The DMZ

4:01 AM

According to my mom, my first word was (looking up at the sky) 'Wow!'

6:42 AM

@Thomas - excellent! Have made a couple of minor additions (added a couple of links, and a QoTW footer) and scheduled for publication at 1200UTC

Interesting one - had a remark on security.stackexchange.com/questions/21115/… that it was a quiz question, and AT&T would take action if we published answers...

they posted the comment as a suggested edit, so I had to reject ... and I only need 1 more to get my badge...oh, the moral dilemma :-)

Rory Alsop

7:39 AM

Heh- no dilemma, the badge is for reviewing so a normal reject still worked.

Lucas Kauffman

11:13 AM

Why is it that every time I read 'for whom' automatically I start playing for whom the bell tolls in my head

2

Thomas Pornin

@RoryAlsop GOOD.

Rory Alsop

12:02 PM

@LucasKauffman because metal rules! \m/ \m/

Stack Exchange

12:20 PM

Stack Exchange Security Blog: QoTW #37: How does SSL work ?

Thomas Pornin on October 05, 2012

In this week’s question, we will talk about SSL. This question was asked by @Polynomial, who noticed that our site did not have yet a generic question on how SSL works. There were already some questions on the concept of SSL, but nothing really detailed.

Three answers were given, one by @Luc, and two by myself (because I got really verbose and there is a size limit on answers). The three answers concentrated on distinct aspects of SSL; together, they can explain why SSL works: SSL appears to be decently secure and we can see how this is achieved. …

Rory McCune

12:39 PM

Evening @TerryChia

Terry Chia

@RoryMcCune hey there.

reading the SSL blog post now.

Thomas Pornin

Is there a new badge thing which would explain the apparent rush for mass-editing and retagging ?

Terry Chia

@ThomasPornin There are the new review badges,

Scott Pack

1:01 PM

@ThomasPornin Rory is also trying to clean up tags

I've been going through, every so often, to clean up spelling and such, but I haven't done that in a while.

Thomas Pornin

@ScottPack I hope he doesn't end up merging all tags into a single über-tag rory

4

Scott Pack

@ThomasPornin That would be a meta-tag

Rory McCune

@ThomasPornin you say that idea like it's a bad thing :op

2

Thomas Pornin

@RoryMcCune Well, it would mechanically grant me the golden rory badge.

2

Scott Pack

So, @Thomas. I have a plan.

Do you know what happens to badges when you no longer qualify for them?

Thomas Pornin

1:12 PM

@ScottPack I think most badges are never revoked.

Scott Pack

@ThomasPornin Correct.

Thomas Pornin

You plan to do mass-scripted retagging to get a thousand gold badges ?

Scott Pack

If you earn a badge, and no longer qualify for it, you keep the badge. You do not, however, re-earn it if you requalify.

I just looked at the math. I wouldn't actually qualify for any gold badges, since I only have 70 answers.

Hell, I'm 10 away from qualifying for a silver badge

@ThomasPornin So, no. I don't have any devious plans right now.

Terry Chia

@ThomasPornin I think SEI would consider it an abuse of the system and revoke them. :P

Thomas Pornin

@ScottPack You could first retag everything to aaaa, then do it again with aaab, and so on.

Scott Pack

1:16 PM

@ThomasPornin Mathematically I can't qualify for any tag badges except bronze. So, won't really help, no.

Thomas Pornin

Such badges are granted with a nightly cron job (I just tested it again last night) so this is limited in rate

I have 544 answers and I can put 5 tags per question. I could get 10 gold badges per day.

Scott Pack

Yeah, the threshold is 200 answers and 1k upvotes. So, for ease of conversation, let's round that out to be a minimum of 200 answers and 10k rep.

Thomas Pornin

@TerryChia It would only be fitting that this kind of abuse would be first tested on security.SE.

Scott Pack

Accounting for accepts and bounties and questions then you're probably looking a more realistic minimum of 13-15k.

Thomas Pornin

@ScottPack There is also the upvote rate. So that's a minimum of 200 answers or 1k upvotes, whichever is most limiting.

Scott Pack

1:23 PM

@ThomasPornin You have to hit both minimums. For example

> Earned 1000 upvotes for at least 200 answers in the encryption tag

Thomas Pornin

@ScottPack Yes. So it basically excludes @Polynomial and @Hendrik.

Only six people could do it.

Scott Pack

Completely unrelated: Microsoft bought PhoneFactor.

@ThomasPornin Correct.

M'vy

Hiya. PhoneFactor?

Scott Pack

@M'vy It's a phone based two-factor solution. Works with LDAP, Radius, IIS, Windows TS, and LogMeIn.

M'vy

1:39 PM

interesting.

Rory McCune

it'll be a very good thing for MS services like Office365 I reckon, as the lack of two-factor auth is a bit of a glaring omission at the moment

Scott Pack

I've tested it out, pretty not bad product. You get almost all the features for free for up to 25 users.

Oh, and they also offer an api and several sdks for your custom apps.

jrg

adds PhoneFactor to his list of two-factor options

Iszi

It's really funny how I have some badges on sites where I almost never do anything, that I haven't gotten here. For example, I just got a "Famous Question" on Unix and Linux.

jrg

and the list grows.

Terry Chia

1:53 PM

@jrg hi sheldon

jrg

@TerryChia facepalm Hi.

Terry Chia

I only noticed it when @Iszi mentioned it awhile back.

Lucas Kauffman

CodesInChaos

Why is asking questions so much harder than answering questions -_-

Iszi

@jrg Here you go...

Terry Chia

2:02 PM

@Iszi HAHAHA! good one!

Thomas Pornin

@CodesInChaos Because when you write the question, you cannot help thinking about the awesome answer you could give to it, and, in fine, you cancel the question because you have answered it already in your head.

Lucas Kauffman

2:28 PM

wtf xD

Ernst & Young is hiring: Oracle DBA in Thiruvananthapuram Area, India

Rory McCune

2:48 PM

on the theme of WTF , the SHA-3 song anyone... youtube.com/watch?v=evSimlbu-IA&feature=relmfu

Lucas Kauffman

3:36 PM

IT people

we are weird by nature

Terry Chia

4:05 PM

plus.google.com/103369295503420571401/posts/FHftExdjPrJ

This is hilarious.

Thomas Pornin

4:27 PM

Ah ! It happened again. I was writing a question for SO, and then the answer struck me. That's one more question which will never go live.

CodesInChaos

4:43 PM

For about half the questions I ask on crypto.SE I could find the answer with a bit of effort, but still post them since they might be interesting for others too.

and crypto suffers from a lack of questions, so asking a bit more helps the site

Thomas Pornin

4:55 PM

In my case it was a question very specific to my situation, involving analyzing access rights programmatically in an Active Directory server. I just found out an elegant way to totally bypass the issue, making the question irrelevant (to me -- and it is too specific to be relevant to anybody else anyway).

At my work, a local DNS server has been down since this morning (so at least 5 hours since the incident was reported). It is amazing how many systems just stop working when the DNS is down. I wonder what the people who should repair it are doing right now.

Jeff Ferland

5:14 PM

@ThomasPornin Probably posting on Serverfault. Something like, "The Internet stopped working for the whole company. Somebody please help me figure out why. It's very urgent."

3

Ladadadada

5:25 PM

@ThomasPornin I vaguely remember back when I was using Solaris that they wouldn't even boot without a DNS server available.

Thomas Pornin

@Ladadadada How did they boot the DNS ?

Ladadadada

Er... I never asked that question. It was up and running and I didn't mess with it.

Thomas Pornin

(Although I used to have Solaris at home, on a PC without any network at all, in particular no DNS, and it booted just fine. Wrote half of my PhD thesis on it.)

Ladadadada

Ah, that's right. It was Jumpstart. You could boot a box normally without DNS but you couldn't Jumpstart a box without it. And since we needed to have a separate VLAN for the jumpstart thing (for the DHCP) we needed to set up a separate DNS server on that VLAN as well.

CodesInChaos

6:14 PM

Weird that we haven't seen any SHA-1 collisions yet

2^60 sounds pretty cheap

Thomas Pornin

That's not cheap for me. You must be quite rich.

A 2 GHz quad-core PC can compute, in ideal conditions, about 2^34 elementary operations per second.

2^26 seconds is a bit less than two years.

but it takes more than one elementary operation for SHA-1, rather a thousand

So we are talking about something like 2000 PC-year

That's one year with 2000 PC, or 2000 years with one PC

Either way, not totally cheap for an amateur.

And beyond budget for most academics, too.

Apparently there is an ongoing effort for computing a discrete logarithm instance on a 128-bit elliptic curve; that's a 2^64 effort. It involves a lot of universities, and they hope to be done in about ten years. Maybe they could stop that, and instead switch to a SHA-1 collision -- but I doubt they'd find enough budget to do both.

Lucas Kauffman

7:19 PM

@ThomasPornin whatabout 5 GTX 590?

that would set you back 2.5k

CodesInChaos

I estimate the cost at 10k$

Lucas Kauffman

thats 1024* 5

each core at 774 mhz

CodesInChaos

Not something I'd like to pay out of the pocket, but not that expensive

Lucas Kauffman

anyway I dont know who it was that was working on a project for a client where you could easily add a special board with 4 580 GTX to a cluster

one unit was about 3k I think

CodesInChaos

GPUs are pretty fast at hashing. A single CPU can do around 3GHash/s with SHA-1

Lucas Kauffman

7:22 PM

buy a 100 of those and it4s GG

Thomas Pornin

@LucasKauffman There may be details. The last SHA-1 cracking effort I heard of was a research for good differential paths, organized by Reichsberger at Graz University. He was looking for volunteers, and he told me that this was a kind of backtrack which did not map well (not at all) to GPU.

For these attacks, this is not just a matter of computing a lot of hashes.

CodesInChaos

That's the interesting question. 2^60 SHA-1 invocations isn't that expensive. But if some other costs, such as RAM are involved, it might be much more epxensive

Lucas Kauffman

ok but for research lets say a 100k budget is really small

Thomas Pornin

@LucasKauffman If the old-fashion generic CPU is the optimal platform for the attack (and it may well be), we are talking about running 8000 cores for one year.

Buying 8000 2 GHz cores for 100k$ looks a bit optimistic to me. But maybe loaning... (i.e. running in Amazon's cloud)

Lucas Kauffman

okay

300 k then

also dont forget they often get very reduced prices

I know my university had 75% discount

with dell

Lucas Kauffman

8:44 PM

anywayy whats cooking here?

Polynomial

9:10 PM

Well, I'm in the middle of a dilemma.

without giving too much away, there's a potential for me to switch careers to something highly security related, for a large company that deals with a lot of highly sensitive information (police, government, defence, etc.)

but, as is customary for that kind of work, they require a high level clearance check, which is a very invasive process

and I happen to be rather passionate about my personal privacy... so :/

so the potential choice (if the employment opportunity goes forward) is between money and employment prospects, or maintaining my personal privacy

Thomas Pornin

9:25 PM

@Polynomial You could see the choice like this: do you prefer that they run an invasive process with your knowledge and approval, or that they do it anyway in case you were a cyber-terrorist ?

Polynomial

@ThomasPornin That's one way to say it, but thankfully the UK has a surprisingly good track record on respecting privacy.

I'm certainly not dismissing the opportunity, and I'm not saying I have anything to hide - it's just the principle of the matter.

Thomas Pornin

@Polynomial Some would say that this means the UK is very good at keeping secrets, e.g. not being caught invading the privacy of citizens.

Correspondingly, you can "trust" them: whatever they find, they will not tell anyone.

Polynomial

@ThomasPornin Haha, you could indeed put it like that ;)

Either way, I'm not discounting it or permitting it until I know what the reward is.

Polynomial

9:44 PM

Hmm, it seems DV isn't as gruelling as I first thought.

Rory McCune

@polynomial from what ive heard ( all anecdotal) DV checks are pretty thorough but the main focus is whether you have anything in your past which could be used by someone to blackmail you..

SC by contrast is less than ive had from HR when being hired in some companies...

Polynomial

Yeah, was just chatting to someone who's been through it.

Lucas Kauffman

@Polynomial well tbh my father was an officer in information operations for NATO, you don't actually have privacy...

or thats what I learnt of it

Rory McCune

@polynomial ahh well their info will trump mine then :)

Lucas Kauffman

@Polynomial just do it already so you can get a sponsored ticket for Brucon 2013 :D

Polynomial

9:49 PM

lol

sadly, no. it takes A WHOLE FRICKIN YEAR

(well, 6-12 months)

which is pretty insane, if you think about it

Rory McCune

Yeah its a catch22 for consultants, you need it for a job, cant get sponsored to do it unless you have a job that requires it, and noone will wait that long for you for a job..

Polynomial

well in this case they're looking into possibilities.

Rory McCune

That said once you have it its a good bonus on salaries due to the dearth of people with it :)

Polynomial

e.g. get lower clearance and work in a different department for that time.

or stay where I am and the job offer will always be there once it goes through

which would be odd

Rory McCune

Yeah SC is relatively quick IIRC

Polynomial

9:53 PM

SC is less than a month usually

that literally is a glorified CRB check

essentially "does he/she pass a CRB check, and are they on any watchlists?"

CodesInChaos

so many abbreviations

Polynomial

basically gives you clearance for the sort of information that you wouldn't care too much about some Anon skiddies getting hold of, but you certainly wouldn't want Abu Hamza and his buddies knowing :P

Lucas Kauffman

10:18 PM

reminds me to send an email for my PES clearance on monday

that's been pending for way too long atm

Polynomial

Penis Enlargement Surgery requires clearance these days?

;)

Scott Pack

11:23 PM

Building codes

@Polynomial You'uns

Transcript for