An application that is accessed over a network such as the Internet or an intranet using a browser.

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6answers
1k views

Where to start with security testing?

Starting with a QA team that deals mainly with functional requirements testing and has little real security testing experience, what simple practical things should the QA team start doing to start ...
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4answers
348 views

Sensitive information was placed in a publicly accessible folder. Who is responsible and how to proceed?

Background We have an IT staff who manages our server and a web developer who is not on the IT staff and has no root access to the server. All involved do very high quality work and I do not consider ...
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6answers
1k views

Ads appearing in our application when they should not be

I received a strange issue reported by one of my web application users. Apparently they are getting "ads" within the browser window when using my application. I didn't add advertisements at all. It's ...
12
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7answers
4k views

Should we force user to HTTPS on website?

Should we force website from HTTP to HTTPS , one of the method is using .htaccess: RewriteCond %{SERVER_PORT} 80 RewriteRule ^(.*)$ https://www.example.com/$1 [R,L] But what I notice is that some ...
12
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3answers
19k views

Is it possible to execute a php script in an image file? [duplicate]

I have an image upload php website. Users can upload images to my website. A user claims he can hack my website using an uploaded image. I opened all the images that he uploaded to my server with ...
12
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3answers
27k views

How can I use this path bypass/exploit Local File Inclusion?

I have tried to run a vulnerability scanning script (Uniscan 6.0) on some websites and then I found a site which is exploitable with this following path. (included a word "invalid" , params/website ...
12
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3answers
1k views

What security measures should be taken when running a Linux web server out of our office?

I am interested in running our company's web server from our local office. The office makes use of file sharing and NAS devices among other common office protocols. The worst case scenarios I've ...
12
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4answers
4k views

Challenging challenge: client-side password hashing and server-side password verification

We have a website where users need to log in to access privileged information. Obviously we are using SSL, but I also want to avoid plaintext passwords from accidently ending up in server logs, or ...
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3answers
3k views

Using file extension and MIME type (as output by file -i -b) combination to determine unsafe files?

We allow users to upload a number of files, all of which we either send over to scribd (doc, xls, ppts, etc) or display as a video ourselves (flv, mov, mp4, etc in flowplayer). To avoid users ...
12
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4answers
694 views

How should I secure a contact form that appears on every page of a website?

My client has a small "Contact Us" form on every page of their website. They are adamant about not including CAPTCHA verification on these forms, to keep them easy to use, but I feel it is my ...
12
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4answers
730 views

What does defense in depth entail for a web app?

I'm assuming it means different layers of security from app-level security to server hardening to personnel training, but what are each of those layers and what are some good resources for each level ...
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2answers
311 views

Preventing Voter Fraud on a Social Media Contest

I'm creating a contest that will allow users to login using their Facebook & Twitter accounts and submit votes on videos. My clients concern is that users will game the system by logging into ...
12
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4answers
1k views

Sending HTTP 403 as. 200 - “Silent Identification of Admin”

A researcher recently reported an issue in a site about using script on a 3rd party site to discover if a user is an admin. Here's the scenario: Main site is target.example Attacker site is ...
12
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2answers
1k views

Interpolique: transparently preventing SQL Injection and XSS with base64 encoding, what happened?

For the keynote at The Next HOPE a couple of years ago, Dan Kaminsky unveiled Interpolique (the talk is really fun btw). The problem he raised was how to defend against injection attacks, including ...
12
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3answers
4k views

Is it possible to use a GPG or SSH key for web based authentication in a secure fashion?

Let's say hypothetically I am writing a web application targeting technically inclined, security-conscious users who have no problems generating and using GPG or SSH keys. Is it possible to use said ...
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4answers
3k views

Authenticating without a database

I've been inspired by a question over on Code Review, which boils down to: What is the proper way to authenticate a user without a database? Would it be the exact same process if you stored ...
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4answers
1k views

Why should I use whitelist on a WAF?

I was studying different WAFs, from open-source (such as ModSecurity and NAXSI) to commercial solutions (Imperva, Citrix, Fortinet, etc.). Many people state that having a whitelist-based WAF is far ...
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2answers
2k views

What does this injected code do?

One of my sites has just been hacked as this code has been inserted into random(?) files and places within the files. Does anyone understand what it is trying to do? I would welcome anything that may ...
11
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4answers
19k views

How to know which database is behind a web application?

I've read that different databases (mysql, sql server,...) have different vulnerabilities and that they are vulnerable to some specific sql injections. When attacker try to perform a database attack ...
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6answers
3k views

Is there a security risk running web apps in debug=“true”?

This is a copy of the original question on Stack Overflow which didn't get much love and is probably more relevant here: There are plenty of performance reasons why apps shouldn't be run in ...
11
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7answers
2k views

IP address black list

My website has a black list of IP addresses. The web application, in some way, detects all invalid, suspicious influences to it and remembers IP address and denies any requests from that IP address. ...
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3answers
699 views

Is stripping out < and > characters an effective way of preventing XSS?

I'm guessing that HTML encoding the input would probably be a better solution, but I'm curious if just stripping out any < and > characters would be an effective defense against XSS attacks. ...
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2answers
10k views

Implications of Trace/Track Methods on Apache

When performing vulnerability scans using Nessus, against a host running Apache, one expected result is always "HTTP TRACE / TRACK Methods Allowed". While this result only has a base CVSS of 4.3, I ...
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5answers
14k views

Benefits of identifying clients based upon the “X-Forwarded-For” or similar HTTP header in addition to Client IP

The X-Forwarded-For header is used by some HTTP proxies to identify the IP address of the client. The wiki page (linked above) mentions that ISPs may use this header as well. In addition there are a ...
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4answers
11k views

What SSL key should I make for IIS: RSA or DH? What bit length is appropriate?

I'm creating an SSL cert for my IIS server and need to know when I should choose the Microsoft RSA SChannel Cryptographic Provider or the Microsoft DH SChannel Cryptographic Provider. Question 1 Why ...
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4answers
1k views

How dangerous is it to store password in plain text on sites like GitHub?

I have a few private repositories set up on GitHub for some of the projects I am working on for my company. These applications connect to databases and I have database authentication credentials ...
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5answers
7k views

Is it okay for API secret to be stored in plain text or decrypt-able?

Aren't API keys considered usernames and API secrets considered passwords? Why is it that API servers like Amazon Web Services allow you to view your API secret in plain text? It makes me think they ...
11
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3answers
813 views

Is Gmail showing images by default a good idea for privacy?

Google have decided to show images in Gmail messages accessed via the web, iOS and Android by default: Instead of serving images directly from their original external host servers, Gmail will now ...
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3answers
1k views

How much information about the reason for an unsuccessful login should a web application give?

After an unsuccessful login attempt, should I inform the user about its reason? Or more generally, how much information about the reason for an unsuccessful login attempt should a web application ...
11
votes
1answer
550 views

Public XSLT & XML playground (with PHP DOMDocument, etc.) Security Risks?

Let's say I want to set up a sandbox or playground in PHP that users can use to create (or paste in) XML and XSLT, then transform the XML via the XSLT (by means of PHP 5's DOMDocument and related ...
11
votes
1answer
2k views

How is time-based SQL injection different from other types of SQL injection?

I understand what a time-based SQL injection is, and I understand how it works (at least how it's detected/exploited). However, is there anything in specific which makes this type of injection any ...
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2answers
1k views

Security quiz for developers

Does anyone know of a short security quiz that could be administered online, to test the security knowledge of a developer? I'm looking for something simple to administer and simple to grade, ideally ...
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4answers
3k views

What is the right way of storing database connection strings from the security point of view?

What are recommendations, best practices and have-to-dos regarding handling connection strings in web applications? What things one should never, ever do?
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1answer
2k views

Strict Transport Security — max_age value

I've been wondering what max-age should the HTTP Strict Transport Security header have. Both paypal and lastpass sites leave it very low: 500 (seconds = bit over 8 minutes) market.android.com has it ...
11
votes
1answer
307 views

WAF Process Creation for Integration of IT and Business

A client has asked me to help them out with their WAF processes. Currently they have a few critical web applications being protected by a couple of WAFs. I have managed to get the WAFs tuned and ready ...
11
votes
2answers
987 views

Is request signing (digesting the request body) in a REST API necessary?

I am currently engaged in a debate and I wondered what the community's opinion on this was. We see REST APIs which just require basic authentication (perhaps HTTP) or OAuth. We see REST APIs which ...
11
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1answer
786 views

Webapp2 security

I am coding a REST web application that runs on Google App Engine, it authenticates API requests to privileged data using sessions by cookies provided by webapp2_extras.auth and ...
10
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3answers
5k views

How secure are sha256 + salt hashes for password storage [duplicate]

I started reading about password hashing recently on multiple sites like this page on crackstation and others, and for what I have understood, I should avoid using hashing algorithms like md5 and sha1 ...
10
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6answers
607 views

What are web attacks which users can run code on your servers?

I hear stories about insecure web servers and sites which people (or bots) break into and execute their own code on the server. My question is how is that possible? I heard of people putting their ...
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votes
4answers
500 views

Should a web application return true http errors?

Exception and error information can be used by a malicious user to map out the API of an web application, so it is routine to see security checklists to advise returning only a "Please contact your ...
10
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6answers
4k views

Security review: “HTTP header user-agent has been set to (something)”

We got a security review done of our PHP code and they team advised this in their report (amongst other things): /appdir/ Details The HTTP header user-agent has been set to \" . Request GET ...
10
votes
4answers
5k views

How effective are reverse proxies as a web application security measure?

How effective are reverse proxies as a web application security device? Which types of threats do they mitigate against and which don't they? For example are they more effective in preventing ...
10
votes
1answer
7k 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 / ...
10
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4answers
558 views

Does my UI need to be secure if my API is?

I'm working on a project that is creating two new, separate web modules (possibly even on different servers) to support a new web application, with one serving up a static JS-based UI and the other ...
10
votes
3answers
496 views

How could the string \";alert('XSS');// be used for XSS?

I was using Burp Suite for some testing and I noticed that they included the following string: \";alert('XSS');// as an attack string for an XSS payload. How could this string be used to execute ...
10
votes
4answers
469 views

When changing a password using a WebPage, must the old password be entered on the same screen?

There is a convention to always prompt for the old password on the same page as the one where the old password is being changed as shown below. Is it acceptable from a security perspective to allow a ...
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6answers
8k views

Why is php not used for banking sites or for a banking transaction?

Other programming languages popular on the web, such as Java and .NET, are used for banking sites. However, I've rarely (if ever) seen a PHP application designed to be deployed for a banking site. ...
10
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3answers
483 views

What simple security considerations can I / should I make for a read-only API?

Right now I'm setting up an API, to be consumed on the client-side to set up a directory site. I'm wondering what extra steps I need to take just to prevent people from gaining write access to the ...
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3answers
3k views

How bad is a Self Contained XSS attack?

Some of you might be familiar with this attack called Self Contained XSS. I recently stumbled upon this article about it. So how bad this kind of attack can be, even though this doesn't have access to ...
10
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3answers
486 views

Should I ask a user to re-authenticate if the browser thumbprint changes? Is a server side library available?

Is there a security benefit to using the browser's thumbprint in addition to a session identifier to identify a unique session? Would it then be advisable to ask the user to reauthenticate (or simply ...