is it enough to partition these services ...
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2answers
254 views

Native app, token authentication without login/password

I'm working on a always online mobile game (native android/iOS app with Unity) and i would like to be able to authenticate the player without requiring any login/password at the beginning. For those ...
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0answers
89 views

Secure login procedure

I have implemented a login, and session, procedure for a web app and I am wondering whether what I have implemented is secure enough. The authentication is based on login password on https. If the ...
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1answer
52 views

Basis Authentication Protocol: a concrete attack

Below is an informal protocol narration of a simple authentication protocol. A sends to B a signed hash of message M, B's name and a nonce N. B knows that the message M is intended for him, that it ...
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3answers
108 views

Would this authentication method prevent MiTMs getting the password?

Assuming SSL/TLS cannot be used in this context, is this method secure enough to authenticate someone without someone listening to be able to retrieve the password from the information transmitted. ...
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2answers
115 views

Securing fingerprint templates stored on web authentication server

I have a multi-factor web authentication server, that in addition to regular passwords uses fingerprints for user authentication. Can anyone think of a security flaw in the following scenario: I ...
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2answers
109 views

Is a Windows AD credential combined with AD group membership 2 factor authentication?

We have a requirement for 2-factor authentication for our internal WiFi SSID's. Currently we use PEAP w/ MS-CHAPv2 to pass windows creds through the AP to a RADIUS server (A Domain Controller running ...
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3answers
118 views

User Account Guessing [duplicate]

I'm doing some research on user account guessing, and wanted to ask a question about some "bad practices". My thought is generally this is a trade-off between great user functionality/UX and ...
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1answer
60 views

Secure automatic authentication to samba share

I need to pull some data from network storage to a publicly available laptop that is running Linux. The network storage used to be provided via a server that could be connected to via ssh, but it has ...
4
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1answer
706 views

Compromised JSON Web Token (JWT) Bearer Token

We are implementing a REST service that requires authentication and authorization. Because of the stateless nature of REST API's, we want to use JWT to make authenticated calls to the API through a ...
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1answer
206 views

Server + Client certificate vs Server certificate + Client password

There are three different ways how TLS (1.2) can be used: server and client authenticate, only the server authenticates or neither authenticates. If neither server nor client authenticates using a ...
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2answers
220 views

How can LastPass enforce 2-factor authentication

I've recently started using LastPass and one of the things you can set as a policy for you password vault is Prevent offline access when using Google Authenticator. The local cache can be ...
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1answer
94 views

Auth / Login token schema

According to this answer, a valid login token schema would consist of the username (U) the time of issuance (T) and secret key K owned by the server only The suggestion then is to concatenate the ...
43
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1answer
4k views

How does a SIM card prevent cloning?

I have read a few articles about SIM cards, stating that the chip inside them uses some cryptographic magic to prevent people from cloning your number. This to me seems borderline impossible, given ...
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1answer
53 views

Better way to store user authentication on phone app

We are creating an app and registration of user happens in following way. User sends via app: email-id/phone and username. Server sends a pin to enter in app via phone/email. User enters the pin in ...
3
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3answers
662 views

Websites Forcing Weak Password Standards (Updated) [duplicate]

Please Note: I am not going to name the websites which have these horrible standards for their clients and users. I have had to change my passwords for my routine update just recently in the last ...
6
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2answers
912 views

Security concept for Android app with PHP based REST API

I'm trying to build my own PHP based REST Api for my Android app and I'm a litte bit confused by all the different user authentication stuff one can find on the internet. So I want to present my ...
6
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1answer
96 views

4 bytes authentication problem

I have a classic security problem where Alice needs to prove its identity to Bob but with quite unusual requirements and constraints due to a M2M context. EDITs in bold The communication channel ...
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3answers
161 views

What are the (practical) dangers of writing your own login method?

I have always been told that writing your own login method (e.g. validate user given the username and password) is bad practice, and that one should reuse existing libraries for that. I have always ...
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1answer
291 views

security in banking app with 4 digit pin code and social security number

The new banking app (for norwegian bank Gjensidige bank) for my android handset allows me to log in using only my social security number, and a 4 digit pin code. The social security number in norway ...
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3answers
1k views

OAuth2 - Resource Owner Password Credentials grant

The OAuth2 spec describes the Resource Owner Password Credentials grant type and authorisation flow here. I understand that only 'trusted' client applications would be allowed to use this grant, for ...
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0answers
41 views

Secure access of web application on a newly created AWS instance using the associated keypair

I create an AWS instance using a private AMI (Linux) with an embedded web application (Jetty) which is activated on instance start. As soon as the instance is launched first time, I want the ...
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2answers
405 views

client SSL authentication .pem file and .crt files

So I have minimal knowledge of security really but I'm a primary developer on an application which handles some sensitive data that we want to be secure. The application communicates with one other ...
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2answers
81 views

Encryption mechanism

I want to send data over the Internet securely. For that, I am using an public key of the receiver to encrypt the data. In this case, if an intruder in the network modifies the data, like placing the ...
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1answer
89 views

Single sign on - is this a secure way to log in?

I am fiddling about with a sort of single sign on procedure. Let's say there is site1 and site2 and both use an SSL certificate. Users are signed in on site1. I was wondering what the experts think ...
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1answer
127 views

Is it legal to “use” security vulnerabilities [closed]

I understand that the answer to questions like this depend on country, but I'd like to get an idea what the usual approach to cases like this are. Heres the case: I found a security hole in one of ...
4
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2answers
305 views

Safety of using web based proxy?

Lets say for example I have to use a public online proxy like https://www.zend2.com to load a PHP webpage controlled by me containing sensitive data over HTTPS. How would I make sure that the proxy ...
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0answers
60 views

Allowing third-party clients to authenticate with an app server

I'm working on an app that is planned to be licensed to OEMs, who would in turn offer it as a service to their users.  We would host the app server and the OEM would optionally host the app's web ...
21
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3answers
2k views

How is Google Chrome managing authentication to sites?

In Chrome, every tab is its own process. Yet, logging in to a site, say, Facebook, persists across tabs. For that matter, in many cases, it persists across OS reboots. This seems inherently very very ...
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1answer
593 views

Web app with iframe and user - how to deal with session?

We have application which will be in iframe. Partner sites can use our application - put iframe in their sites. Partner site has users with money, who will use our application in iframe to buy items. ...
3
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1answer
219 views

Do non-browser clients work around Gmail's 2-factor authentication?

If you use a client like mutt to access your mail, you probably know that it doesn't support 2-factor authentication. It still prompts only for a password - either your account password or, in the ...
3
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1answer
1k views

How is NFC tags copy prevented?

Ten years ago, we opened our building's front door with a badge. Five years ago we paid public transports with an RFID card. Today we pay our bread with the same system and tomorrow we would probably ...
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1answer
1k views

Why use an authentication token instead of the username/password per request?

The author of http://stackoverflow.com/a/477578/14731 recommends: DO NOT STORE THE PERSISTENT LOGIN COOKIE (TOKEN) IN YOUR DATABASE, ONLY A HASH OF IT! [...] use strong salted hashing (bcrypt / ...
3
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2answers
950 views

Authenticating REST API using Access Token

If you have a REST API, which when you log in from the client side, generates an access token for the client, which is then stored in local storage and used for all authentication from this point on. ...
67
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5answers
7k views

How can my employer be a man-in-the-middle when I connect to Gmail? [duplicate]

I'm trying to understand SSL/TLS. What follows are a description of a scenario and a few assumptions which I hope you can confirm or refute. Question How can my employer be a man-in-the-middle when ...
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2answers
93 views

On password change in a web application, should it log users out

When a user is logged into a web-based application in multiple tabs, and changes their password should it automatically log them out of the other tabs? The use case is an account is compromised, the ...
3
votes
2answers
146 views

How to prove flyer was (not) authored by specific person?

Let's say we create a flyer in some desktop publishing software (e.g., InDesign, Illustrator), physically print it and post it somewhere. We don't want inauthentic claims of authorship. Is there a ...
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1answer
72 views

What is the point of hosting database externally?

Following the breach of avast:forum.avast.com they decided to host the database externally@id.avast.com. My question is, what is the point of hosting the database externally since when you get remote ...
3
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3answers
169 views

Is it possible to successfully exploit a vulnerability on a router remotely if

...its remote administration feature is locked down to a single IP/Range? If so, why? This has been an ongoing office debate for a while now, I claim that it would be possible as it is likely to be ...
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2answers
146 views

This protocol is vulnerable, but why?

I know that the following authentication protocol is vulnerable, but I can't understand why. A and B share a secret key K (64 bits) R1 and R2 are two 64 bit numbers A-->B: I am A B-->A: R1 ...
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3answers
256 views

Order of authentication and authorization

This is my first question here in Information Security SE. Is there a recommendation to help telling the scenarios where authentication should precede authorization from the ones where authorization ...
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2answers
136 views

Remember Me vs Remember Email

From what I have noticed, there is very few services that offer the Remember Email over Remember Me or Sign-in Automatically. These options really do make the life easier for the end-user of ...
3
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4answers
179 views

Storing Old Password History and Information

Google, Facebook, Twitter, and several other services still knows the older passwords which we used on our accounts. At times, I can not reuse the same password as I have. Then with Google, if I type ...
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1answer
145 views

How to secure my REST API once user authenticates with Google on mobile client?

In my application, I build REST APIs so that user can interact with my application server. Since I do not want to maintain User/Passwords, my iOS app authenticates client using Google. This all ...