AJAX May Be Considered Harmful 308
87C751 writes "Security lists are abuzz about a presentation from the 23C3 conference, which details a fundamental design flaw in Javascript. The technique, called Prototype Hijacking, allows an attacker to redefine any feature of Javascript. The paper is called 'Subverting AJAX' (pdf), and outlines a possible Web Worm that lives in the very fabric of Web 2.0 and could kill the Web as we know it."
first post (Score:5, Funny)
re: first post (Score:4, Interesting)
Further, the slashdot summary suggests that Prototyping is a design flaw in JavaScript/ECMAScript. This wrong for two reasons:
- The article doesn't mention this.
- Prototyping is not a design flaw.
Prototyping is a very useful language feature that can be used to do all sorts of things that would otherwise be cumbersome or impossible. Ruby is a prototyped language - a feature which is responsible for much of the 'magic' of Rails.The article does outline a number of Ajax related vulnerabilities, but like most vulnerabilities, they can be mitigated or avoided entirely if paid attention to - much like the SQL injections of old.
Arguing that Prototyping or Ajax makes JavaScript unsafe is fud. These are powerful language features that (like any powerful feature) can be used for evil if an injection mechanism is available.
Re: first post (Score:5, Insightful)
This is an extremely basic point in security of any kind: once the attacker is executing code inside your system, that's bad. Nevermind that fact that other limiting factors will mitigate the range of the attack (browser-only for JavaScript, account-permissions-only for other attacks). Most efforts should be made to prevent intrusion, not to limit damage after the attacker is "in".
Nothing for you to see here. Please move along. (Score:4, Funny)
The sky is falling! (Score:2, Funny)
Have you ever tried to deploy an AJAX application? (Score:5, Informative)
AJAX applications just aren't solid or stable, for the most part. We tried to integrate a number of them into our network here, and frankly each attempt went terribly. I'd like to think it was just one application vendor or AJAX toolkit that was problematic, but that wasn't the case.
We found a number of common problems with every AJAX application we tried. Just for the record, the applications included three CMS systems, a Web-based email system, two groupware systems, and three Web forums.
The first major problem with one of resource usage, on both the client-side and the server-side. Client-side, many AJAX applications consume far too much CPU time. From our investigation, it was due to the use of poor JavaScript algorithms that'd consume 100% of the CPU in some cases, for minutes on end. The applications "worked", in that they'd provide the correct result. It'd just take them far too long to get it done.
On the server-side, they'd again result in excessive CPU and RAM consumption. For one of the Webmail systems, we could only handle a fifth (yes, 20%) of what our old Perl-based system could. And that was on a quad-core Opteron system with 8 GB of RAM! The Perl-based system was on a couple of 200 MHz Pentium systems, each with 128 MB of RAM. Even after assistance from the AJAX-based Webmail system's vendor, we were only able to handle roughly 90% of the number of transactions of our older system.
The second major problem is that of usability. Many of the AJAX apps we tried didn't play well with browser tabs, for instance. Some even fucked around with text input areas, resulting in copy-and-pasting no longer working. One application even prevented the text within a text field from being highlighted! We thought these problems may be browser-specific incompatibilities, be we ran into this same problem with Firefox, Safari, Opera, and even IE6! After talking with the vendor, they admitted these were known problems, and no solutions were presently available.
The third major problem is a lack of quality. Many AJAX applications are poorly coded and poorly designed. I think the main reason for that is because it's such an unstructured technology. Even competent software developers run into problems that cannot be solved easily, and thus must resort to hackish techniques to overcome these inherent problems.
The fourth major problem was that the users hated the systems. Of the few systems we managed to roll out successfully, the users absolutely hated them. Their complaints were a combination of the above three factors. The AJAX applications would not do what the user wanted. The AJAX applications did not conform to common practices (eg. copy-and-paste, textbox text selection, etc.). The AJAX applications ran far too slowly, even on fast client machines. The AJAX applications just plain didn't work!
All of our AJAX trials were abysmal failures. That's why we're sticking with the existing Perl- and Java-based systems that we currently use. They perform far better on much fewer resources, actually do what the users want, avoid violating the most common of conventions, and they do what they're supposed to. I'm sorry to say it, but AJAX might just be the worst technology I have ever had to deal with.
Re:Have you ever tried to deploy an AJAX applicati (Score:2)
Same is with for example yahoo mail. All my friends who used the 'new improved' one, reverted to old one. Too slow and annoying.
There's more examples like that. When finally vendors understand that
Re:Have you ever tried to deploy an AJAX applicati (Score:2)
Re:Have you ever tried to deploy an AJAX applicati (Score:5, Insightful)
As for your specific case of a text field being unhighlightable, I suspect that has to do with the Ajax application using onSelectStart to disable selection within the page (sometimes as really crappy DRM, sometimes because click-and-dragging is needed for some other functionality), and not knowing how to re-enable it for the text field (which is something I, a 16-year-old, know how to do). Problems like the ones you describe are usually caused by vendor incompetence.
Ajax, by itself, can't possibly cause any of the problems you describe. All it is is a system by which Web pages can interact with the server without needing to load a new page. This means:
1. Less bandwidth is used because you don't need to load layout information for each page. Consequently, it's faster than non-Ajax applications.
2. The Back button goes to the last page, as opposed to the last action, which is a good thing for true Web applications, since the Back button usually causes tons of problems (Ever seen "DON'T PRESS THE BACK BUTTON OR YOU COULD ACCIDENTALLY PAY FOR THIS PRODUCT TWICE"?).
3. If coded to do so, the server can relegate translating raw data into a human-readable HTML layout to the client. This is usually done because the client usually has many processor cycles to spare, while the server doesn't. (This also doesn't take much processing power, and should be unnoticeable to the client)
4. You have more control over page transitions, and you can have things like "Loading..." messages while the data is being fetched from the server (as opposed to traditionally, where the only indication is "Loading..." in the browser status bar and the top right loading animation, and then, when it loads, the page goes white and the new layout is loaded.)
Those are the only differences. So, in reality, Ajax is superior in every way for Web applications, and the problems you describe are caused by bad programming practices, and would've happened whether or not they were written in Ajax.
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The Post-and-Redirect design pattern (or the use of unique once-only form ids) solves this problem in almost all cases. Only badly written web apps still suffer from it.
The rest of your points are good, though.
Re:Have you ever tried to deploy an AJAX applicati (Score:4, Insightful)
Have you missed the portion of my post where I explained exactly what Ajax was? It's just a JavaScript library that allows the page to communicate with the server without clicking a link and bringing up a new page. How does that encourage poor development?
And I have to dispute your claim that "virtually every Ajax application is problematic". I've seen plenty of places where Ajax is used effectively - Google Maps and GMail, to name two. Maybe in your experience, they are, but, as they say, the plural of "anecdote" is not "data".
Care to give examples of these "obvious and integral ways"? I have deployed real systems, and they have worked, and I haven't come across any of the problems you've mentioned.
Re:Have you ever tried to deploy an AJAX applicati (Score:5, Funny)
By enabling development to occur at all. The program that is never written has zero bugs and is therefore the perfect program.
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I'll take a stab at this. The problem is that it encourages people to write substantially more complex front-end code in javascript than was ever attempted prior to the development of AJAX. And front-end javascript is notoriously difficult to do right: there are a lot of browser incompatibilities that need workarounds, and many thin
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There's a reason Java applications seem to be, o
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The problem is that you're not listening. Go read my original post. Eight commercial AJAX products failed us. We actually tried them. We put them to use. We even got the vendor's assistance in once case. Yet these products failed. I clearly outline exactly how they fail in my original post: performance problems, usability problems, consistency problems, and so forth.
It is quite statistically possible that you were unlucky in that all eight commercial vendors you found were incompetent. Factor in the fact that Ajax is the new buzzword, so most of the vendors advertising Ajax are probably not as competent as you would like.
I have also given plenty of evidence that those companies don't know what they're doing: They've somehow managed to make an Ajax application many times slower for the client and server, as well as take up much more bandwidth, the exact opposite of wha
Re:Have you ever tried to deploy an AJAX applicati (Score:4, Informative)
You've stated quite an amount of vagueness there, sir, not to mention this confounding statement:
Very interesting, seeing has how AJAX has nothing to do with your server-side technology whatsoever. Or how about this:
Again very interesting, seeing as how AJAX itself has nothing to do with the way users interact with form elements.
It sounds to me like either 1) you're BSing, which is my actual guess, or 2) your and your team have no idea how to actually code Javascript/AJAX/whatever, and you picked crappy packages off the internet and expected them to Just Work out of the box the same as your custom built solution.
Your problems have had nothing to do AJAX; rather, they have had to do with either your lack of knowledge or your life as a Slashdot troll.
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The only difference in an "ajax applicaiton" as far as the server is concerned is that it renders XML rather than HTML. Otherwise, a GET request is a GET request.
Re:Have you ever tried to deploy an AJAX applicati (Score:4, Informative)
I'm going to call bullshit here. An ajax application is not significantly different on the server side than a regular web app. In fact, it is often easier on the server because the server only needs to render a small portion of the result for a given action rather than and entirely new page.
What does "perl based" have to do with it? You could very well have a Perl based (on the server side) AJAXy application.
Bullshit again. You are comparing AJAX with Perl/Java based systems as if there was any comparison to be made. Saying Perl based systems are better than AJAX systems is like saying roads are better than cars!
But thanks for you input anyway, Mr. Coward.
-matthew
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I'm sorry, but I have to disagree. AJAX is NOT a great technology. It's a perversion. It bends HTTP and HTML to do things they were never meant to do. And because of that, it's not really surprising that it has so many huge prob
Re:FUD (Score:5, Interesting)
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Re:FUD (Score:5, Insightful)
Look. It depends on HOW AND WHERE you use AJAX. Jeez!!! Can we please put this to bed? Yes, if you design a whole flippin site that is one page with a zillion AJAX calls, well, gee whiz! Bad idea! But, if you use your brain and use it only where it ADDS VALUE then maybe, just maybe, it's a good thing? You think? Just because beer is a good thing doesn't mean you pour it in your gas tank, use it to make Kool-Aid, or bathe in it. I am SICK (can you tell?) of people misusing technologies and then blaming the technologies! Stop it!!!
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We are talking about websites/webapplications here. The question is not whether you can and want to install it, but whether the customers/target group of that website want to/can/will install it -- and the answer
Re:The sky is falling! (Score:4, Funny)
Which hype, AJAX itself or AJAX ending the world?
Does Al Gore know anything about this?
"Considered Harmful" (Score:5, Insightful)
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Now, I know you
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After 'change' you forgot to include 'for the better' :)
C/C++ (Score:2)
stop people from using Microsoft Office (Score:2)
Nah, people really dont care/understand/know.
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I really don't see what there is this huge hatred towards Javascript. Javascript and now AJAX (which is just a method of using JavaScript) Is actually one of the best combining server and client side applications, that will work multi-browers and multi-platform. As well the band with savings can be good because you will only send the information you need once. Things like Flash, JavaApplets, Active X are good examples of a bad attempt to
Web 2.0.1 (Score:5, Funny)
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</joke>
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Greasemonkey? (Score:2, Interesting)
Re:Greasemonkey? (Score:4, Informative)
This is about the way Javascript implements object oriented programming: In Javascript you don't define classes from which objects are instantiated. In a nutshell, you create prototype objects and new objects are copies of the prototypes. The "attack" is to change existing prototypes. For example, you can add a new function to the String prototype or replace an existing function with your own implementation. Every String object then gets the new function. There is one problem with this: Cross site checks don't apply. A script from one site can't simply communicate with another site, but it can modify the prototypes that the scripts from the other site use and subvert the communication of the other script with its host.
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Re:Greasemonkey? (Score:5, Insightful)
You didn't test that and just assumed it's true I guess. But if they applied, and each page context runs in its own sandbox with its own version of String, Number, and so on, you'd sound pretty stupid right?
Try it yourself, the prototypes are NOT shared. They are not shared even among two page tabs on the same domain.
In fact not shared even among two instances of the SAME PAGE.
Embarassing, I guess, for all modded 5+ claiming this on this article.
A bit over the top... (Score:4, Insightful)
Re: (Score:2)
It's been fun intar-web! We've had some good times! Never let go!
notabug (Score:3, Insightful)
Re: (Score:2, Funny)
He's obviously been watching to much local weather forecasting lately:
"Scattered showers in the afternoon; Save the women and children!"
The Society of Hysteria really is getting to be a bit much.
KFG
Re:notabug (Score:5, Funny)
Re:notabug (Score:5, Informative)
page 3
This technique has been found by S. Di Paola and is called Prototype
Hijacking. It represents the state of the art in hijacking
techniques applied to the Javascript language.
page 6
This new kind of attack has been called AICS and has been thought by S.
Di Paola and G. Fedon and developed by S. Di Paola.
page 8
Stefano Di Paola. Senior Security Engineer of proved experience, works
since many years as an IT consultant for private and public companies.
He teaches Database Programming and Information Security at the
University of Florence. Since 1997 is a well known security expert; he
found many of the most dangerous vulnerabilities in recent releases of
MySQL and PHP. From 2004 his researches focused mainly on Web security.
Actually he is part of OWASP (Open Web Application Security Project)
team and he's the focal point of Ajax security for the Italian Chapter.
He is the creator of http://www.wisec.it/ [wisec.it]
Giorgio Fedon. Currently employed as senior security consultant and
penetration tester at Emaze Networks S.p.a, delivers code auditing,
Forensic and Log analysis, Malware Analysis and complex Penetration
Testing services to some of the most important Companies, Banks and
Public Agencies in Italy. He participated as speaker in many national
and international events talking mainly about web security and malware
obfuscation techniques. During his past job he was employed at IBM
System & Technology Group in Dublin (Ireland).
Actually he is part of Owasp (Open Web Application Security Project)
Italian Chapter.
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Re: (Score:3, Funny)
Circumventing the XSS protection of AJAX (Score:4, Insightful)
Since AJAX runs on the client side it's not possible to whitelist IPs and Referers can be spoofed.
As with every client/server app the client can never be trusted.
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In other words, if your javascript calls anything that proxies a resource, normal per-domain restrictions don't apply.
This isn't even XSS. Its just how it works ...
Wake me up when there's some REAL news :-)
Re:notabug (Score:5, Informative)
Try reading the paper before lambasting it. The stuff you saw in the slashdot article isn't in the paper. The author of the paper says things like "innovative new attack" and "next generation of server side injection." The stuff about end of the web as we know it is from the slashdot poster. The paper is quite insightful, and the author is almost blase about the whole thing. It's quite clear that he simply believes he's unearthed a new form of attack, and he's in fact quite correct.
Please get off of your soapbox. You're wrong.
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No, the author has not actually unearthed anything new; the mutability of object prototypes is a well-known and well-understood aspect of JavaScript. The potential to cause unexpected behavior by changing the prototypes of built-in objects is likewise well-known and well-understood (and has been a source of com
Re: (Score:2)
The possibility of using them to launch an attack is what he's claiming is new, and I've never heard of it before. This is something I keep up with, so I'm going to remain somewhat firm in my belief that this is an insightful paper until someone shows me prior exposition.
You missed a paragraph there (Score:2)
This technique requires the prior existence of a full-exploitable XSS hole before it can work; otherwise the script which modifies object prototypes never loads and never executes. Again, the author of this paper is simply saying, "if your site has an XSS hole I can use an XSS exploit against it". This would be akin to a physical security expert pronouncing that he can get into your house if you leave your doors and windows unlocked, and is not earth-shattering or insightful in any way; the only reason it's
Re:notabug (Score:5, Insightful)
The thing which is novel in this paper is the delivery mechanism, specifically by fundamentally replacing parts of javascript to carry attacks in what would otherwise be quite clean and legitimate code. The only parallel I can think of is the embedded-in-compiler attack that was referred to by the Guy Steele era TNHD as "the greatest hack ever," wherein the foreign code installed itself into anything compiled by said compiler, including new iterations of said compiler. (By the by, I can think of several hacks I think are better; I just mentioned the phrase because most people know to what that refers.)
And XSS is by no means new, or "fundamental flaw" of JS.
I'm not sure why you keep talking about XSS. XSS prototype overloading attacks are just his first example of something you could deploy over his new attack vector. The paper isn't about the XSS attack at all. It's not the payload he's talking about, it's the delivery mechanism. You might consider re-reading. I mean, come on, he even cites someone named "S. Di Paola" (near the top of the second column on page three of the PDF) as the person who came up with the XSS attack he uses as an example, and the XSS attack starts right after the header "advanced example". Why are you suggesting he claimed that was new?
As far as whether prototype overloading is a fundamental flaw of javascript, from the security perspective the current implementation most certainly is. There is no mechanism to identify whether a fundamental library feature has been replaced, or whose implementation you're using. There is not yet an existing mechanism by which an application can defend itself from this kind of attack; this must be defended against by the runtime environment instead, and there are not currently any runtime environments which defend against this sort of thing. Indeed, some of the JavaScript libraries I use rely on that those features are replacable (specifically prototype, moofx, behaviour and dojo, though I know of quite a few other libraries which do it too.) MooFX adds a ton of new features to fundamental things like Objects, Arrays and Strings that I use all the time.
The same mechanism Moo uses to extend things could be used to extend bad things into place. The XSS attack is just an example. It's the extension he's talking about. It wouldn't be hard to "extend" a "logging" mechanism into XMLHttpRequest; indeed I did that once as a debugging tool. What if said logging mechanism logged to a foreign server? There are a million ways to exploit this.
When XSS can occur, it's an implementation flaw of the browser and/or site, and by no means "fundamental" as it's usually fixed in the next point release or site update.
You seem to have entirely missed the point. The thing this paper describes is an attack mounted by a malicious site against later sites in the user's browsing path, not an attack mounted against a site with a flaw. This attack leverages a flaw in current browser implementations of JavaScript in such a way that there need not be a flaw in the remote site, and it is neither possible for a remote site to detect or resist such attacks.
The fundamental flaw is not in Javscript. It's in current implementations of Javascript. You are confusing mechanisms and targets. Yes, the target of this attack is other sites, but the mechanism has nothing to do with the target, and there's nothing the target can do. It's a browser-side attack.
Fundamental would mean it can't be fixed
Yes and no. It's fundamental *to* *current* *implementations* of the language, not the language itself. So yes, it cannot be fixed, *in* *current* *implementations*; it requires a minor new implementation strategy on the part of browser vendors. This will end up requiring a security patch to all browsers (and probably three to IE.)
and if you BS detectors aren't screaming by his paper, you're more gullible than you suspect.
Please re-read the paper. You seem to have missed the point.
Re:notabug (Score:4, Insightful)
Repeat after me: client-side, interpreted language.
You're loading SOURCE CODE on a machine you DO NOT CONTROL.
In other words, the fact you can "hijack" prototype methods is not a major discovery, since you can actually modify the actual *source code* itself, the classes instantiated can be replaced with other classes, variables can be read and written, instances can be destroyed and replaced.
This is what "scripting" is about. If you don't like it and you're juggling with sensitive info on the client side, there's only one option: not allow XSS by carefully validating scenarios where this may occur (such as displaying poorly sanitized customer data on public pages).
I guess some people still have some difficulty comprehending that anything in JS is subject to change on the client side.
Re:notabug (Score:4, Insightful)
A good example is writing your own proxy to fetch a site, then inject your own scripts into it before feeding it to your browser. Block ads, replace the body.onLoad() that calls a bunch of popups, rewrite all the urls, etc.
Gee, maybe I should write up a fancy paper on how I did it, say its the "latest attack vector" or some other nonsense, and pimp myself as some 133t s3cur1ty xp3rt.
prototype overloading is not special (Score:2, Informative)
I just consider this an efficient use of javascript. It's not enabling anything that couldn't be done alrea
Re: (Score:2, Insightful)
A well-travelled road (Score:2)
But, yes, there is nothing new in AJAX that causes security problems. It is not new tech, just a style of architecture. The same problems and solutions with respect to security exists for AJAX as for the underlying infrastructure. Java applets, Flash apps, "traditional" Javascripted pages, all have had their trials and tribulations in the past, and their security models are well mapped-out. The sandboxes already exist. AJAX ru
Re: (Score:3, Interesting)
If touching prototypes of built-in objects would persist across sites there simply could not have been more than one JS framework system. And nobody would have had scripting enabled...
Summary completely overhyped (Score:5, Informative)
Having skim read the article, it outlines how *if* you can execute malicious javascript for a website you can subvert the AJAX communication so that you can have man in the middle attacks etc.
However once an attacker can execute malicious javascript in the scope of the target website you're toast whether you are using AJAX or not.
I'll make a bold prediction and say that is not going to "kill the Web as we know it" contrary to what the /. article says.
Re: (Score:3, Funny)
2. ???
3. Subvert their AJAX, intercept their communications, change their content, kill the Web as we know it, and ultimately, profit!!!
FUD? (Score:2)
This statement has FUD written all over it. (or was it written in FUD?)
Re:FUD? (Score:5, Funny)
Ok, I propose we create a new programming language called FUD. Variables will be assumed to have their most sinister values and be impossible to verify.
Re: (Score:3, Funny)
Ok, I propose we create a new programming language called FUD. Variables will be assumed to have their most sinister values and be impossible to verify.
Is that language derived from brainfuck?
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Re:FUD? (Score:5, Funny)
Sadly, no. The FUD compiler was written in Javascript, and was hijacked.
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I was hoping that it wasn't totally FUD, and the result would be that the term Web 2.0 would be killed. Guess my luck isn't that good.
Horeshit.....javascript is crap but....horeshit (Score:2, Informative)
Re:Horeshit.....javascript is crap but....horeshit (Score:5, Insightful)
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It didn't use to be (apart from both of them having C-related syntax and Interweb-related hype), but it is now [mozilla.org] if you're using Firefox. For example, the following works:
They're no fun though, they left out stuff like java.io
Re:Horeshit.....javascript is crap but....horeshit (Score:5, Insightful)
Name a Turing-complete programming tool which has not seen this.
I throw in the qualifier because, other than stuff like regular expressions and SQL, which are not Turing-complete and have blissfully narrow scopes, everything else has seen javascript-acular scope creep.
Here, have an httpd written in PostScript: http://public.planetmirror.com/pub/pshttpd/ [planetmirror.com]
Perhaps not being Turing-complete is a left-handed virtue.
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I am an extremley adept programmer. I have been coding since I was 7 (in 1977) I started with Fortran (Yes 77
I could, code web pages, or whatever in assy if I wanted
When
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Re:Horeshit.....javascript is crap but....horeshit (Score:4, Insightful)
JavaScript has all the niceties of modern OO languages and more, because it's prototype-based. All that's needed is some discipline, because it also allows you to write exceptionally ugly code. Both Perl and C++ are the same way. You can drop into procedural hell any time you like. In C++, you can even resort to goto statements or drop into assembler.
In JavaScript: you can have static class methods & members, encapsulation (private methods & such), multiple layers of abstraction, and features even Java can't handle, like: multiple inheritance, closures, reflection, and dynamic typing. Not to shabby for a crappy little scripting language.
Any nice OO language (like Python, Smalltalk, Ruby) in a browser sounds wonderful... but it'll never work for very long. Do you really think that Microsoft could keep proprietary language tweaks out of their implementations? It happens with JavaScript all of the time. Netscape added proprietary features because it was THEIR language. AFAIK, that stopped as soon as it was offered up for standardization.
Microsoft has continued to make proprietary "contributions" to JavaScript. If it weren't for them, everybody's JS implementations would work together in harmony. Microsoft alters their HTML, XML, CSS, and C++ implementations in ways that prohibit cross-platform compatibility (what a surprise). They'll do the same to Python.
Crying "Wolf" (Score:3, Interesting)
Do they ever learn? All of this scaremongering is numbing the uninitiated, and when there is a real threat no one will be prepared.
Well, my BS meter pings off the scale when I see alarmist claims like "shutting down the web." How many of those claims have we all seen over the past years?
I suppose it's the 21st-century equivalent of "The World is Comming to an End!"
I consider that anyone who makes such outlandish claims should be remembered, indexed, marked, and noted. When their claims fails to come true, then we can all stand around and laugh at them and grant them Idiot Awards.
On the next episode of Days of Our Web2.0 Lives... (Score:5, Funny)
Who is this masked man known as the worm?
Why does he hate Web 2.0 so much?
Will this worm try to make us revert to Web 1.0?
And does this worm have anything to do with disappearances of Web 1.1 through Web 1.9?
This and much much more on the next epside of Days of our Web 2.0 Lives
AJAX != the web (Score:4, Insightful)
Well, considering that AJAX is used on only a tiny proportion of web sites, and often not to particularly good effect, I'd say that's a bit of a silly claim. In any case, AJAX often suffers from the same flaws as pseudo-web technologies like Flash before it: lack of bookmarkability, breaking back buttons, etc. These are far more likely to doom it than any random security flaw.
solutions (Score:3, Informative)
If 'Web 2.0' comes to be widely untrusted, it will have to change or die. This doesn't represent any new threat to the web itself. The threats are old and because of their nature have been there from the beginning and aren't going away any time soon.
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Why Ajax needs to move beyond JavaScript (Score:2)
Don't get me wrong, I think the language is "alright". The problem is it is the only choice out there.
There are many flavors of Linux and pratically everytype of appliation out there. But only one real choice for scripting on a web page.
Ajax's primary function is the ability to grab content from a web server ( or any server ) and then modify DOM of the web page you are working on.
The could be done by any
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Second, if you're unlucky enough to be using IE you do have alternatives: VBScript and,
if you have installed ActiveState, PerlScript (not that I recommend enabling a browser
with such power). I also seem to recall a Tcl plug-in back in the day.
Nevertheless, JavaScript is the de fact standard and so everybody uses it, to minimize
the potential for "foo only" websites.
Ajax IS considered harmful. (Score:4, Insightful)
The article Why Ajax Sucks (Most of the Time) [usabilityviews.com] is a nice spoof of an old article about frames. Despite being a spoof, the word 'frames' replaced by 'ajax' and little else changed, it's surprisingly accurate and nicely outlines WHY it's harmful.
Non-PDF? (Score:2)
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Ajax Can Be Harmful! (Score:2)
I don't think Comet is any better.
Seriously, can we mod the OP Flamebait? (Score:5, Informative)
I hate all this crap about "ZOMG, once I can inject javascript into a page, something else makes it totally insecure!!!"
Once someone can inject javascript onto a page, you're toast. The article itself is valid, and isn't complaining about ajax so much as prototyping (despite the title of the paper).
Meh... (Score:3, Insightful)
I'm a professional web developer, amd have been using XMLHttpRequest (ajax, if you really want) for the past two years in a large number of web applications. Having taken the time to actually carefully read (not skim) the eight pages of this document, I have only one thing to say: I want my 15 minutes back.
This is a paper about more efficient ways of being malicious, but they only work if you can be malicious in the first place.
You know what? If a malicious user can insert script to be executed for another user, I already have an unacceptable problem! I really don't care if that unacceptable problem is now 10% worse than was generally realized before.
AJAX May Be Considered Harmful (Score:3, Funny)
"Death of the Internet" yet again (Score:2)
It already died. In 1996. Bob Metcalfe [wikipedia.org] said so, didn't he?
An easy fix? (Score:2)
Re: (Score:2)
So it seems there's nothing to get excited about - you must have exploitable XSS vulnerability to begin with, so it's not the end of the internet just yet.
What's really going on here. (Score:4, Insightful)
Nobody is explaining this right.
JavaScript has a security policy. The security model is that 1) scripts can only talk to the site from which the script came, and 2) scripts can only alter documents from the site from which the script came. The security model is enforced only at a few points, notably the XMLHttpRequest object and at points where Javascript stores into the document object tree.
Other than those few enforcement points, JavaScript objects in the same browser instance can communicate freely. This offers a number of potential exploits, some of which are listed in the paper.
If the security model is tightened up, prohibiting all intercommunication between Javascript objects from different sites, "mashups" no longer work, so it's too late to tighten this up without breaking some popular sites.
This is going to be hard to fix without breaking existing programs. Javascript has a very weak concept of what's immutable. It might work to mark functions as "dirty" if changed once loaded, then forbid "new" on "dirty" functions. That would prevent changing the base instance of a class without breaking too much else, and would fix this new vulnerability. But it wouldn't fix all potential vulnerabilities in that area. As long as multiple scripts share global variables, there's going to be potential for trouble.
Maybe "https" pages should be locked down more. "Secure" pages should be single source - everything has to come from one specific domain address. No frames, no cross-site anything - one secure site per window, and no shared data with other pages whatsoever. That's a start.
Neuromancer (Score:4, Funny)
The web as I know it.... (Score:2)
Poor design security will always be a flaw (Score:3, Interesting)
At the end of the day, I verify the data I accept from the application before storing it. I don't trust anything coming from the client side. Just because it's ajax and I "think" I'm in control of the application doesn't mean that I am.
Big deal.
You still can send me options as selected if the options aren't in the list I offered you -- because I check. You can't send me invalid data because I check it for validity. That's my responsibility.
You can get me to send you something you don't have access to, because the agents that retrieve the data are running under your authority -- not as a system admin. If you don't have access to them, the data won't exist for you.
Again -- security happens at the back end. The front end is always to be considered hostile.
Re: (Score:2)
>I guess he was disappointed he can't safely store his server root passwords in his JS files.
I hope that, before that, he didn't think he could safely store his passwords in EXEs too...
Re: (Score:2, Insightful)