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12
votes
5answers
2k views

Why are certificates limited in time?

If a certificate has a limited duration of, say 5 years, but it gets somehow compromised after 2 years, waiting the 3 remaining years for it to get invalid is not a real solution to the breach ...
12
votes
1answer
1k views

When does iOS check validity of enterprise certificates?

Here is an article that should give a little more context (and see my comment on it, same username, for additional info). iOS developers are able to distribute apps outside of the App Store using an ...
10
votes
5answers
2k views

Input Sanitization vs Output Sanitization [duplicate]

In the bits that I've searched about this, I've seen a few people declare as word-of-god that you should only sanitize outputs and not inputs. Why? Would it not be safer to cover both ends?
10
votes
5answers
2k views

Should a website limit characters that can be entered in its fields?

I got into a (somewhat heated) discussion with my colleague today about what characters our application should accept. This was prompted by the discovery that you can enter anything in the search box ...
10
votes
3answers
2k views

Should IP addresses be validated to prevent SQL Injection?

In PHP I retrieve a user's IP address ($_SERVER['REMOTE_ADDR']) to use it in some MySQL queries, but I do not validate them to be true IP addresses. Should I validate user IP addresses before using ...
9
votes
6answers
2k views

Filter user input before the database or upon display?

Given a web application where user data must be properly escaped to avoid XSS, is it better to try to remove the "bad stuff" before it enters the database, or is it best to allow it in the database ...
9
votes
1answer
231 views

E-voting: receipt-free, verifiable, and anonymous

Background In response to a system design concept, a question was posed: How do you achieve electronic voting, anonymity, and verifiability at the same time? I was informed that most experts in ...
7
votes
3answers
511 views

What are the risk implications of not verifying referer header on login form?

Imagine a generic web application with a login form to access the application. Regardless of how the actual authentication is performed, what are the implications of not checking the referer header to ...
6
votes
5answers
6k views

XSS : Blacklist characters vs. whitelist

I have been studying to prevent my web app against XSS. I read about it on OWASP and other security channels, they all say that use ESAPI and similar library, and also do input filtering through ...
6
votes
3answers
169 views

Obtaining e-mail address at registration

In a registration form the user is asked for his e-mail address. The e-mail address will be validated for the correct format (e.g. at the least contains @) and I'm considering checking if it's already ...
6
votes
2answers
2k views

Canonicalization & Output Encoding

I'm reading OWASP's Secure Coding Practices Checklist and under their "Input Validation" section they have an item that reads: If any potentially hazardous characters (<>"'%()&+\\'\") ...
6
votes
1answer
582 views

White list or black list sanitation for international input?

There seem to be so many ways to create nefarious input that white-listing what input is good usually feels like the safer, simpler option. For instance, one can fairly easily craft a white list ...
5
votes
2answers
810 views

Authentication: Username (email) and password hashed together in one database field

I am currently developping a platform with a PHP framework for our client. The head of the client's IT department wants us to handle authentication with one database field containing ...
5
votes
3answers
8k views

What data should I validate when validating X.509 certificates using Java?

Well I began with PKI a year ago with RFID system at school. Now I'm asked to implement this in my job. I understand most part of the idea. The doubt is about the certificate validation. I know it ...
5
votes
2answers
290 views

Should you let users know if an email has been taken during registration validation? [duplicate]

In many web applications, email is required to be a unique field, and users aren't allowed to register an account if their email already exists in the database. When performing validation on the ...
5
votes
1answer
43 views

Who can certify RNG according NIST SP800-22?

I have written my own random number generator as a C library and I tested it on NIST Statistical Test Suite. Now I would like to get a certification to have a formal proof that my C library generates ...
5
votes
2answers
187 views

How can a certificate be valid in the Hybrid Model but not in the Chain Model?

All dates in European format! I am learning about validity models, but the solution for this assignment confuses me. Translation: The relevant data for the applicable certificates are shown ...
4
votes
3answers
2k views

SQL injection using letters and numbers?

I was wondering if it is at all possible for a hacker to perform an SQL injection attack using just letters and numbers. For example, let's take a look at this PHP code which uses regular expressions ...
4
votes
2answers
355 views

Server checking client's password without ever coming into possession of it

tl;dr: I am wondering what the best way is to check a password when the client does not trust the server. I know of two common ways servers can check if a user's password is correct: The server ...
4
votes
1answer
1k views

Is ASP.NET Event Validation completely secure?

I am currently testing a ASP.NET web application for its security. Doing so I came across the event validation mechanism. Is there some way to bypass it? How much assurance is there that it cannot be ...
4
votes
3answers
55 views

Input validation: how to do it if I must accept HTML as part of my input?

I'm writing a service which receives FHIR data and it stores it. FHIR is an HL7 healthcare information standard format which contains HTML by definition, embedded into a JSON or XML, (to ensure ...
4
votes
2answers
133 views

Could server honesty be audited by remote peers without said peers having sole (or any) control of the server?

Suppose for some reason, you and your peers absolutely positively have know that a server is acting honestly. Could the server behaviour be audited remotely through some mechanism of randomly ...
3
votes
5answers
1k views

Is it secure to use jQuery on the server-side for user input validation?

I'm thinking about using jQuery on the server-side (node.js) to validate user input (filter tags, remove every attributes except href, rel, target & style, modify css rules which are applied ...
3
votes
4answers
1k views

Is it ever safe to skip server-side validations?

I am working on a web app with a sign up form like below. The validations are all done client side using http://formvalidator.net/. I am well aware that client-side validations can be bypassed, but I ...
3
votes
2answers
179 views

In practice, does crypto software accept a *.com or or even a *. certificate?

Assuming this will be done with your own PKI, and not a public trusted CA. Considering that *.sub.domain.com is valid, and so is *.domain.com is valid, is it technically possible to issue *.com and ...
3
votes
2answers
2k views

Validating an SSL certificate chain according to RFC 5280: Am I understanding this correctly?

we're in the process of replacing certificates with SHA1 hash due to Google's move to let them appear less secure in Chrome. The replacement certificates use a different intermediate CA than the ones ...
3
votes
2answers
308 views

Valid Characters For Magnetic stripe

We bought some Magnetic stripe cards and I'm writing a program that will get talked to by a mag card reader. What I need help with is that I can't, for the life of me, find out what characters are ...
3
votes
2answers
182 views

Email & Domain ownership?

Most hosting companies, such as mine (hostgator) give the following notice when providing a contact email: Email address that you can be contacted at. This should be an email address that is not ...
3
votes
1answer
93 views

Server Certification Processes

We are considering a certification process for new internal server builds before they are allowed to be placed into production. That is, the system administration team will send the server up to the ...
3
votes
1answer
64 views

User-friendly TLS certificate validation

I'm designing an application in which clients generate their own TLS certificates ad-hoc (there's no central authority). When two clients interact for a first time, I need for them to mutually check ...
3
votes
1answer
87 views

Validating correctness amongst untrusted answers

I'm toying around a distributed computing project. The client application asks for a problem to solve. The server returns a problem description from a "problems pool". When the client finishes, it ...
2
votes
4answers
1k views

Bypassing Web Application input validation

A malicious user can use Base-64 or other encoding scheme to bypass web application input validation or to bypass some external Web application firewall. Since these encoding schemes are infinite how ...
2
votes
1answer
154 views

Exploiting mailto links

Supposing that the user has the power to include any content after mailto: snippet, are there any possible security vulnerabilities? Example: The user says their email address is foo. The link on ...
2
votes
1answer
169 views

SSL certificate to protect spoofing of API server

I have a program written in Python that checks the validity of its license key with a remote server. Am I right that an SSL certificate would make it possible to prevent spoofing (host redirects for ...
2
votes
1answer
88 views

How do I audit the effect of security policy on a computer?

I have developed different templates for local security policy. I have been using the program Nexpose to test the effects of those security policies but so far I am not able to detect the visible ...
2
votes
1answer
159 views

Server side validations for file upload to prevent DoS on HTTP server

I am aware that client side validations can be easily bypassed by means like disabling javascript. I would like to know the things to be checked while doing a server side validation for file upload. I ...
2
votes
1answer
26 views

Explain OWASP Data Validation best practice example

I'm looking at the OWASP Data Validation page trying to figure out what they mean with the "Best Method" for "business rule validation". I quote them here: Example - Scenario You are to ...
2
votes
2answers
643 views

How to ensure an email address is not free webmail or ISP address?

I notice security companies such as Rapid 7 prevent people signing up with either free email accounts, or accounts provided by ISPs: ...
2
votes
2answers
149 views

Using External Certificates on a network that doesn't permit outbound HTTP/S access

Some highly secure networks and DMZs prevent all communication to outside hosts. This can cause issues with validating externally signed data I can guess that issues with signature validation occur ...
2
votes
1answer
185 views

Finding the type of SSL certificate with cURL

This is a part of curl's verbose output when connecting to the HTTPS site of Google. * Server certificate: * subject: C=US; ST=California; L=Mountain View; O=Google Inc; CN=www.google.com * ...
1
vote
3answers
140 views

Strong email validation. Is it really necessary?

I am working on one of my projects where users don't need to register or login to post an advert, but they have to provide email so that a confirmation link will be sent to their email address for ...
1
vote
1answer
67 views

Certificate expiry validation - in what stage?

I'm implementing certificate expiry validation for a client. I'm not sure about the following. Is there a standard/popular implementation regarding the order of validation- Check if the ...
1
vote
3answers
168 views

Make all form inputs safe but allow any type of input including code

Pastebin allow you to (along with plenty of other sites) input code into there forms. I know that this can be a huge security threat if not done properly so I would like to know how they go about ...
1
vote
2answers
231 views

Is php DOMDocument::loadXML completely secure?

Our application is using loadXML extensively to recieve data(input) from the users. Other than the usual checks for SQL injections and XXS, are there any known risks in parsing the xml file using ...
1
vote
1answer
705 views

Behavior when validating an expired certificate chain

I have the following situation: A server certificate (CServ) is signed by self-signed certificate (C0) A client certificate (CCli) is signed by CServ Client's trust-store contains C0, so the client ...
1
vote
3answers
1k views

Validate hmac with hashed stored key

What if an HMAC is correctly generated and sent with the data to the server, so far I know the server needs to know the original data with which the MAC was created in order to re-create the MAC and ...
1
vote
2answers
258 views

Security issues on allowing Special characters in input field

I am building a web application, in which I am required to let user enter any character(even special characters - ~!@#$%^&*()_-+=|\{}[];:'"<,.>) in an input field. To mitigate the problems ...
1
vote
1answer
26 views

Expand user login in Path - Filter malicious values

I have a function that takes a pathname and substitutes every occurrence of '%u' with a given String. For my scenario this given String is the login that a user/attacker enters via ssh during ...
1
vote
1answer
67 views

What could happen if regex metacharacters using named capturing group are not encoded?

Let's say that a web application take a specific input from the user (e.g., search form), apply a Java regex with named caputring groups on it and use the final output to do other stuff (e.g., look ...
1
vote
2answers
172 views

Should I validate authentication form inputs?

I've got a login page with a form where they can input their account's email address and password. I'm doing the following things before even attempting to authenticate a user: Validating the email ...