MESSAGE
DATE | 2017-02-15 |
FROM | Rick Moen
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SUBJECT | Subject: [Learn] [conspire] [svlug] AnC side-channel attack: In which ASLR
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From learn-bounces-at-nylxs.com Wed Feb 15 18:10:17 2017 Return-Path: X-Original-To: archive-at-mrbrklyn.com Delivered-To: archive-at-mrbrklyn.com Received: from www.mrbrklyn.com (www.mrbrklyn.com [96.57.23.82]) by mrbrklyn.com (Postfix) with ESMTP id 33B6B161337; Wed, 15 Feb 2017 18:10:17 -0500 (EST) X-Original-To: learn-at-www.mrbrklyn.com Delivered-To: learn-at-www.mrbrklyn.com Received: by mrbrklyn.com (Postfix, from userid 1000) id F01AE161336; Wed, 15 Feb 2017 18:10:14 -0500 (EST) Resent-From: Ruben Safir Resent-Date: Wed, 15 Feb 2017 18:10:14 -0500 Resent-Message-ID: <20170215231014.GA26192-at-www.mrbrklyn.com> Resent-To: learn-at-mrbrklyn.com X-Original-To: ruben-at-mrbrklyn.com Delivered-To: ruben-at-mrbrklyn.com Received: from linuxmafia.com (linuxmafia.COM [198.144.195.186]) by mrbrklyn.com (Postfix) with ESMTP id 47B76161336 for ; Wed, 15 Feb 2017 17:18:55 -0500 (EST) Received: from localhost ([127.0.0.1] helo=linuxmafia.com) by linuxmafia.com with esmtp (Exim 4.72) (envelope-from ) id 1ce7ta-0006eT-O4; Wed, 15 Feb 2017 14:17:54 -0800 Received: from rick by linuxmafia.com with local (Exim 4.72) (envelope-from ) id 1ce7tZ-0006eO-9t for conspire-at-linuxmafia.com; Wed, 15 Feb 2017 14:17:53 -0800 Date: Wed, 15 Feb 2017 14:17:53 -0800 From: Rick Moen To: conspire-at-linuxmafia.com Message-ID: <20170215221753.GK6937-at-linuxmafia.com> MIME-Version: 1.0 Content-Disposition: inline Organization: If you lived here, you'd be $HOME already. User-Agent: Mutt/1.5.20 (2009-06-14) X-BeenThere: conspire-at-linuxmafia.com X-Mailman-Version: 2.1.13 Precedence: list X-SA-Exim-Connect-IP: 127.0.0.1 X-SA-Exim-Mail-From: conspire-bounces-at-linuxmafia.com X-SA-Exim-Scanned: No (on linuxmafia.com); SAEximRunCond expanded to false X-UID: 35053 Subject: [Learn] [conspire] [svlug] AnC side-channel attack: In which ASLR doesn't protect you from dumbness X-BeenThere: learn-at-nylxs.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: learn-bounces-at-nylxs.com Sender: "Learn"
Further worthwhile links: https://www.vusec.net/projects/anc/ https://news.ycombinator.com/item?id=13650611
----- Forwarded message from Rick Moen -----
Date: Wed, 15 Feb 2017 13:33:45 -0800 From: Rick Moen To: skeptic-at-linuxmafia.com Subject: Re: [skeptic] It isn't Windows vs Apple anymore - all modern CPUs can be compromised Organization: If you lived here, you'd be $HOME already.
Quoting Beth W (badastrum-at-gmail.com):
> New ASLR-busting JavaScript is about to make drive-by exploits much nastier > A property found in virtually all modern CPUs neuters decade-old > security protection. [...] > Full article at > https://arstechnica.com/security/2017/02/new-aslr-busting-javascript-is-about-to-make-drive-by-exploits-much-nastier/
I also recommend the actual research article discussed, http://www.cs.vu.nl/~herbertb/download/papers/anc_ndss17.pdf
I'm not the least bit surprised, because Javascript has always been a disaster (but also see below; it's not _really_ Javascript but rather what it's called upon to do). It's always been absurdly overfeatured, and so everyone with elementary common sense has been severely curtailing what it's permitted to do, either using a _well-tuned_ NoScript (i.e., not just load the extension and drool) or its latter-day competitor uBlock Origin or uMatrix (same qualification).
Users almost never are willing to do that, because users overwhelmingly behave like morons, never even looking to tweak the defaults of their software let alone questioning the necessity and wisdom of excessive functionality, and correcting that. At the end of my lecture 'The Wild, Wild Web: Web Browser Security, Performance, and Privacy' in Feb. 2011, I asked for an honest show of hands about how many in the audience were seriously considering following my recommendations, I think there were three hands. I thanked everyone for their honesty. And that was a _technical_ audience, but they were nonetheless lazy and borderline inert. This is the reality.
I'll mention in passing that Javascript is overfeatured but that that any other language pressed into its role would pose the same problem, and that is that a remote Web server asks your browser 'Will you be willing to run unknown program code I'm about to hand you that will run in a full-blown Turing-complete environment and do basically damned near anything it wants, with your user to be told the results later?', and your browser says 'Sure, I'll start that for you.'
And why is this the case? Why does even Firefox ship without the means to curtail and control this stuff, with that task being consigned to extensions and aftermarket configuration? Because advertising, and because user-tracking[1]. Because Sutton's Law.
As one of the reader comments on ArsTechnica says, ASLR is and always was security through obscurity. The real problem is accustoming users to blandly running complex, unknown, third-party code that they have absolutely no reason to trust and want to run -- just because someone makes a buck from that. If your security depended on ASLR, you already lost.
To translate to man-in-the-street, ASLR is this: 'Problem: People run exploit code. That code, once running, finds running code and its data structures in the user's computer memory and messes with it, in order to do harm. Solution: Let's shuffle-around the vitual memory addresses of running code and its data structures to make them unpredictably located.' The research paper documents a pretty easy side-channel method for exploit code to _find_ that running code and data structures.
Darn, what a pity users keep running highly untrustworthy, complex, unknown code from nobody-in-particular! If only they had... what's that phrase?... a sense of self-preservation.
But of course computer users have none. It's been shown repeatedly that most will give away their corporate-network passwords for candy, for example.
You want a comprehensive layered response that still keeps Javascript in the picture, look no farther than Qubes OS, which sandboxes everything in individual hypervisor VMs. Me, I'll continue to just corral and whittle down Javascript through other means. As I said during my lecture, Javascript is really the keystone security problem.
And if Javascript hadn't been the advertising/tracking-driven keystone security problem, something equally ugly would have taken its rotten niche.
[1] This industry goes under a wealth of euphemisms, including metrics, 'Web bugs', behavioural marketing, a lot more.
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