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Questions tagged [client-side]

Client-side refers to operations that are performed by the client in a client–server relationship in a computer network.

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46
votes
3answers
10k views

Are virtual keyboards not necessary anymore to protect against keyloggers?

My bank has issued a new version of their online banking site. This new version has no virtual keyboard to enter the PIN. I asked them how are they protecting me against keyloggers but I didn't ...
40
votes
6answers
12k views

Sending a client-side high-score to a server securely [duplicate]

I'm creating an web-application that has a simple javascript game in it. Once the player finished playing the game the high-score is sent to the server and saved. After a specific period the player ...
37
votes
5answers
10k views

How secure are my passwords in the hands of Firefox using a Master Password?

I'm relying on Firefox to remember my passwords, using a Master Password of more than 25 characters. How secure is this set-up?
36
votes
9answers
13k views

If “you can never trust the client”, then why do companies such as Valve rely solely on client-side verification?

In video games, most anticheat software is run clientside (e.g. PunkBuster or Valve Anti-Cheat)- but isn't one of the first rules of security to never trust the client? If so, then why do these ...
30
votes
7answers
10k views

Client side password hashing

Edit: Updated to put more emphasis on the goal - peace of mind for the user, and not beefing up the security. After reading through a few discussions here about client side hashing of passwords, I'm ...
30
votes
3answers
13k views

What useful things can I do with the html5 “keygen” element?

There's a new* keygen element in the html5 spec. It's supported in major browsers excepting Internet Explorer and Safari. Here's what it looks like: <form action="processkey.cgi" method="post" ...
28
votes
9answers
3k views

Why do some people really hate security via client-side?

For instance, lets look at a common login system for a website HTTPS connection is made User submits credentials via POST Server-side code hashes the password and looks if it matches the user name ...
26
votes
5answers
8k views

How does preventing automatic download of pictures help to protect my privacy?

When viewing some emails in Microsoft Outlook, if the sender has included images, I get the following option appear at the top of the email: "To help protect your privacy, Outlook prevented ...
25
votes
7answers
6k views

Is it possible to modify your user agent http header for malicious use?

The Google crawl bot uses the user agent "Googlebot", and I am wondering if this knowledge can be used maliciously. Let's say in a random website, the Googlebot user agent is allowed to access an ...
23
votes
12answers
12k views

Is there a way to hide HTML source code yet keeping it effective?

I have a website with a client-side HTML contact form created manually (not as output of an HTML constructor like PHP): <form action="mailto:someone@example.com"> Email Adress:<br> ...
22
votes
8answers
6k views

How can I re-use my password and still protect the password if it is exposed from one source?

I know that all servers should at least store my credentials as hash(password + salt) + salt, with a secure and well known hash function and a salt unique for me, generated from a secure and well ...
22
votes
6answers
2k views

Is it fundamentally possible to validate that an unmodified version of your client connects to your server?

I'm cross posting this question from Programmers.SE because I think it's equally on-topic here and would like to pose the question to this community as well. This seems like a programming question ...
19
votes
3answers
13k views

How do RSA SecureID ® Keys Work?

I have been using RSA SecureID ® Keys for quite some time now (perhaps 10 years), for things such as securely my home banking account online or accessing my company's network of computers from home. ...
18
votes
5answers
43k views

How to do client side hashing of password using BCrypt? [duplicate]

I am migrating an old application which used MD5 hashing to Spring Security with BCrypt encoding of passwords. I want to encode the password on new user creation page, change password page and on ...
18
votes
3answers
20k views

help understanding client certificate verification

I am creating an API that only certain computers should have access to. Communication will be via SSL between the server and the clients. In order to verify that a client has access, I would like to ...
14
votes
3answers
8k views

Do client certificates provide protection against MITM?

I'm looking for a way to protect clients from a MITM attack without using a VPN, and ToR. My thought is that client certificates might do the job, but I'm not entirely sure since not too much server ...
13
votes
3answers
747 views

Can I use the same password both for SRP and for client-side encryption?

Suppose a less-than-trusted server is used to store users' confidential data (encrypted at the client side), and both tasks - authentication and encryption/decryption - should be doable with a single ...
13
votes
3answers
462 views

Can client-side hashing improve after-the-fact security in response to password leaks?

Several questions on this site address client-side password hashing, and none of them admit to any security benefit beyond protecting other sites the user might use the same password for. However, ...
12
votes
12answers
1k views

How to guarantee that password is hashed on server-side?

I'm worried when I send a password to a server, even with SSL or TLS, that the server stores the password in cleartext. Is this the case? If yes and the server gets hacked, all passwords are available ...
12
votes
4answers
4k views

Preventing reverse-engineering of client application

I have a web service which is used by a Flash client. Both the service and the Flash client is produced by me (read: my company). The Flash client communicates with the server over HTTPS. One of the ...
12
votes
5answers
6k views

How can I securely authenticate the client application sending me data?

We have a web service logging/recording user data sent over https by our client application. Is there a way to securely ensure that the data is getting sent by the client application and not by a fake ...
12
votes
2answers
3k views

How to protect against clickjacking attack but allow legit iframes?

I'm aware of modern anti-clickjacking approaches, such as X-Frame-Options header or framekiller scripts. But all these tactics prevent content to be inside iframe. But what if there is a requirement ...
11
votes
6answers
3k views

How to securely store my passwords?

Regarding this: Are passwords in memory? So does someone have a good idea on how to securely store my passwords? The: "passwords.txt" -> ctrl+c; ctrl+v a passw is not very secure. I have passwords ...
11
votes
5answers
40k views

How to validate a client certificate

My understanding is that when using a client certificate for security one issues a private and public key cert (for example X509) of some sort and sends that of to the consumer of the service that one ...
11
votes
2answers
11k views

How to remember a trusted machine using two factor authentication (like Google's system)

We are developing a web application that will use two factor authentication. We are likely to try and emulate something similar to that used by google, where to login you enter a username and password,...
11
votes
3answers
2k views

If I am obliged to store a password/certificate on a client side, how can i make sure that it is protected?

In certain cases we need to establish a key/password/certificate as a first timer and then as a client we need to use this key/password/certificate to get authenticated. Therefore the key/password/...
9
votes
5answers
7k views

How To Prove That Client Side Javascript Is Secure?

Imagine that you have a web application that encrypts the user's data, such as a note or spreadsheet, on both the server and client. The normal process for a user using this web application is ...
9
votes
2answers
3k views

Security Concerns on clientside(Javascript)

We are going to design and implement a UI for a big website. Owner of the site is really cautious about security issues. I wonder if there is a check list for security issues at the client-side ,while ...
9
votes
5answers
236 views

Citations for inadvisability of globally unique password

I am looking for an authoritative source to back up my position in a disagreement over password policy. I am having a disagreement with a client about the user identification/authentication process ...
9
votes
1answer
2k views

How should I protect in-app Android payments when using a separate server?

I am currently implementing Android in-app payments, and am wondering what attack vectors I should look out for. I have a simple application to view server-generated content. I want to allow the user ...
9
votes
1answer
8k views

Drawbacks of storing an authentication token on the client side?

I am working on an ASP.NET MVC web application, which fetches its data from an API in the back. So authentication is currently done via ASP.NET Forms Authentication, which means the client sends email ...
8
votes
3answers
14k views

Certificate Chain checking

I have a very specific question. A client verifies a server by taking the certificate and checking specific values and that the digital signature of the intermediate CA is correct (according to the ...
8
votes
2answers
3k views

Using Client-side certificates for Authentication

Why aren't client-side certificates used for Authentication? Then user has to remember only 1 password to unlock his windows account which stores the certificates. I understand that if user access ...
8
votes
1answer
2k views

Asymmetric / end to end encryption for web messaging app

Background I'm trying to design a secure and sustainable web app for messaging. The purpose is to learn how to create secure web application. The application is suppose to be written in Javascript ...
7
votes
2answers
4k views

Is it safe to use createHTMLDocument to sanitize HTML?

i'm wondering how safe it is to use createHTMLDocument to do HTML sanitization. I've tried to implement it like this: function sanitize(string) { var elm = document.implementation....
7
votes
2answers
5k views

Risks of client-side encryption using Stanford Crypto Library

I'm building a simple web application for encrypted chat. Each message will undergo 256-bit AES encryption on the client side, using the Stanford Javascript Crypto Library. No unencrypted data or ...
7
votes
2answers
991 views

Client-side attacks with custom malware in penetration tests

I regularly perform pen-tests against web applications, operating systems, etc. Occasionally, I'm luck enough to do a 'red-teaming' exercise and get to attack at all conceivable points of a network (...
7
votes
2answers
2k views

How to implement client side encryption for CalDav & CardDav content?

I'm looking for a client-side encryption implementation that would be able to secure CardDav & CalDav data so that they couldn't be compromised even by the hosting provider. Server side: PHP or ...
6
votes
5answers
16k views

How to securely share key between two remote devices?

Assuming I have a server/client topology, currently I'm facing the problem that I want to generate some key on the client side and somehow make the remote server get it securely. I'm using AES on ...
6
votes
2answers
1k views

Is it better to hash n*x times in sha1 or n times in sha512 on the client side?

I already know I"m going to hash the user's password n times in either sha512 or n*x in sha1 before it is sent to the server. Once at the server, I'm going to use bcrypt set to use ~1/100th of a ...
6
votes
1answer
4k views

Verify CDN javascript's integrity

CDNs speed up the loading of websites by allowing caching for frequently used javascript libraries like jquery. How do we know if they have modified the javascript before serving it to my clients? E....
6
votes
1answer
8k views

Is it safe to give an Oauth token to client side javascript so it can directly make requests to a server?

I currently have a simple backbone.js application served from my domain (example.com), which is provided an Oauth token. Specifically, I pass the Oauth token through my page template into the ...
6
votes
5answers
953 views

Don't trust the client?

I am a web developer, and have been trying to learn a bit about security, and the thing that seems to be the biggest principal is just to trust the client with as little as possible. Is this a correct ...
6
votes
2answers
5k views

Secure OAuth 2 flow for client-side or mobile app

I'm implementing an API and a client-side web app, and they are supposed to communicate via an API and use OAuth 2 for authentication. I can't get over my confusion on what's the right way to ...
5
votes
4answers
4k views

How to prevent attacks against client side validations?

I have a login form where am accepting Mobile Number of the User for login. When Mobile Number is submitted, am calling a JavaScript to validate the Mobile Number. My client side validations consist ...
5
votes
2answers
22k views

How is the Premaster secret used in TLS generated?

I believe that it uses some combination of the random values sent in the hello messages. From RFC 2246: (TLSv1.0) RSA encrypted premaster secret message Meaning of this message: If RSA is ...
5
votes
2answers
2k views

Web & insecure HTTP - Using RSA for encrypting passwords on the client side

I used client side password hashing in my register and login project. Its purpose is to prevent passive adversaries/eavesdroppers from discovering users' plaintext passwords when HTTP requests are in ...
5
votes
4answers
224 views

booting from linux CD and visiting https website only

my friend wants to make sure he visits certain websites very securely. Is booting from linux cd and visiting only https website secure, meaning only he'll have access to data? He'll be on wi-fi of ...
5
votes
1answer
9k views

Correct way to perform secure two way encryption on a web site

I'm currently working a project that requires me to store sensitive information (mainly passwords and other information) on a web server via a standard python/flask website. This information is to be ...
5
votes
4answers
1k views

Secure authentication: partial client-side key stretching… please review/criticize my idea

I am trying to figure out what would be the 'perfect' authentication system for a website. On one end, we know that simple hashing algorithms can be brute-forced or cracked in other ways. Hence why ...