Angular 1.x Banned from Firefox Addons

https://github.com/mozilla/addons-linter/issues/1000

by secmax • 10 years ago

384 195 10 years ago

github.com

smrtinsert• 10 years ago

My information is that Google stopped supporting angular 1.x months ago. It is now a community driven project.

I totally missed this - was there a notice of this posted somewhere?

wnevets3• 10 years ago

Yeah that doesn't sound true at all.

mlent• 10 years ago

Was recently at an angular conference -- they said they would continue to support it until the _majority_ of the community had made the switch. That's so far from happening, I imagine they'll be supporting it for years.

vonklaus• 10 years ago

based on that statement and others my read is basically:

We know a lot of important people and they gave us information you don't have, to which we have made business decisions that affect you that we didn't communicate. Did we tell you? no. Now that you know, are we going to elaborate? nope. trust us, our people on the inside will be proven correct soon enough, so you can thank us later.

Narretz• 10 years ago

This is not correct. Development of 1.x is still very much under Google's control.

secmax3• 10 years ago

I am really worried about the security implications for addons like bitwarden, if mozilla is right about this. I hope that competent people will take a close look.

viach• 10 years ago

Nice extension marketing

phs2501• 10 years ago

So someone found some sort of vulnerability in Angular 1, told Mozilla about it, but told them not to tell the Angular team?

What is going on here?

TD-Linux• 10 years ago

It is possible that the researcher also secretly shared the results with Google, but then nothing happened?

pestaa• 10 years ago

As claimed in the comments, Angular 1 is now community driven instead of officially supported by Google.

vladimir-y5• 10 years ago

nothing happened

On the contrary - they reacted removing sandbox completely giving up handling sandbox bypassing snippets, the problem is in the design of the framework and it can't be just fixed.

nathancahill5• 10 years ago

It's possible that the vulnerability only effects Angular running in Firefox addons, and not the general web. Mozilla takes an aggressive stance on what they allow in vetted browser extensions, as they should.

JS in addons runs in a different, more privileged environment than normal web pages, and isn't restricted by things like same-origin (although this is improving with Firefox's new extension APIs). Any project the size of Angular is bound to have security issues when run outside of the environment it was designed for.

Gigablah• 10 years ago

In other words, the vulnerability is with Firefox instead of Angular?

AgentME29• 10 years ago

The vulnerability specifically has to do with Angular being used in extensions where the extension has more privileges than the webpage it's affecting. Judging by http://www.slideshare.net/x00mario/an-abusive-relationship-w..., the issue has to do with a general design feature of Angular: it runs eval-like functions on text within the page DOM. Angular simply isn't built for the page DOM is controlled by an attacker (ie. Angular is running in a higher-privilege extension, and the webpage controls the DOM and wants to inject code into the higher-privilege extension). Angular has band-aids over a few specific ways that this can be taken advantage of, but it's extremely difficult to make bullet-proof (as blacklisting strategies often are) and it's not an issue that affects regular non-extension web pages.

vladimir-y5• 10 years ago

It's not the "some sort of vulnerability", it's a critical vulnerability in the design of the Angular v1, a long known vulnerability in fact.

codedokode8• 10 years ago

This "vulnerability" can be only exploited in specific cases when Angular is used in an unintended way - for example, injected in a web page from extension context in Firefox (which is wrong anyway because it would conflict with scripts on the page).

I tried to understand whether the same is possible in Chrome - injected scripts there have less privileges and use some form of isolation - but the manual [1] doesn't give a clear answer. The injected (and exploited) content script has lower privileges than an extension but has some API methods not available to scripts on a page. For example it can send messages to an extension and it could be exploited too.

But generally Chrome extension architecture provides more isolation and looks more secure especially when extensions are written by not very experienced developers.

[1] https://developer.chrome.com/extensions/content_scripts

UPD: Firefox uses the same security model for its web extensions as Chrome so both browsers are equally vulnerable.

tiglionabbit• 10 years ago

The explanation is in the issue thread now. If you have Angular running in an extension, if it sees Angular tags in the page you're viewing, it could execute them with the elevated permissions of the extension instead of the permissions of the page.

encoderer2• 10 years ago

Bitwarden is a password manager? And their engineer is asking, after being told a hint of serious security issues in their framework, to just forget about it and let them publish?

That's an interesting approach.

capote• 10 years ago

It is strange. On the other hand there's something suspicious here. Some things clearly aren't being communicated properly.

FireBeyond• 10 years ago

Yeah, definitely odd.

"We banned any package containing Angular 1.x. We received a security report. One that we were asked not to share with you, one that we didn't even mention, we just went ahead and implemented the ban, didn't tell anybody."

xxkylexx4• 10 years ago

No, the engineer is asking for more information so that he can determine if the application is truly affected by some unpublished Angular vulnerability or if Mozilla is just being too aggressive with their ban hammer because someone said "Angular 1.x was no longer being officially supported", which is false.

martey3• 10 years ago

I think encoderer was referring to https://github.com/mozilla/addons-linter/issues/1000#issueco..., where the engineer asks, "Is there any possible way for us to get around this ban?"

nathancahill5• 10 years ago

Title should by "Angular 1.x Banned from Firefox Addons"

sctb• 10 years ago

Thank you, we've updated the title from “Angular 1.x Ban”.

yc-kraln• 10 years ago

"we were not able to report them to angular as the security researcher who found them asked us to not share them."

Nice.

moron4hire2• 10 years ago

I read that and said a literal WTF. How is it at all acceptable to honor such a request? What possible good reason could there be?

Unless the discloser was the US Government and the request was actually a court order. But this seems ludicrous. If they require secrecy around the exploit, they wouldn't have disclosed it to Mozilla at all.

Jare3• 10 years ago

Mozilla is probably unable to disclose not just the vulnerability, but other surrounding info they may have been provided, including which other parties have received that info. They are not saying the Angular team is unaware of the problem, right? Only that they themselves are not the ones reporting it.

If you don't honor such request without a VERY STRONG reason, nobody in their right mind will ever disclose anything to you ever again. Right now we don't and can't know if such a strong reason exists.

jMyles2• 10 years ago

Unless the discloser was the US Government and the request was actually a court order.

If this were the case, I think it's actually the best reason to disregard the request of the discloser and disclose, as it's now in the public interest (ie, closing a possible backdoor being used to surveil dissidents, etc), not merely part of a private agreement.

But yeah, if mozilla signed an NDA on this, that seems like it was a bad move from the get-go.

threatofrain• 10 years ago

Mozilla is definitely in a position to reject NDA protected security information, but then they wouldn't have been privy to the security information which a researcher was conditionally offering.

Would it be better to reject the information outright? Or would you suggest that Mozilla make agreements in bad faith, deceitfully agreeing to terms they don't intend to honor?

xorcist• 10 years ago

I have no idea if that is the case here, but it is completely normal that some vulnerabilities have a set disclosure date to allow for coordinated responses. You can either get the information early but under non-disclosure, or along with everyone else. Most people play by these rules (with a few notable exceptions).

BHSPitMonkey2• 10 years ago

If there is some permutation of JavaScript statements (library or otherwise) that displays a security vulnerability for the user, isn't that the browser's fault and not the application's? And isn't library detection just a hacky substitute for an actual fix of said fault?

AgentME29• 10 years ago

It's not the browser's fault if an extension has a vulnerability which gives away the capabilities the extension was given. It would be the browser's fault if the extension had a vulnerability which somehow managed to give away more permissions than the extension was given in the first place.

In this specific case, Angular runs eval-like functions on HTML in the DOM. The DOM can be controlled by the webpage. If Angular is running in a higher-privilege extension, then the webpage can put code in the DOM and let Angular execute it from within the extension. This seems to be a fundamental part of Angular 1.x's design. It just isn't built for this use case.

BHSPitMonkey2• 10 years ago

That makes sense, thanks.

Jare3• 10 years ago

The extension has access to certain information provided by the user and the browser. Due to a vulnerability, that information is no longer secure, and may be used in ways that the user of the extension does not expect nor has approved. The platform holder treats vulnerable extensions as if they were effectively malware, and bans them.

Hard to go deeper without further information, but it makes sense to me.

ggregoire• 10 years ago

The banned version is the 1.5.8. Could the following announce be related?

Angular 1.6 - Expression Sandbox Removal: https://angularjs.blogspot.mx/2016/09/angular-16-expression-...

wnevets3• 10 years ago

removing the sandbox just removes the illusion of being protected.

vladimir-y5• 10 years ago

Correct, now it should be clear for all that Angular v1 is dangerous thing by design and it should not be used at all. Most likely a lot of not very experienced developers do for example $watch on value provided by the user input and that's a 100% XSS vulnerability since $watch does evaluate value if that was a string. And $watch is just a one example, there is a list of methods that do expressions evaluation.

AgentME29• 10 years ago

Some examples of issues with the old sandbox can be found here: http://www.slideshare.net/x00mario/an-abusive-relationship-w...

The expression sandbox was not secure (and would be extremely difficult and heavily bloat the size of Angular to secure) and was not intended to be secure. It only blacklisted specific known attacks. As your link says, they removed it because people kept thinking it was a security feature they could rely on.

Angular runs eval on the page DOM. This isn't secure when the page DOM is controlled by an attacker (such as a webpage trying to elevate into an extension's privileges). Angular 1.x is the wrong tool to use within page extensions.

supersan2• 10 years ago

Angular 1.x is still quite being actively developed and it will be many years before it will become unsupported. I'm sure if they report the vulnerability it would be fixed instantly seeing the amount of activity on github.

AgentME29• 10 years ago

The issue is a fundamental part of Angular 1.x's design. It runs eval on text within the page DOM. This isn't secure within extensions where the page DOM is controlled by the webpage, and Angular is running within a higher-privileged extension.

supersan2• 10 years ago

Angular is running within a higher-privileged extension.

Ok, thanks for the explanation. I've developed chrome extensions before but firefox very long time back, so my knowledge is rusty, but please tell me 2 things:

1. Say hypothetically if AngularJs can do it, doesn't that mean any Javascript can do it too? I mean Javasript contained within the extension code?

2. In chrome extensions we use "ng-csp", otherwise it won't run. Is this addressing the same thing in chrome and if so, why can't it do it in firefox?

laurent123456• 10 years ago

That doesn't make much sense. If there's a vulnerability in Angular, doesn't it mean that there's a vulnerability in the JS engine that runs the Firefox addons? And in that case, can't an attacker replicates whatever Angular is doing to make an exploit? Basically it sounds like it's something for Mozilla to fix, not the Angular team.

AgentME29• 10 years ago

Angular runs eval-like functions on HTML in the DOM. The DOM can be controlled by the webpage. When Angular runs in an extension (which has more permissions than the page) using the DOM controlled by the webpage, then the webpage can write code into the DOM that Angular executes from within the extension's security context. It's not the browser's fault that Angular trusts the webpage's DOM like that; Angular just isn't built for extensions.

jonny_eh• 10 years ago

But Angular only reads HTML that it's told to read, specified by the "ng-app" attribute/directive.

odbol_• 10 years ago

Exactly. If you can write a vulnerability in Angular, you can write it in vanilla Javascript as well. Unless Angular is using `eval()` or something and Firefox bans any use of `eval()`, which is reasonable...

bzbarsky11• 10 years ago

Unless Angular is using `eval()`

Which it is, as far as I can see, though it tried to make it slightly safer ... until version 1.6, when it gave up on pretending it's at all safe. The linked slide share from the github issue talks about this a bit. See http://www.slideshare.net/x00mario/an-abusive-relationship-w... slides 16-31 which talk about the sandbox angular tried to apply to the environment it did the eval() in, but in the end it's grabbing text from the DOM and doing an eval().

Note that in a browser extension doing text from the DOM (controlled by the web page) and doing an eval (with the privileges of the extension!) is obviously really really bad.

[Disclaimer: I work for Mozilla and I'm not an expert on Angular.]

AgentME29• 10 years ago

Firefox Addons Marketplace reviews and bans malicious and insecure extensions. There are legitimate uses of eval. Angular's use of eval (on DOM content) is insecure within the context of browser extensions.

mschuster91• 10 years ago

What is justifying this?

If the vulnerable part is in Angular, there's a 100% chance that someone can write code in plain JS that is vulnerable to the same attack. E.g. if there was something in the hashbang-url-router that would lead to eval'ing the code in the hash (which I just made up, but would describe such a class of vulnerability). This means it's pointless to ban Angular.

If something Angular does triggers an issue in the Firefox JS engine, it is Firefox that should be fixed, instead of allowing essentially a 0day exploit to be alive.

minitech2• 10 years ago

If the vulnerable part is in Angular, there's a 100% chance that someone can write code in plain JS that is vulnerable to the same attack.

“can”, not “will”. If everything that uses Angular is vulnerable (unlikely? I couldn’t say), why would you not ban it? This is along the lines of “If Heartbleed is in OpenSSL, there’s a 100% chance that someone can write code in plain C that is vulnerable to the same attack”. Yeah, they can, and it happens all the time, but why not fix a known hole?

E.g. if there was something in the hashbang-url-router that would lead to eval'ing the code in the hash (which I just made up, but would describe such a class of vulnerability). This means it's pointless to ban Angular.

This would be an excellent reason to ban Angular since a huge majority* of extensions never use eval().

* If this isn’t true… I don’t want to be in web dev anymore.

willvarfar2• 10 years ago

As AgentME clarifies above, Angular uses a lot of `eval()` of DOM elements, which is perfectly reasonable design decision when you control the contents (as you would if you used Angular in your own app), but a perfectly awful thing to do if the attacker controls the contents (as they would if you used Angular in a browser extension that processes 3rd party webpages).

jMyles2• 10 years ago

there's a 100% chance that someone can write code in plain JS that is vulnerable to the same attack

This is plainly false - please don't spread fear where it doesn't belong.

I'm sure you can think of some things that, when written into the privileged environment of an addon, create vulnerabilities that aren't possible in "plain JS."

There is nowhere near a "100% chance" that this is a problem for web apps that don't run as browser extensions.

andrewvijay• 10 years ago

Thats some solid hate right there. Not expected from Mozilla at all!

DannyBee3• 10 years ago

So, there's so many problems with this i don't know where to begin. Since folks have already noted the "not notifying google" issue, let me point out another:

Prior to banning, i can find literally no discussion or details about this being about to happen (IE no notice), pretty much ever.

You can see it was initially noted here: https://github.com/mozilla/addons-linter/commit/86f4dfb44355...

I can find no discussion around it (maybe it's there but i'm missing it? I looked in a lot of places).

You can see it fixed an issue to "warn third party developers of things we banned/don't advise", but there's nothing about initially banning anything there, and it was added with an initial ban list containing angular. I would have expected a page added, then a ban discussed, then a ban added. or something.

In fact, the details of the ban changed (https://github.com/mozilla/addons-linter/commit/2dcc2226e2ec...) repeatedly without notice either.

This seems really bad. I would have expected, at the very least, a heads up to extension developers or something or even a more public notice when it happened so that some discussion could be had about it.

Instead, it looks like the only way you would have found out about it is by trying to lint an extension and see it banned (IE after you developed it), or somehow random browsing of doc pages mozilla has.

TAForObvReasons• 10 years ago

Instead, it looks like the only way you would have found out about it is by trying to lint an extension and see it banned (IE after you developed it)

It's one of the big dangers of a "walled garden": you are subject to the whims of the arbiter.

ben_jones• 10 years ago

I wonder if any business-critical apps stopped working because of this?

tptacek3• 10 years ago

Google has repeatedly been equally abrupt in making breaking changes to other people's apps/products/pages/sites to resolve security problems. I'm glad they do, and I'm glad Mozilla isn't fucking around with stuff like this either.

DannyBee3• 10 years ago

I'll assume this is true (not my area!):

1. Just because one guy is an idiot does not mean the other should be.

2. You know, you may want to tell people and establish a process for telling people that this is happening (ie it should not take until person files github issue asking what's up when they validate their app to know what's going to be okay and not)

(and if the answer is "google doesn't do that", see #1 :P)

gima2• 10 years ago

Ugh, this kind of thing gets my blood boiling. It was clearly said that _a security researcher_ disallowed Mozilla from reporting the vulnerability forward. It's the individual to blame, not Mozilla.

In any case Personally I wouldn't want to run a large priviledged application as a browser extension when it's interacting with random webpages AND handling my security credentials. Too much attack surface.

nchelluri2• 10 years ago

Curious, do you use a password wallet/manager application, and if so how do you get passwords out of it and into the browser? I'd like to know if there's a better solution. (I use a browser extension.)

nathancahill5• 10 years ago

I think his point is that running the entire Angular 1.x framework to power a browser extension gives a large attack surface.

andrewstuart22• 10 years ago

GNU password manager for me, which interacts with the clipboard (or lets you do so on your own if you prefer).

The same is true of Keepass for windows, although IIRC you can also let Keepass actually alt-tab to the last window and do the typing for you.

ploxiln• 10 years ago

copy/paste. you can't trust password manager browser extensions.

Don't just take my word for it: https://twitter.com/taviso/status/769378052254015488

There were a few high profile ones recently reported by Tavis, but there have been many in the past, and it looks like no brand of password manager has consistently written safe browser extensions. They're written to be slick-looking and convenient, the actual security isn't visible enough to be a sales/popularity boost so it suffers. This very story/issue is another example in the making.

NeutronBoy2• 10 years ago

I use Keepass with auto-type. I know it's not perfect, but I feel better about auto-type than browser extensions.

AgentME29• 10 years ago

The issue with Angular in extensions has to do with the fact it uses eval on the page DOM, which is controlled by the webpage. The webpage can put code into the DOM, and then let Angular execute it from within the higher-privileged extension.

Angular <1.6 had a sandbox feature which blacklisted specific attacks like this, but was not a general solution and was specifically not intended as a security feature. They entirely removed the sandbox in 1.6 because people kept thinking it was a security feature: http://angularjs.blogspot.com/2016/09/angular-16-expression-...

I'm not going to fault someone for not reporting a specific vulnerability with a specifically not-security feature that has already been removed.

draw_down• 10 years ago

If they had let this through and people got owned because of it people would be screaming at Mozilla. Damned if they do...

TheRealPomax2• 10 years ago

Note that the Angular team is working with Mozilla and the researcher on this (see https://github.com/mozilla/addons-linter/issues/1000#issueco...) and that NDAs are a real, if insane, thing still to this day, and there is literally no way to legally compel any party to admit to being under NDA except in a court of law.

Should the researcher have told the Angular team? Yes. Should they have told the entire world? Probably no. Should Mozilla tell the world? Probably even less no. As long as the parties are talking (which they are), this is an unfinished security review on lock-down to prevent exploitation in the interrim.

andrewstuart22• 10 years ago

Also, let's not inundate the page with extraneous comments unless we're already part of one of the projects involved. We all have strong opinions, and the HN post has been linked in the issue, so the devs can come here to see discussion if they want it.

Let's be good GH citizens. :-) Nobody benefits from the Issue ending up locked because the discussion got too off-topic.

secmax3• 10 years ago

As long as the parties are talking (which they are), this is an unfinished security review on lock-down to prevent exploitation in the interrim.

I agree! There are a lot of Chrome extensions out there which could be affected. Immediate public disclose would be irresponsible.

codedokode8• 10 years ago

This "vulnerability" is harder to exploit in Chrome because extensions in Chrome (unlike in Firefox) have their own private DOM, and settings page have isolated DOM too. If an extension uses Angular only with its private DOM there is no vulnerability.

The vulnerability can be exploited only if an extension is running Angular on an untrusted page which is less likely in Chrome (but of course one should not underestimate the level of incompetency of a modern frontend developer).

UPD: @bzbarsky noted that Firefox is using the same security model as Chrome so both browser extensions can be vulnerable. To exploit a vulnerability, several conditions should be met: 1) extension should inject Angular into a web page 2) attacker should be able to find a way to get from content script context into extension's background page context.

masklinn3• 10 years ago

Chrome extensions are less of an issue though, no? IIRC Firefox addons are significantly more powerful than Chrome extensions, so locking things down tighter makes sense anyway, a low threat on Chrome could be much higher on FF.

michaelt2• 10 years ago

  NDAs are a real, if insane, thing still to this day

Some of the big security bugs recently have been disclosed to big players like Google and AWS before they were publicly disclosed.

If you want to retain that privilege, you need to show you can keep your mouth shut when security researchers disclose something to you - NDA or otherwise.

barkbro• 10 years ago

What's the rationale for disclosing vulnerabilities to for example Google before going public (unless the bug is in Google's software)?

AgentME29• 10 years ago

The mentioned vulnerability was most likely another sandbox escape. The sandbox is described as "not a defense mechanism" by the Angular team, and the sandbox was removed entirely in the 1.6 release[0]. They admit that Angular isn't secure for cases where an attacker can control the template: this case includes extensions! I'm not going to fault someone for not reporting a security issue with an already-removed feature specifically described as not a security feature.

Before anyone misreads this: the sandbox being removed in 1.6 doesn't mean that Angular 1.6 is safe to use in extensions. It just means that Angular stopped pretending it was safe there. A fundamental part of Angular is evaling text from the DOM. If the DOM is controlled by an attacker, such as a webpage trying to elevate to extension privileges, then you're out of luck. Sandboxing eval is a very large and difficult task that would bloat Angular, all for a use-case that they are not interested in. Angular 1.x is the wrong tool for the job.

[0] http://angularjs.blogspot.com/2016/09/angular-16-expression-...

esafwan• 10 years ago

That suddenly makes Angular look scary for some clients. vulnerability that is known to an entity/entities but unknown to the Angular developers or contributors....

codedokode8• 10 years ago

The vulnerability occurs only if you inject Angular into a web page from browser extension in some browsers. There is no vulnerability if you are writing a SPA using Angular.

Animats• 10 years ago

Using big external libraries in Firefox add-ons used to be totally prohibited. Jquery used to be prohibited outright. It's an undesirable practice. Add-ons operate at a higher privilege level than web pages. The low-quality webcrap that can be tolerated on a web page has no place in a privileged add-on.

omouse• 10 years ago

Agreed and this is why React has been given a pass I think, because it's only for display purposes.

vmasto• 10 years ago

Really it doesn't matter if it's for display purposes or not. It all boils down to implementation. I can make a view library riddled with XSS vulns in very little time.

spicyj• 10 years ago

React is actively maintained and doesn't have any known security vulnerabilities.

hannob• 10 years ago

I'm not sure if this is the same case, but I assume it is: if you're wondering why the researcher doesn't want to share the vuln listen to this talk: https://www.youtube.com/watch?v=U4e0Remq1WQ

Roughly at 41:30 he explains why he doesn't want to disclose the vuln. The tl;dr is he thinks the sandbox is broken beyond repair and whatever fix they come up he can create another bypass for the sandbox. But he doesn't want to do this all the time and he needs his vuln as a poc to show to customers if they abuse the sandbox.

icecube• 10 years ago

That was a good talk. I highly recommend watching the entire video.

cfvergara• 10 years ago

Why not use Google Caja instead of a separate sandbox?

minitech2• 10 years ago

Overkill for what was never intended to be a sandbox for untrusted code. The “sandboxing”, like Django templates’, Jinja, Nunjucks, etc. is a well-intended measure to keep logic out of templates, but in practice only really gets in the way and causes mistaken assumptions about security.

angry-hacker2• 10 years ago

Can someone explain me:

If angular can do it, so can just plain javascript? Then it's a problem with their extension architecture?

As much as I hate bundling big libraries everywhere, why ban angular?

Also, is it possible the researcher wants to get money from Google and didn't want the vulnerability to be shared?

positr0n• 10 years ago

I have no information one way or the other, but maybe the issue isn't that angular can do it, but that angular does do it. So any extension using angular is vulnerable by default.

AgentME29• 10 years ago

Yes, you can write vulnerable code in plain javascript:

    eval(document.querySelector('.foo').textContent);

In a regular web page where you don't allow the user to insert arbitrary HTML, it's a perfectly fine line allowing you to store code in the DOM.

If you do that in a browser extension where the DOM is controlled by the web page, then you've got a big security vulnerability: the webpage can put anything it wants into a foo tag and then your extension will execute it with its privileges! Your extension will be taken down from the Firefox Addons Marketplace if it's reviewed and this line is found running. If lots of extensions added this line, then Mozilla would probably automate blocking extensions from containing it.

Angular 1.x does something like this line. It's perfectly fine in web pages where you control the DOM, but is insecure if the DOM comes from an untrusted outsider!

angry-hacker2• 10 years ago

Why doesn't Firefox simply disallow eval? You would get an error in console explaining and that's it.

ctide• 10 years ago

I had an extension a while ago that I was attempting to publish to the Firefox app store and it was rejected on grounds of using eval. I don't remember why I needed to use eval, but basically this is something they do already. I'm guessing that previously they were allowing for an Angular exception.

buremba• 10 years ago

This thing makes me believe that we should not use any OSS project which released by a big companies such as Google and Microsoft. Even if they don't say that they're dropping support, when they start to work on another project, it won't be a community-driven project and slowly die.

jmcdiesel2• 10 years ago

Isn't any "vulnerability" in a JS framework a vulnerability in the browser's own handling of securing it? Like, there is nothing angular is doing that someone else couldn't do, intentionally, to create said issue, right? Wouldn't the correct handling of this to be to secure the damned interpreter thats running the code to prevent it from having the effect they are trying to mitigate?

This feels like a lazy shifting of blame

AgentME29• 10 years ago

Angular evals text stored in the DOM. If you alone are in control of the DOM (like in a normal webpage), there's no issue. If someone else is in control of the DOM (you're running Angular in a higher-privileged extension running on a random webpage's DOM), then they can put code into the DOM which then gets picked up by Angular and executed within the extension with the extension's full permissions. This isn't an issue inherent to the language or browser at all. This is an issue just comes from that Angular 1.x is designed for use-cases where the DOM is trusted, and that's not the case for browser extensions.

jmcdiesel2• 10 years ago

But thats not special to angular... right? You can write that in vanilla javascript just the same - the issue is that the script running in the extension is given the ability to do that. They dont seem to be blocking a feature in javascript, they seem to be blocking a lib that uses it. Angular can't do ANYTHING that any other bit of javascript can't do in the same context.

Angular is just JS, its not special JS, its just JS. If angular can do something, it can be done without angular so blocking angular does nothing to prevent the vulnerability.

adrin2• 10 years ago

Uhm, wait what? Firefox extensions can execute literal code from visited a website? To me that sounds like the root cause of the problem and a glaring security hole - either the website has to be sanitized/projected into a harmless dom abstraction or extensions shouldn't be able to use any kind of dynamic evals.

Sure angular may be vulnerable by default but good luck thinking that all other extensions out there are safe and not using evals at any point.

AgentME29• 10 years ago

either the website has to be sanitized/projected into a harmless dom abstraction

Should Firefox contain code to recognize text that looks like Angular templates and then break it somehow? That'd be extremely specific.

Eval isn't an inherently unsafe feature, and it doesn't have a monopoly on insecurity: Angular doesn't even require eval. It can run without eval in a CSP-supporting mode that's equally vulnerable.

pfooti• 10 years ago

Let me make sure I understand this. This vulnerability is basically because the addon authors are using angular to parse webpages, and therefore because they don't have control over the DOM elements angular is being used on, they're vulnerable to all the xss escapes in [0], right?

Because as far as I can tell, all of the escapes in [0] require the attacker to write to the DOM being evaluated by the angular engine. Normally this isn't a big deal, because the developer controls the DOM. In more pedestrian situations, if you've got a wiki, cms, forum, or other situation where untrusted people are creating content, you can't give those content creators the ability to write to parts of the DOM where an xss abuse might happen, and if you do it is pretty much your fault anyway (angular isn't really to blame here, because if you're letting users write to the DOM directly you've got trust issues).

The mozilla situation is particularly problematic because the mozilla addon runs its javascript context in some elvated privilege mode, and normally that javascript just manipulates the DOM directly to generate addon-specific UI (like password fill helpers, for example). But because that angular is being run on a DOM outside of the control of the addon authors, it's also subject to all kinds of XSS escapes.

I get that, it's fair. Seems like, though, this isn't really an angularjs issue specifically. It feels like this is a broad problem with the security model for browser addons. Like: replace angular with some other view library that you rolled yourself and it could still have all kinds of issues.

Basically anything that uses the DOM to store state (instead of a one-way state -> dom transformation) is subject to manipulation by malicious DOM injections, be they from forum posters or creators of pages that will be visited by plugin users. So, again: I see why angular1 has issues here. But this is a much bigger security hole, honestly. I don't think the javascript runtime for plugins should expose anything to the js running on the page, but that's a lot more complicated, since the plugin runtime is almost always really interested in spidering the page DOM and altering it by responding to the state of that DOM.

0:http://www.slideshare.net/x00mario/an-abusive-relationship-w...

AgentME29• 10 years ago

I don't think the javascript runtime for plugins should expose anything to the js running on the page, but that's a lot more complicated, since the plugin runtime is almost always really interested in spidering the page DOM and altering it by responding to the state of that DOM.

Firefox/Chrome/Safari extensions already run in an "isolated world" so that they have separate sets of global variables and DOM-wrappers, so that javascript values never leak directly and modifications to globals don't affect other worlds. However, they all see and manipulate the same content in the DOM. I'm unsure if you're proposing anything different from the current situation.

dancek3• 10 years ago

Many commenters here seem to be completely misunderstanding the situation.

Browser extensions are really dangerous; if you need to keep your machine secure, you shouldn't use any IMHO. By definition, browser extensions need to be able to access things such as page content. What would stop someone from writing a extension that captures your bank credentials? Nothing.

Obviously no security-conscious user is going to install a bank credential stealing extension. But what about bugs in extensions? If a buggy extension can be made to execute arbitrary code, it is as dangerous as a malicious extension (if the arbitrary code execution works in the same circumstances).

Angular 1.x basically runs eval on DOM content. That's how it works, it's not a vulnerability in normal use. You make a web page using Angular, and possibly the user has a way to eval arbitrary JS code through Angular, but then they have the developer console so they can run arbitrary code anyway.

With browser extensions it's different. The extension is from one source and runs with one set of privileges, and the page comes from someone else and has less privileges. Now if anything from the page can be eval'd in the extension, that's privilege escalation. Someone creating a site can run malicious content as a browser extension.

It's probably possible to sanitize all external inputs used in the browser extension such that privilege escalation isn't possible, but the Angular team has tried hard with their sandbox solution with no success. Extension developers will hardly do much better, so it makes sense for Mozilla to ban the whole library.

Angular wasn't designed for browser extensions.

WRT the security researcher and Mozilla not disclosing other known sandbox vulnerabilities, that's missing the point (but an interesting discussion in itself).

jguegant• 10 years ago

BROWSERS are really dangerous; if you need to keep your machine secure, you shouldn't use any IMHO. By definition, browsers need to be able to access things such as page content. What would stop someone from writing a browser that captures your bank credentials? Nothing. Obviously no security-conscious user is going to install a bank credential stealing browser. But what about bugs in browsers? If a buggy browser can be made to execute arbitrary code, it is as dangerous as a malicious browser...

At the end, it's a matter of trust in your browser or your extensions.

kentosi• 10 years ago

I see where you're getting at, but with only a handful of browsers* maintained by large organisations eager to protect their reputations vs a plathora of extensions out there, your argument doesn't hold so well.

* I'm assuming usage of Chrome/IE/Firefox/Safari here.

dancek3• 10 years ago

Obviously.

The quoted paragraph is buildup to the fact that AngularJS evals content on purpose, and does not really even try to be secure against maliciously-crafted DOM. Browsers, on the other hand, are designed to resist attacks.

But yes, certainly you need to trust the browser more than an extension.

the84723• 10 years ago

It's probably possible to sanitize all external inputs used in the browser extension such that privilege escalation isn't possible, but the Angular team has tried hard with their sandbox solution with no success. Extension developers will hardly do much better, so it makes sense for Mozilla to ban the whole library.

Sandboxing in JS should be possible these days. Spin up an iframe, add the sandboxing attribute, load javascript into it, postMessage the code you want to execute to it, await the return value. voila, you executed untrusted code in an isolated origin context.

AgentME29• 10 years ago

You can't run code that depends on variables in the page context though. If all the input values are serializable, then you can postMessage them into the iframe too, but you can't serialize objects with arbitrary methods, etc. The code you run in the sandbox can't return back a rich object with arbitrary methods because that has to get serialized back out. You can't use getters and setters to transparently proxy all accesses because postMessage is asynchronous. Even if you restrict everything to only dealing with objects with promise-returning functions, I'm not entirely sure if you can get this all to play nicely with garbage collection (say you have an object outside of the iframe which is only referenced -- through the proxy system -- by an object inside the iframe which is only referenced by that object outside of the iframe)...

Iframe-sandboxing is far from a drop-in solution to this type of problem into an existing codebase.

revelation• 10 years ago

Why is Angular from the extension run on DOM from the page?

You make it sound automatic, but surely this must be manually triggered by the extension in question?

AgentME29• 10 years ago

If an extension wants to modify the DOM of a page, then it runs with the DOM of the page.

rtpg• 10 years ago

But the issue of preventing arbitrary Javascript code from running based on user input isn't limited to Angular, it's a problem since the beginning of time!

What about Angular is so special that it needs to be blacklisted? It will likely still be safer than ad-hoc client-side templating that people will do instead.

Nitramp3• 10 years ago

Hey. I work on security for Angular.

It's probably possible to sanitize all external inputs used in the browser extension such that privilege escalation isn't possible, but the Angular team has tried hard with their sandbox solution with no success. Extension developers will hardly do much better, so it makes sense for Mozilla to ban the whole library.

AngularJS runs expressions that are in your page's HTML when it initializes (or when you explicitly call angular.bootstrap on an element), but only on the page where it is loaded. If an extension uses Angular within the extension, that's perfectly fine, security wise. Unless the developer explicitly requests it, pages visited cannot move code into an extension's context (which would be dangerous in any case, Angular or not).

Even when the developer explicitly moves data from a web page into the extension context, this does not cause a security issue, even when the data ends up in the DOM. Once loaded, Angular does not revisit the DOM to run expressions in it (otherwise all Angular pages would be compromised). Care has to be taken when using things like ng-bind-html, but the security profile for an extension is the same as a regular web page here. With Angular's $sce service and automatic escaping/sanitizing, it's actually reasonably easy to write safe web applications that properly escape user input.

All of this is unrelated to the expression sandbox. The sandbox was never intended to be a security feature, but rather a feature to keep developers from shooting into their own foot (e.g. by creating global variables). It was considered to be defense-in-depth mechanism for a while, but it turns out it is at best misleading for users who believe it protects them. That is why we removed it.

dancek3• 10 years ago

Thanks for the reply. I mistook the sandbox to be related to $sce. It's been a while since I last coded Angular.

So you're saying that Mozilla is mistaken in their decision, and the only way for page content to be eval'd with extension privileges is if the developer was careless with ng-bind-html or $compile?

seanwilson• 10 years ago

The sandbox was never intended to be a security feature, but rather a feature to keep developers from shooting into their own foot (e.g. by creating global variables). It was considered to be defense-in-depth mechanism for a while, but it turns out it is at best misleading for users who believe it protects them. That is why we removed it.

For apps using Angular 1.5, do any changes need to be made to move up to Angular 1.6 without the sandbox? Does Angular lose any features with the removal of the sandbox?

byuu• 10 years ago

By definition, browser extensions need to be able to access things such as page content. What would stop someone from writing a extension that captures your bank credentials? Nothing.

Completely agreed. This is why it's so frustrating that all of the browser vendors have moved to this, "gut every minor option/feature possible, people can just get an extension" attitude.

For Firefox:

* removing the option to not maintain download history

* removing the option for the compact drop-down menu from the URL bar

* forcing tabs on top

* forcing refresh button to the right-hand side of the interface

For Chrome:

* removing backspace navigation (you may dislike it, but others don't)

* disabling middle-click to scroll on Linux

* removing the option to set your new tab page (eg to about:blank)

* not letting you prevent HTML5 video autoplay

* not letting you disable WebRTC

Just the backspace extension alone requires basically carte blanche access to everything just to be able to insert a tiny Javascript function to catch the keypress.

I'm not asking for us to go back to the Mozilla suite with integrated mail client, news reader, etc. Just ... it's okay to have an "advanced options" section that lets us control some of this really simple, really basic stuff. And not only okay, a major security benefit to do so. All the focus on web security, you'd think they'd take this stuff more seriously.

iotscale• 10 years ago

Or more fine grained permissions.

They could at least make it possible choosing not to upgrade a very simple extension which we may have been personally reviewed.

I want a fixed (read: no updates) extension that does this: On key press, check if the key is backspace, when it is, check if any form element is focused, when not, go back. One line of JS, I guess three with nice formatting. If I create this, I need to submit it to the Chrome Store so Chrome won't complain about untrusted extensions.

Of course they also removed the ability to tell it that I know what I'm doing.

fuzzy2• 10 years ago

By definition, browser extensions need to be able to access things such as page content.

On Firefox/XUL maybe. Web Extensions (like in Chrome) work much like Android apps: You need to acknowledge their desired permissions up front. They can’t request more later.

Of course you may need these permissions to create your extension.

y0ghur7_xxx• 10 years ago

The vulnerability described by op applies to chrome just the same. Once the addon has `pageCapture` permission, an angular 1 exploit would work just the same.

emn132• 10 years ago

Many extensions have full access to all webpages, also in chrome; there's no sandbox or anything similar safely separating extension from page. That's not a bug or missing feature: it's by design! Many extensions fiddle with all kinds of page aspects as part of their core functionality.

An adblocker that can't inspect the page dom would likely not work very well.

xxkylexx4• 10 years ago

Angular and Firefox teams are working to resolve the issue. The issue is not related to sandbox ... see https://github.com/mozilla/addons-linter/issues/1000#issueco...

Angular 1.x Banned from Firefox Addons

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