Javascript Comments are security risk? - javascript

During a recient PCI audit the auditor said that we had major security risks because
It was possible to download static resources from our website such as images css and javascript without prior authentication.
Our javascript had comments in it.
Personally I think that this is not a security risk at all. The images css and javascript where not dynamically created and they contained no data on our backend, our customer details and on mechanisms.
The comments within the javascript were just simply explaining what the methods in the javascript file did. Which anyone who reads JS could have found out anyway.
How does that show "information leakage"?
Are comments within javascript really a security risk?

Depending on how strict the audit, downloading images etc without authentication COULD be seen as a security risk (think diagrams, charts, graphs...).
Removing comments in the javascript is like obfuscating the code: it makes it a bit harder, but still not impossible to understand what's going on. JavaScript should be seen as enhancing-only anyway, all your security should be (duplicated) at server-side. Having anyone understand what the JS does should not be considered a risk.

It depends on the content of the commentary. Because there is no way, without human intervention, to examine the content of comments to determine whether they are risky, the most efficient way to audit this is to declare all comments in client-facing source code to be risky.
The following are examples of potentially risky comments.
// doesn't really authenticate, placeholder for when we implement it.
myServer.authenticate(user,pass);
or
// don't forget to include the length,
//the server complains if it gets NaN or undefined.
function send_stuff(stuff, length) {
...
}
or
function doSomething() {
querystring = ""
//querystring = "?TRACING_MODE=true&"
...
//print_server_trace();
}
Another example might be if you include a source code history header, someone might be able to find some security weakness by examining the kinds of bugs that have been fixed. At least, a cracker might be able to better target his attacks, if he knows which attack vectors have already been closed.
Now, all of these examples are bad practices anyway (both the comments and the code), and the best way to prevent it is by having code reviews and good programmers. The first example is particularly bad, but innocent warnings to your team mates, like the second example, or commented-out debugging code, like the third, are the kinds of security holes that could slip through the net.

Without getting into if they are a security risk or not, minify your JS on production environment, this will prevent the "information leakage" and help (in some way at least) to secure the information of your website.
regarding the security risk, I don't think JS comments are a risk at all, every website content (static) can be downloaded without authentication. (unless defined otherwise)

Not if they only reveal how the code works. Any sufficiently determined person could find that out anyway.
That said, it is probably a good idea to minify the JavaScript; not because of security, but because it will reduce download times and therefore make your site a bit more responsive.

JavaScript comments can be. depends on your logic, but certainly as it is publically available, you are giving more visibility to the workings of your code.
There are other reasons for removing this as as well, such as file size, and as a result download size.
Tools such asd JSMin can help you remove the comments and perfrom a crude obfuscation of the code.

Related

Any legitimate security concern with making JavaScript source map public?

I am using bug tracking software to report any errors that occur in a web browser but the code on my production site is minified. As a result, debugging is near impossible (variable names are changed, etc.).
I want to put a full source map file in production so I can debug these errors but have heard some concerns about privacy/security in doing this. Since minified JavaScript can be un-minifed and reverse engineered without a source map, I am wondering if this is a legitimate concern. All I can see is that it would just make that process faster.
Is there a legitimate security concern for putting a sourcemap into the public domain?
As opposed to what others are saying, there is a security aspect to it.
You are right in that it is possible to analyse (un-minify, etc.) the source without the source map too. It will never be 100% secure as you know. However, security is about capabilities and effort, and the risk that comes from these. It's about your threat model and attacker model.
A real world attacker often doesn't have unlimited resources, but has limited knowledge of your software. So while strictly speaking an obfuscated Javascript code without a source map is technically equivalent to the actual source code because it can be inspected when run on the client anyway, in the real world there is a significant difference in the effort, skill and resources needed for this.
So while I'm not at all advocating security by obscurity, and I firmly think your code should be secure against an attacker that has the source code, this will not always be the case in reality, there will be vulnerabilities, and those will be easier to discover for an attacker if source maps are available.
Only concern would be making it easier for someone to dupe your code. No security issues beyond that.

How can I obfuscate the client side source code of my ES6 / React / Redux / Electron project? [duplicate]

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I want to make a JavaScript application that's not open source, and thus I wish to learn how to can obfuscate my JS code? Is this possible?
Obfuscation:
Try YUI Compressor. It's a very popular tool, built, enhanced and maintained by the Yahoo UI team.
You may also use:
Google Closure Compiler
UglifyJS
UPDATE: This question was originally asked on 2008, and The mentioned technologies are deprecated. you can use:
terser - more information in web.dev.
Private String Data:
Keeping string values private is a different concern, and obfuscation won't really be of much benefit. Of course, by packaging up your source into a garbled, minified mess, you have a light version of security through obscurity. Most of the time, it's your user who is viewing the source, and the string values on the client are intended for their use, so that sort of private string value isn't often necessary.
If you really had a value that you never wanted a user to see, you would have a couple of options. First, you could do some kind of encryption, which is decrypted at page load. That would probably be one of the most secure options, but also a lot of work which may be unnecessary. You could probably base64 encode some string values, and that would be easier.. but someone who really wanted those string values could easily decode them. Encryption is the only way to truly prevent anyone from accessing your data, and most people find that to be more security than they need.
Sidenote:
Obfuscation in Javascript has been known to cause some bugs. The obfuscators are getting a little better about it, but many outfits decide that they see enough benefit from minifying and gzipping, and the added savings of obfuscation isn't always worth the trouble. If you're trying to protect your source, maybe you'll decide that it's worth your while, just to make your code harder to read. JSMin is a good alternative.
I'm surprised no one has mentioned Google's Closure Compiler. It doesn't just minify/compress, it analyzes to find and remove unused code, and rewrites for maximum minification. It can also do type checking and will warn about syntax errors.
JQuery recently switched from YUI Compresser to Closure Compiler, and saw a "solid improvement"
Obfuscation can never really work. For anyone who really wants to get at your code, it's just a speed bump. Worse, it keeps your users from fixing bugs (and shipping the fixes back to you), and makes it harder for you to diagnose problems in the field. Its a waste of your time and money.
Talk to a lawyer about intellectual property law and what your legal options are. "Open Source" does not mean "people can read the source". Instead, Open Source is a particular licensing model granting permission to freely use and modify your code. If you don't grant such a license then people copying your code are in violation and (in most of the world) you have legal options to stop them.
The only way you can really protect your code is to not ship it. Move the important code server-side and have your public Javascript code do Ajax calls to it.
See my full answer about obfuscators here.
You can obfuscate the javascript source all you want, but it will always be reverse-engineerable just by virtue of requiring all the source code to actually run on the client machine... the best option I can think of is having all your processing done with server-side code, and all the client code javascript does is send requests for processing to the server itself. Otherwise, anyone will always be able to keep track of all operations that the code is doing.
Someone mentioned base64 to keep strings safe. This is a terrible idea. Base64 is immediately recognizable by the types of people who would want to reverse engineer your code. The first thing they'll do is unencode it and see what it is.
There are a number of JavaScript obfuscation tools that are freely available; however, I think it's important to note that it is difficult to obfuscate JavaScript to the point where it cannot be reverse-engineered.
To that end, there are several options that I've used to some degree overtime:
YUI Compressor. Yahoo!'s JavaScript compressor does a good job of condensing the code that will improve its load time. There is a small level of obfuscation that works relatively well. Essentially, Compressor will change function names, remove white space, and modify local variables. This is what I use most often. This is an open-source Java-based tool.
JSMin is a tool written by Douglas Crockford that seeks to minify your JavaScript source. In Crockford's own words, "JSMin does not obfuscate, but it does uglify." It's primary goal is to minify the size of your source for faster loading in browsers.
Free JavaScript Obfuscator. This is a web-based tool that attempts to obfuscate your code by actually encoding it. I think that the trade-offs of its form of encoding (or obfuscation) could come at the cost of filesize; however, that's a matter of personal preference.
What i would do:
A. Troll the hacker!
This is will be in the second part my fake/obfuscated secret javascript code LAUNCHER.
The one you see in the source code.
What does this code?
loads the real code
sets a custom header
posts a custom variable
var ajax=function(a,b,d,c,e,f){
e=new FormData();
for(f in d){e.append(f,d[f]);};
c=new XMLHttpRequest();
c.open('POST',a);
c.setRequestHeader("Troll1","lol");
c.onload=b;
c.send(e);
};
window.onload=function(){
ajax('Troll.php',function(){
(new Function(atob(this.response)))()
},{'Troll2':'lol'});
}
B. Obfuscate the code a little
What is that?
thats the same code as above in base64
this is not the SECRET javascript code
(new Function(atob('dmFyIGFqYXg9ZnVuY3Rpb24oYSxiLGQsYyxlLGYpe2U9bmV3IEZvcm1EYXRhKCk7Zm9yKGYgaW4gZCl7ZS5hcHBlbmQoZixkW2ZdKTt9O2M9bmV3IFhNTEh0dHBSZXF1ZXN0KCk7Yy5vcGVuKCdQT1NUJyxhKTtjLnNldFJlcXVlc3RIZWFkZXIoIlRyb2xsMSIsImxvbCIpO2Mub25sb2FkPWI7Yy5zZW5kKGUpO307d2luZG93Lm9ubG9hZD1mdW5jdGlvbigpe2FqYXgoJ1Ryb2xsLnBocCcsZnVuY3Rpb24oKXsgKG5ldyBGdW5jdGlvbihhdG9iKHRoaXMucmVzcG9uc2UpKSkoKX0seydUcm9sbDInOidsb2wnfSk7fQ==')))()
C Create a hard to display php file with the real code inside
What does this php code?
Checks for the right referrer (domain/dir/code of your launcher)
Checks for the custom HEADER
Checks for the custom POST variable
If everything is ok it will show you the right code else a fake code or ban ip, close page.. whatever.
<?php
$t1=apache_request_headers();
if(base64_encode($_SERVER['HTTP_REFERER'])=='aHR0cDovL2hlcmUuaXMvbXkvbGF1bmNoZXIuaHRtbA=='&&$_POST['Troll2']=='lol'&&$t1['Troll1']='lol'){
echo 'ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChkb2N1bWVudC5jcmVhdGVFbGVtZW50KCdkaXYnKSkuaW5uZXJUZXh0PSdBd2Vzb21lJzsNCg==';//here is the SECRET javascript code
}else{
echo 'd2luZG93Lm9wZW4oJycsICdfc2VsZicsICcnKTt3aW5kb3cuY2xvc2UoKTs=';
};
?>
base64 referrer = http://here.is/my/launcher.html
SECRET javascript = document.body.appendChild(document.createElement('div')).innerText='Awesome';
FAKE = window.open('', '_self', '');window.close();
Now .. if you define event handlers in the SECRET javascript it's probably accessible.. you need to define them outside with the launchcode and pointing to a nested SECRET function.
SO... is there a easy wayto get the code?
document.body.appendChild(document.createElement('div')).innerText='Awesome';
I'm not sure if this works but i'm using chrome and checked Elements,Resources,Network,Sources,Timeline,Profiles,Audits but i didn't find the line above.
note1: if u open the Troll.php url from Inspect element->network in chrome you get the fake code.
note2: the whole code is written for modern browsers. polyfill needs alot more code.
EDIT
launcher.html
<!doctype html><html><head><meta charset="utf-8"><title></title><script src="data:application/javascript;base64,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"></script></head><body></body></html>
Troll.php
<?php $t1=apache_request_headers();if(/*base64_encode($_SERVER['HTTP_REFERER'])=='PUT THE LAUNCHER REFERER HERE'&&*/$_POST['Troll2']=='lol'&&$t1['Troll1']='lol'){echo 'ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChkb2N1bWVudC5jcmVhdGVFbGVtZW50KCdkaXYnKSkuaW5uZXJUZXh0PSdBd2Vzb21lJzsNCg==';}else{echo 'd2luZG93Lm9wZW4oJycsICdfc2VsZicsICcnKTt3aW5kb3cuY2xvc2UoKTs=';}; ?>
The problem with interpreted languages, is that you send the source to get them working (unless you have a compiler to bytecode, but then again, it is quite trivial to decompile).
So, if you don't want to sacrifice performance, you can only act on variable and function names, eg. replacing them with a, b... aa, ab... or a101, a102, etc. And, of course, remove as much space/newlines as you can (that's what so called JS compressors do).
Obfuscating strings will have a performance hit, if you have to encrypt them and decrypt them in real time. Plus a JS debugger can show the final values...
Try JScrambler. I gave it a spin recently and was impressed by it.
It provides a set of templates for obfuscation with predefined settings for those who don't care much about the details and just want to get it done quickly. You can also create custom obfuscation by choosing whatever transformations/techniques you want.
Contrary to most of the other answers I suggest against YUI Compressor; you should use Google Closure.
Not much because it compresses more, but mostly because it will catch javascript errors such as a = [1,2,3,]; which make IE go haywire.
I can recommend JavaScript Utility by Patrick J. O'Neil. It can obfuscate/compact and compress and it seems to be pretty good at these. That said, I never tried integrating it in a build script of any kind.
As for obfuscating vs. minifying - I am not a big fan of the former. It makes debugging impossible (Error at line 1... "wait, there is only one line") and they always take time to unpack. But if you need to... well.
A non-open-source Javascript-based application is fairly silly. Javascript is a client-side interpreted language.. Obfuscation isn't much protection..
JS obfuscation is usually done to reduce the size of the script, rather than "protect" it. If you are in a situation where you don't want your code to be public, Javascript isn't the right language..
There are plenty of tools around, but most have the word "compressor" (or "minifier") in its name for a reason..
You can't secure client side code: just press F12 on Google Chrome, pause javascript execution and you will get all strings, even those encrypted. Beautify it and rename variables and you will get almost the original code.
If you're writing server side javascript (i.e. NodeJS) is afraid of someone hacking into your server and want to make the hacker work more difficult, giving you more time to get your access back, then use javacript compilers:
You need to use Closure Compiler on Advanced Compilation, as it's the only tool that renames all your variables, even if those are used in multiple files/modules. But it just have a problem: it only work if you write in it's coding style.
I would suggest first minify with something like YUI Compressor, and then convert all string and numbers to HEX Values using something like http://www.javascriptobfuscator.com/
With this, the code would be rendered near impossible to understand and I think at this Stage it will take more time for a Hacker to re-enact your code than actually if he re-wrote from scratch. Rewriting and Cloning is what you cant actually stop. After all we are free-people !
Try this tool Javascript Obfuscator
I used it on my HTML5 game not only it reduced it size from 950KB to 150 but also made the source code unreadable closure compilers and minifiers are reversable I personally dont know how to reverse this obfuscation.
Dean Edward's Packer is an excellent obfuscator, though it primarily obfuscates the code, not any string elements you may have within your code.
See: Online Javascript Compression Tool and select Packer (Dean Edwards) from the dropdown
I'm under the impression that some enterprises (e.g.: JackBe) put encrypted JavaScript code inside *.gif files, rather than JS files, as an additional measure of obfuscation.
I've been using Jasob for years and it is hands down the best obfuscator out there.
It has an advanced UI but is still intuitive and easy to use.
It will also handle HTML and CSS files.
The best way to use it is to prefix all of your private variables with something like an underscore, then use the sort feature to group them all together and check them off as targets for obfuscation.
Users can still view your source, but it's much more difficult to decipher when your private variables are converted from something like _sUserPreferredNickName to a.
The engine will automatically tally up the number of targeted variables and prioritize them to get the maximum compression.
I don't work for Jasob and I get nothing out of promoting them, just offering some friendly advice.
The downside is that it's not free and is a little pricey, but still worth it when stacked against alternatives - the 'free' options don't even come close.
Have you tried Bananascript? It produces highly compressed and completely unreadable code.
I am using Closure-Compiler utility for the java-script obfuscation. It minifies the code and has more options for obfuscation.
This utility is available at Google code at below URL:
Closure Tools
But now a days I am hearing much of UglifyJS. You can find various comparison between Closure Compiler and UglifyJS in which Uglify seems to be a winner.
UglifyJS: A Fast New JavaScript Compressor For Node.js That’s On Par With Closure
Soon I would give chance to UglifyJS.
As a JavaScript/HTML/CSS obfuscator/compressor you can also try Patu Digua.
You definitely should consider taking a look at Obfuscriptor.
I goes beyond the typical Javascript minifying tricks we've seen from other tools such as YUI Compressor or Google Closure.
The obfuscated code looks more like encrypted. Unlike anything I've seen before.
I've used this in the past, and it does a good job. It's not free, but you should definitely take a look.
JavaScript Obfuscator & Encoder

Javascript library: to obfuscate or not to obfuscate - that is the question [closed]

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I need to write a GUI related javascript library. It will give my website a bit of an edge (in terms of functionality I can offer) - up until my competitors play with it long enough to figure out how to write it by themselves (or finally hack the downloaded script). I can accept the fact that it will be emulated over time - thats par for the course (its part of business). I just want to have a few months breathing space where people go "Wow - how the f*** did they do that?" - which gives me a few months of free publicity and some momentum to move onto other things.
To be clear, I am not even concerned about hard core hackers who will still hack the source - thats a losing battle not worth fighting (and in any case I accept that my code is not "so precious"). However, what I cannot bear, is the idea of effectively, simply handing over all the hard work that would have gone into the library to my competitors, by using plain javascript that anyone can download and use. If someone is going to use what I have worked on, then I sure as hell don't want to simply hand it over to them - I want them to work hard at decoding it. If they can decode it, they deserve to have the code (they'll most likely find out they could have written better code themselves - they just didn't have the business sense to put all the [plain vanilla] components in that particular order) - So, I'm not claiming that no one could have written this (which would be a preposterous claim in any case) - but rather, what I am saying is that no one (up to now) has made the functionality I am talking about, available to this particular industry - and I (thinking as an entrepreneur rather than a geek/coder), want to milk it for all its worth, while it lasts i.e until it (inevitably) gets hacked.
It is an established fact that not one website in the industry I am "attacking" has this functionality, so the value of such a library is undeniable and is not up for discussion (i.e. thats not what I'm asking here).
What I am seeking to find out are the pros and cons of obfuscating a javascript library, so that I can come to a final decision.
Two of my biggest concerns are debugging, and subtle errors that may be introduced by the obfuscator.
I would like to know:
How can I manage those risks (being able to debug faulty code, ensuring/minimizing against obfuscation errors)
Are there any good quality industry standard obfuscators you can recommend (preferably something you use yourself).
What are your experiences of using obfuscated code in a production environment?
If they can decode it, they deserve to have the code (they'll most likely find out they could have written better code themselves - they just didn't have the business sense to put all the [plain vanilla] components in that particular order).
So really, you're trying to solve a business issue with technical measures.
Anybody worth his salt as a Javascript programmer should be able to recreate whatever you do pretty easily by just looking at the product itself, no code needed. It's not like you're inventing some new magical thing never seen before, you're just putting pieces together in a new way, as you admit yourself. It's just Javascript.
Even if you obfuscate the script, it'll still run as-is, competitors could just take it and run with it. A few customizations shouldn't be too hard even with obfuscated code.
In your niche business, you'll probably notice pretty quickly if somebody "stole" your script. If that happens, it's a legal issue. If your competitors want to be in the clear legally, they'll have to rewrite the script from scratch anyway, which will automatically buy you some time.
If your competitors are not technically able to copy your product without outright stealing the code, it won't make a difference whether the code is in the clear or obfuscated.
While you can go down the long, perilous road of obfuscators, you generally don't see them used on real, production applications for the simple reason that they don't really do much. You'll notice that Google apps, which is really a whole heap of proprietary and very valuable JavaScript when you get down to it, is only really minimized and not obfuscated, though the way minimizers work now, they are as good as obfuscated. You really need to know what you're doing to extract the meaning from them, but the determined ones will succeed.
The other problem is that obfuscated code must work, and if it works, people can just rip it wholesale, not understanding much of it, and use it as they see fit in that form. Sure, they can't modify it directly, but it isn't hard to layer on some patches that re-implement parts they don't like without having to get in too deep. That is simply the nature of JavaScript.
The reason Google and the like aren't suffering from a rash of cut-and-paste competitors is because the JavaScript is only part of the package. In order to have any degree of control over how and where these things are used, a large component needs to be server-based. The good news is you can leverage things like Node.js to make it fairly easy to split client and server code without having to re-implement parts in a completely different language.
What you might want to investigate is not so much obfuscating, but splitting up your application into parts that can be loaded on-demand from some kind of service, and as these parts can be highly inter-dependent and mostly non-functional without this core server, you can have a larger degree of control over when and where this library is used.
You can see elements of this in how Google is moving to a meta-library which simply serves as a loader for their other libraries. This is a step towards unifying the load calls for Google Apps, Google AdSense, Google Maps, Google Adwords and so forth.
If you wanted to be a little clever, you can be like Google Maps and add a poison pill your JavaScript libraries as they are served dynamically so that they only operate in a particular subdomain. This requires generating them on an as-needed basis, and while it can always be removed with sufficient expertise, it prevents wholesale copy-paste usage of your JavaScript files. To insert a clever call that validates document.href is not hard, and to find all these instances in an aggressively minimized file would be especially infuriating and probably not worth the effort.
Javascript obfuscation facts:
No one can offer a 100% crack free javascript obfuscation. This means that with time and knowledge every obfuscation can be "undone".
Minify != obfuscation: When you minify your objective is: reduce code size. Minified code looks completly different and its much more complex to read (hint:jsbeautifier.com). Obfucation has a completly different objective: to protect the code. The transformations used try to protect Obfuscated code from debugging and eavesdropping. Obfuscation can even produce a even bigger version of the original code which is completely contrary to the objectives of minification.
Obfuscation != encryption - This one is obvious but its common mistake people make.
Obfuscation should make debugging much much harder, its one of it objectives. So if it is done correctly you can expect to loose a lot of time trying to debug obfuscated code.That said, if it is done correctly the introduction of new errors is a rare issue and you can easily find if it is an obfuscation error by temporarily replacing the code with non obfuscated code.
Obfuscation is NOT a waste of time - Its a tool. If used correctly you can make others waste lots of time ;)
Javascript obfuscation fiction: ( I will skip this section ;) )
Answer to Q2 - Sugested obfuscation tools:
For an extensive list of javascript obfuscator: malwareguru.org. My personal choice is jscrambler.com.
Answer to Q3 - experiences of using obfuscated code
To date no new bugs introduced by obfuscation
Much better client retention. They must come to the source to get the source;)
Occasional false positives reported by some anti-virus tools. Can be tested before deploying any new code using a tool like Virustotal.com
Standard answer to obfuscation questions: Is using an obfuscator enough to secure my JavaScript code?
IMO, it's a waste of time. If the competitors can understand your code in the clear (assuming it's anything over a few thousand lines...), they should have no trouble deobfuscating it.
How can I manage those risks (being
able to debug faulty code,
ensuring/minimizing against
obfuscation errors)
Obfuscation will cause more bugs, you can manage them by spending the time to debug them. It's up to the person who wrote the obfuscation (be it you or someone else), ultimately it will just waste lots of time.
What are your experiences of using
obfuscated code in a production
environment?
Being completely bypassed by side channel attacks, replay attacks, etc.
Bugs.
Google's Closure Complier obfuscates your code after you finish writing it. That is, write your code, run it through the compiler, and publish the optimized (and obfuscated) js.
You do need to be careful if your using external js that interfaces with the lib though because it changes the names of your objects so you can't tell what is what.
Automatic full-code obfuscation is so far only available in the Closure Compiler's Advanced mode.
Code compiled with Closure Advanced mode is almost impossible to reverse-engineer, even passing through a beautifier, as the entire code base (includinhg the library) is obfuscated. It is also 25% small on average.
JavaScript code that is merely minified (YUI Compressor, Uglify etc.) is easy to reverse-engineer after passing through a beautifier.
If you use a JavaScript library, consider Dojo Toolkit which is compatible (after minor modifications) with the Closure Compiler's Advanced mode compilation.
http://dojo-toolkit.33424.n3.nabble.com/file/n2636749/Using_the_Dojo_Toolkit_with_the_Closure_Compiler.pdf?by-user=t
You could adopt an open-source business model and license your scripts with the GPL or Creative Commons BY-NC-ND or similar
While obfuscation in general is a bad thing, IMHO, with Javascript, the story is a little different. The idea is not to obfuscate the Javascript itself but to produce shorter code length (bandwidth is expensive, and that first-time users may just be pissed off waiting for your Javascript to load the first time). Initially called minification (with programs such as minify), it has evolved quite a bit and now a full compiler is available, such as YUI compiler and Google Closure Compiler. Such compiler performs static checking (which is a good thing, but only if you follow the rules of the compiler), minification (replace that long variable name with 'ab' for example), and many other optimization techniques. At the end, what you got is the best of both worlds, coding in non-compiled code, and deploying compiled (, minified, and obfuscated) code. Unfortunately, you would of course need to test it more extensively as well.
The truth is obfuscator or not, any programmer worth his salt could reproduce whatever it is you did in about as much time as it took you. If they stole what you did you could sue them. So bottom line from the business point of view is that you have, from the moment you publish, roughly the same amount of time it took you to implement your design until a competitor catches up. Period. That's all the head start you get. The rest is you innovating faster than your competitors and marketing it at least as well as they do.
Write your web site in flash, or better yet in Silverlight. This will give your company unmatched GUI, that your competitors will be salivating about. But compiled nature of flash/dotnet will not allow them easily pick into your code. It's a win/win situation for you ;)

Is using an obfuscator enough to secure my JavaScript code?

I'm working on building a development tool that is written in JavaScript.
This will not be an open source project and will be sold (hopefully) as a commercial product.
I'm looking for the best way to protect my investment. Is using an obfuscator (code mangler) enough to reasonably secure the code?
Are there other alternatives that I am not aware of?
(I'm not sure if obfuscator is the right word, it's one of the apps that takes your code and makes it very unreadable.)
I'm going to tell you a secret. Once you understand it, you'll feel a lot better about the fact that Javascript obfuscation is only really useful for saving bandwidth when sending scripts over the wire.
Your source-code is not worth stealing.
I know this comes as a shock to the ego, but I can say this confidently without ever having seen a line of code you've written because outside the very few realms of development where serious magic happens, it's true of all source-code.
Say, tomorrow, someone dumped a pile of DVDs on your doorstep containing the source code for Windows Vista. What would you be able to do with it? Sure, you could compile it and give away copies, but that's just one step more effort than copying the retail version. You could painstakingly find and remove the license-checking code, but that's something some bright kid has already done to the binaries. Replace the logo and graphics, pretend you wrote it yourself and market it as "Vicrosoft Mista"? You'll get caught.
You could spend an enormous amount of time reading the code, trying to understand it and truly "stealing the intellectual property" that Microsoft invested in developing the product. But you'd be disappointed. You'd find the code was a long series of mundane decisions, made one after the other. Some would be smarter than you could think of. Some would leave you shaking your head wondering what kind of monkeys they're hiring over there. Most would just make you shrug and say "yeah, that's how you do that."
In the process you'll learn a lot about writing operating systems, but that's not going to hurt Microsoft.
Replace "Vista" with "Leopard" and the above paragraphs don't change one bit. It's not Microsoft, it's software. Half the people on this site could probably develop a Stack Overflow clone, with or without looking at the source of this site. They just haven't. The source-code of Firefox and WebKit are out there for anyone to read. Now go write your own browser from scratch. See you in a few years.
Software development is an investment of time. It's utter hubris to imagine that what you're doing is so special that nobody could clone it without looking at your source, or even that it would make their job that much easier without an actionable (and easily detectable) amount of cut and paste.
I deeply disagree with most answers above.
It's true that every software can be stolen despite of obfuscation but, at least, it makes harder to extract and reuse individual parts of the software and that is the point.
Maybe it's cheaper and less risky to use an obfuscation than leaving the code open and fighting at court after somebody stole the best parts of our software and made dangerous concurrency.
Unobfuscated code whispers:
Come on, analyze me, reuse me. Maybe you could make a better software using me.
Obfuscated code says:
Go away dude. It's cheaper to use your own ideas than trying to crack me.
You are going to be fighting a losing battle if you try to obfuscate your code in the hopes of someone not stealing it. You may stop the casual browser from getting at it, but someone dedicated would almost certainly be able to overcome any measure you use.
In the past I have seen people do several things:
Paste a lot of whitespace at the top of the page with a message telling people that the code is unavailable, when in actuality you just need to scroll down a few pages to get at it.
Running it through an encoder of some kind, this is so so useful as it can just be run through the decoder.
Another method is to reduce variable names to one character and remove whitespace (this is also an efficiency thing).
There are many other methods.
In the end, your efforts are only likely to stop the casual browser from seeing your stuff. If someone dedicated comes along then there is not much you will be able to do. You will have to live with this.
My advice would be to make a really awesome product that attracts the most people and beat off any competition by having the best product/service/community and not the most obfuscated code.
You're always faced with the fact that any user that comes to your webpage will download some working version of your Javascript source. They will have the source code. Obfuscating it may make it very difficult to be reused by someone with the intent to steal your hard work. However, in many cases someone can even reuse the obfuscated source! Or in the worst case they can unravel it by hand and eventually comprehend it.
An example of a situation like yours might be Google Maps. The Javascript source is clearly obfuscated. However, for really private/sensitive logic they push the data to the server and have the server process that information using XMLHttpRequests (AJAX). With this design you have the important parts on the server side, much more tightly controlled.
That's probably about the best you can do. Just be aware that anybody with enough dedication, can probably de-obfuscate your program. Just make sure you're comfortable with that before embarking on your project. I think the biggest problem with this would be to control who's using it on their site. If somebody goes to a site with your code on it, and likes what it does, it doesn't matter that they don't understand what the code does, or can't read it, when they can just copy the code, and use it on their own site.
A obfuscator won't help you at all if someone wants to figure out the code. The code still exists on the client machine and they can grab a copy of it and study it at their leisure.
There is simply no way to hide code written in Javascript since the source code has to be handed to the browser for execution.
If you want to hide your code, you have the following options:
1) Use an environment where compiled code (not source) is downloaded to the client, e.g. Flash or Silverlight. I'm not even sure that's foolproof, but it's certainly much better than Javascript.
2) Have a back end on the server side that does the work and a thin client that just makes requests to the server.
I'd say yes, it's enough if you also make sure than you compress the code as well using a tool like Dean Edward's Packer or similar. If you think about what is possible with tools like .NET Reflector in terms of reverse engineering compiled code / IL in .NET, you realize that there's nothing you can do to completely protect your investment.
On the other hand, remember that folks who release their source code also seem to make do quite nicely anyway - it's their experience that people want more than their intellectual property.
code obfuscator is enough for something that needs minimal protection, but I think it will definitely not enough to really protect you. if you are patient you can realy de-mangle the whole thing.. and i'm sure there are programs to do it for you.
That being said, you can't stop anyone from pirating your stuff because they'll eventually will break any kind of protection you create anyway. and it is espcially easy in scripted language where the code is not compiled.
If you are using some other language, maybe java or .NET, You can try doing things like "calling home" to verify that a license number matches a given url. Which works if you your app is some sort of online app that is going to be connected online all the time. But having access to the source, people can easily bypass that part.
In short, javascript is a poor choice for what you are doing.
A step up from what you are doing is maybe using a webservice backend to get your data. Let the webservice handle the authentication/verification process. Requires a bit of work to make sure it is bulletproof, but it might work
If this is for a website, which by its very nature puts viewing of its code one menu click away, is there really any reason to hide anything? If someone wants to steal your code they will most likely go through the effort of making even the most mangled code human readable. Look at commercial websites, they don't obfuscate their code, and no one goes out and steals code from the google apps. If you are really worried about code theft, I would argue for writing it in some other compiled language. (which does of course destroy the whole webapp thing...) Even then, you aren't totally safe, there are many de-compilers out there.
So really, there is no way to do what you want in the face of anyone with sufficient motivation.

How do you add a JavaScript widget to a Wordpress.com hosted blog?

I've got a site that provides blog-friendly widgets via JavaScript. These work fine in most circumstances, including self-hosted Wordpress blogs. With blogs hosted at Wordpress.com, however, JavaScript isn't allowed in sidebar text modules. Has anyone seen a workaround for this limitation?
you could always petition wp to add your widget to their 'approved' list, but who knows how long that would take. you're talking about a way to circumvent the rules they have in place about posting arbitrary script. myspace javascript exploits in particular have increased awareness of the possibility of such workarounds, so you might have a tough time getting around the restrictions - however, here's a classic ones to try:
put the javascript in a weird place, like anywhere that executes a URL. for instance:
<div style="background:url('javascript:alert(this);');" />
sometimes the word 'javascript' gets cut out, but occasionally you can sneak it through as java\nscript, or something similar.
sometimes quotes get stripped out - try String.fromCharCode(34) to get around that. Also, in general, using eval("codepart1" + "codepart2") to get around restricted words or characters.
sneaking in javascript is a tricky business, mostly utilizing unorthodox (possibly un-documented) browser behavior in order to execute arbitrary javascript on a page. Welcome to hacking.
From the official WordPress.com FAQ:
Javascript can be used for malicious purposes and while what you want to do is okay it does not mean all javascript will be okay.
It goes on to remind the reader that both MySpace and LiveJournal had been affected by malicious Javascript and, therefore, will not be permitted (as it may be exploited by users with poor intentions). They can't risk it with amazingly large sites (think I Can Has Cheezburger, Anderson Cooper 360, Fox, etc.).
If you think you have Javascript that would benefit WordPress.com you can contact them directly.
There is not work around for it. Wordpress does not currently support Javascript. Sorry.
Just find a good site about XSS if You really need that js to work. But if it works for You it works for anybody, and You post a tutorian on how to do an XSS attack on Your page with posts or comments.
reference:
http://ha.ckers.org/xss.html

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