Tagged Questions

10
votes
3answers
345 views

What bad coding practices makes a browser extension vulnerable?

I'm trying to scan JavaScript files for vulnerabilities using JSHint. Specifically, I'm scanning the JavaScript files of browser extensions. To look for possible vulnerabilities I'm looking for bad ...
1
vote
1answer
186 views

bypass a regex filtration to perform an xss attack

Does the regex [\w/$!.*-]+$ stop the injection of payloads like : "><script>alert(4)</script> " onload="alert(4)" ...
10
votes
2answers
203 views

What should I look for when auditing a Browser extension / plugin?

I've been asked to do a security audit on a cross-browser plugin for desktop browsers developed by a third party. I am a web developer with a reasonable grasp of Javascript but am not a browser ...
3
votes
1answer
1k views

DOM Based XSS attacks: what is the most dangerous example?

I knew that XSS attacks (“non-persistent” and “persistent”) can hijack user session, deface websites, conduct phishing attack, etc. However, I can't understand what is dangerous of DOM Based XSS if ...
2
votes
1answer
68 views

Return AWS signature over HTTP

I am performing multipart upload to S3 straight from the browser, i.e. bypassing my back-end. My JS code sends a hand-shake request to S3 (a POST), then uploads the file in chunks of 5MB (a PUT for ...
1
vote
2answers
339 views

HTTP Response Splitting

Is this apart of a HTTP Response Splitting attack ? Here below is some code that gets put into a web browser after clearing the url while on the website javascript: var xhr = new XMLHttpRequest(); ...
0
votes
2answers
143 views

Is a browser with disabled scripts and disabled java enough against malware

Is a browser like Firefox with disabled scripts (for example via a plugin like no-script) and disabled java enough to be protected against dryve-by-malware from the internet. Of course this does not ...
1
vote
4answers
950 views

Playing with Referrer Header

There are 2 sites: http://www.site1.com http://www.site2.com http://www.site1.com contains link to http://www.site2.com as <a href="http://www.site2.com/">link<a/> When user clicks ...
10
votes
1answer
369 views

How can I embed iframe securely without restricting its functionality?

I'd want to embed an iframe from untrusted site into web application. Iframe: should be able to run Javascript and browser plugins (Flash, etc.) should not be able to access my web application ...
8
votes
2answers
125 views

Preventing user supplied javascript from posting to external server

I am writing an internal tool that will support plugins written by other developers. Ideally, these plugins would have a Javascript component to allow people to make widgets. Some of the pages these ...
3
votes
1answer
106 views

How can I use certificates to secure my webservices? What is available to javascript?

I have a few web services that are accessed over public wifi connections and I think it would be a good idea to issue certificates to encrypt data, prevent MITM, and invalid impersonation (beyond what ...
8
votes
2answers
187 views

User-specific Subdomains : JavaScript security

If I provide a public-facing website for users on my website at their own subdomain (e.g. bob.myapp.com) under their own control, can I allow them to execute arbitrary JavaScript without putting my ...
2
votes
3answers
1k views

Javascript Malware: How does it work, and how can it be mitigated?

I am wondering how malware gets served through Javascript. I've noticed a few illegitimate pop-ups while visiting some financial websites. I wonder how malware exploits work against the application ...
8
votes
5answers
206 views

Is it a risk to highlight text while reading a webpage?

Whenever a user selects or highlights text on a webpage, an OnClick() event is generated. Some of the web browser security models depends on explicit end user interaction, such as OnClick(), before a ...
1
vote
0answers
95 views

What are potential use cases of script that identifies browser? [closed]

Let's say I've found a way to produce a unique string for each and every browser using pure Javascript (which makes it an alternative to UA strings). Now what I'd like to know is what are potential ...
3
votes
2answers
466 views

Why do I get AV alerts when browsing a web page?

I'm using the latest version of Firefox and Windows is up to date. When I was browsing a webpage and clicked a link the browser displayed "connection has been reset" and AVAST poped-up saying "Alert!" ...
3
votes
1answer
135 views

Client-side cross-site access in SSL environment - when it's still possible to do?

I'm trying to imagine an secure sandboxed environment for an application which is big and unexplored, and may contain backdoors. It would live under chroot/virtual environment with no outgoing ...
1
vote
1answer
119 views

Is the javascript browser tool at printfriendly.com secure for my browser

I use Win Xp Home with SP3 and am pretty aware of security problems. I use Palemoon 12.1, a version of Firefox optimized for windows. I usually use printfriendly bookmarklet to create printable pages ...
4
votes
4answers
2k views

Is WebGL a security concern?

Is WebGL a potential security problem due to the low level access it provides? For example, a web page can attempt to compile and run any shader source it wants. It seems that security would ...
3
votes
2answers
347 views

Can one get infected through visiting a site with a PHP script on it and if yes, how?

I can imagine a clientside JavaScript that gets executed in a vulnerable browser to do some harm, but how can this be done with PHP? Since it's serverside it shouldn't have access to the visitor's ...
9
votes
3answers
744 views

localStorage for apps over https. What expectations are there?

I run an online gradebook. To keep student data private, I transfer all data over https. Now, I'd like to use localStorage to avoid redundant calculations and server requests. However, according to ...
13
votes
5answers
2k views

Preventing information disclosure from browser back button/history?

I have sensitive data that will be hosted on a website, and I would like to prevent the data from being exposed in this scenario: The primary user logs off the application, but does not close the ...
18
votes
2answers
3k views

Why is the same origin policy so important?

I can't really fully understand what same origin domain means. I know it means that when getting a resource from another domain (say a JS file) it will run from the context of the domain that serves ...
2
votes
1answer
419 views

What browsers support encryption or decryption using local certificates, or smartcard readers?

I am working on a cloud-based solution and I would like to encrypt / decrypt the data locally using either a SmartCard or local Machine certificate. I'm hoping to do this in Javascript, but may ...
18
votes
3answers
804 views

NoScript: How to determine which sites/scripts to whitelist?

NoScript is a great plug-in, both for security and for ad blocking. However, I've found it's not always easy to figure out what scripts need to be permitted on certain pages, to be able to use the ...
11
votes
5answers
1k views

Solution to allow JavaScript input but prevent XSS

We have a simple Blog system that allows users to input html and JavaScript to build a blog page. I'm aware that allowing javascript open up the door to xss attacks. We do however need to allow users ...
5
votes
1answer
442 views

Access to other local files from a local HTML file

I tried this question on programmers site with no luck Do you see any reason to block a local html file from accessing another local files located in the same folder? I mean, if a user downloaded an ...
6
votes
4answers
283 views

Is flash or javascript a bigger security concern?

Many flash website whitelisting extensions for chrome (such as flashblock and flashcontrol) use javascript in order to selectively block Adobe Flash from functioning. Thus, In order to get this ...
6
votes
3answers
132 views

Are bookmarklets safe with facebook data?

I usually play mafia wars and use bookmarklet like Spockholm, Arum, etc. Can these bookmarklet get my facebook data when I run them, they usually ask to unframe the facebook page. I was just ...