The DMZ

Terry Chia

01:30

@LucasKauffman what's wrong with shooting fishes? :P

Stack Exchange

05:31

The prosecution calls Gottfried Leibniz.

Terry Chia

08:43

I'm finding it tough to decide between Beth's and Thomas' answer to my which level of crypto question.

Both are excellent, so I guess i'll accept one and reward the bounty on the other.

AviD

09:55

Brilliant people can't sufficiently predict stupidity.

CodesInChaos

And they typically have their own areas of stupidity

CodesInChaos

10:10

Which SE site does this question fit? security? webmasters?

0

Q: How can I verify my website?

How can I make my website display a green label in the address bar of the browser: Do I need to just use https or is it a more complex process?

Thomas Pornin

13:29

@LucasKauffman You know, these cods and tunas can be nasty. Many US citizens own and carry firearms to protect themselves from even less probable threats.

@JeffFerland It is Dan Boneh's course. You can trust Dan Boneh for both understanding and teaching crypto.

vignesh4303

13:54

is it possible to find ipaddress of people while chatting using nmap?

Terry Chia

@vignesh4303 no

vignesh4303

@TerryChia then there is any other way?

some websites say that we can listen to netstat of windows

netstat -an command of windows wil result in foreign addresses and connected ports

is it possible to trackdown the ipaddress

Lucas Kauffman

that depends if you are using a relay server or not

and what chat protocol you are using

irc, xmpp,

Thomas Pornin

In many chat systems, each client is talking to a central server, not to each other.

The central server knows the IP addresses of everybody.

The clients know only that which the server tells them.

Some chat systems which allow "video calls" try to do direct client-to-client connections, and you can plausibly learn quite a lot that way.

vignesh4303

@LucasKauffman for eg dmz using irc clients right?

@ThomasPornin sir, well normally servers will encrypt data while chatting?

lynks

14:09

@vignesh4303 what is your situation? what are you trying to achieve?

Thomas Pornin

@vignesh4303 It really depends. For instance, the chat system we are using appears to use plain HTTP, without any encryption

And encryption has little to do with IP addresses anyway.

lynks

@vignesh4303 encryption provides confidentiality, not anonymity

vignesh4303

@lynks i need to achieve to find ipaddress while chatting

Thomas Pornin

mmh, does not work

vignesh4303

@ThomasPornin :)

brb soon to discuss

Thomas Pornin

14:13

Ok, now I have all your IP addresses.

lynks

yeap you do

well, you have my building's ip :P

Thomas Pornin

I wonder if we could do fun things with SVG (an image format which can embed Javascript code)

lynks

new idea: post an embed of a large image hosted on someone elses site to a busy chat service that supports inline imaging, instant bandwidth-DoS

@ThomasPornin interesting, objective is to kick someone else from chat without using admin tools, race ya :P

Thomas Pornin

@lynks Unfortunately I have some AD servers to deal with at the moment; I can only afford idle banter, not some in-depth hacking.

vignesh4303

adservers?

Thomas Pornin

14:21

Active Directory

also known as: work

lynks

@ThomasPornin I, likewise, really ought to be fixing the latest chunk of server app code.

vignesh4303

normally so its possible to find ipaddress of chatting person

its conclusion?

can i post this as question se site?

lynks

@vignesh4303 it entirely depends on the 'chat' application. anything that uses p2p will yield IP addresses of connected parties, a server-based chat like IRC would not.

Thomas Pornin

@vignesh4303 You do not have to ask for permission before posting; at worst, your question will be migrated or hammered.

I suggest you narrow it a bit: it really depends a lot (an awful lot) on the actual chat system

(protocol, server...)

lynks

the other option (as Thomas has demonstrated) is to use out-of-band stuff, like posting an image which our browsers automatically fetch :P

vignesh4303

14:25

i am a noob can breif a little for me?

@LucasKauffman @ThomasPornin

Terry Chia

There was a large fuss over this matter a few months back if the regulars remember.

vignesh4303

@TerryChia you mean andrew?

Lucas Kauffman

also

1

Q: A Security Stackexchange CTF team

So I'm participating in my first CTF at the moment, the biggest challenge is getting a good team together. CTF's contain multiple challenges which are often too much for one, two or three people. So I was wondering if people were interested in forming a Security Stackexchange CTF team. Nothing ...

discussion

we need at least ALL THE @Rory s !

Terry Chia

@vignesh4303 yup

@LucasKauffman heh, what would be involved? seems interesting enough.

Lucas Kauffman

@TerryChia hacking stuff, it's pretty cool and you can learn a lot

the thing is you can't do these on your own you need a team, this enables you to learn from others

and at the same you can contribute to the group

atm 29c3 ctf is being held you can have a look at the challenges

it's pretty neat

Terry Chia

14:38

@LucasKauffman you don't say :P

no time to look now, it's an online challenge?

CodesInChaos

Lucas Kauffman

@TerryChia yea

but I am playing with a guy that's been doing CTF for 2 years now

he says it's pretty hardcore

Terry Chia

@LucasKauffman ahh, count me in if you wanna have me. i doubt i can help much though as my skill levels definitely isn't on par with you guys. :)

CTFs are always fun though.

lynks

@LucasKauffman if you're compiling a mailing list, ill throw you an email :D

Lucas Kauffman

@TerryChia I don't consider myself a pro, I'm slacking with these guys

but you learn a lot really fast

plus you can always check the solutions after the competition

Terry Chia

14:55

@LucasKauffman heh. count me in if you ever form a stackexchange team then. :)

Lucas Kauffman

I will call it the a-team

@RoryAlsop go buy cigars!

Terry Chia

15:45

Ahh, I just kicked @RoryAlsop to #3 on the hat leaderboards. :)

Rory Alsop

@TerryChia dammit - that's what I get for being away from a keyboard for 5 days - have just been on my phone!

congrats

at least I have 113 hats SE-wide :-)

Terry Chia

I might be able to get the 500 view question one, but I doubt I can beat poly.

Lucas Kauffman

anyone aware of a recent problem with apache, php or ubuntu that might give you the identity of a remote client?

lynks

16:00

@LucasKauffman define 'you' and 'identity'

Lucas Kauffman

@lynks let's say I have a guy with an ubuntu server running apache 2.2.22 with php 5.4.6

he has a website with a bad session key generation

part of the session key is the the md5 hash of the ip of the user when he registered

now I want to try and get the ip of the user logged in to website as admin

this is all legit btw

before I suddenly get banned :p

lynks

interesting...

but no, you're gonna have to get the IP via some other method, post an image hosted elsewhere on the system and see who visits it :)

Thomas Pornin

16:17

@lynks Oooh, but who would do such a fiendish thing ?

lynks

@ThomasPornin i know its truly despicable, but there are some evil people out there...

David

17:03

morning everyone!

lynks

17:15

@ThomasPornin /hides

jokoon

guys, is there a way to remove a rootkit from a EFI, macbook pro ?

lynks

@jokoon the rootkit is in the EFI?

Thomas Pornin

@jokoon Nuke from orbit. It's the only way to be sure.

jokoon

i've just read articles, apparently now it can

thomas can't I just reflash it ?

I just f****** reinstalled OSX and it's still there, rkhunter show many warninigs

still shows those warnings

lynks

UEFI has a whole bunch of capabilities, UEFI malware is scarey, you would have to shred the whole drive, as in every sector.

jokoon

17:28

so EFI is not a chip it's on the hard drive ?

lynks

as far as i am aware, EFI is a partition on the HDD yes.

jokoon

so nuke from orbit

what does it mean, remove all partitions ?

lynks

how did you manage to get a mac efi bootkit!? thats like getting herpes and aids in the same day.

jokoon

even my restore partition ?

I did not

Thomas Pornin

@jokoon Well, nuke is nuke

Everything you keep can be a vector for the infection

lynks

17:32

@ThomasPornin qft

jokoon

I only installed bootcamp

today I ran rkhunter, found many warnings

so I just formatted and reinstalled

thomas: yes except jpg mp3 and avi on my usb drive

problem is, I don't have any mountain lion dvd

i'm losing faith in computers :(

I just want to go back coding my game goddamnit

Thomas Pornin

Dammit, when you install a french version of WIndows 2008R2, Administrator is not called Administrator, but Administrateur.

lynks

@jokoon you will need to get hold of trusted installation media

@jokoon but even then, if you really do have a bootkit, you will need to delete and rebuild the EFI

jokoon

you mean an USB installer ?

I don't have a bootkit

you mean a custom booter ?

is bootcamp a bootkit ?

lynks

@jokoon no a bootkit is a rootkit that lives in the bootsector

jokoon

17:40

and how do you rebuild an EFI ?

do they do that at an apple store ?

lynks

@jokoon yeah they will be able to provide you with an installation dvd

jokoon

lol I wish I could threaten the guy who has my bootkit to uninstall it, to save me the pain of reparing it

okay

I also wish they could make faster spywares, they takes so much resources

impossible to not notice them

can't use xcode with them

I don't give a sh about getting spied

lynks

@jokoon bottom line: delete everything on the disk, all partitions, and start again. The installation dvd will be able to rebuild the EFI.

jokoon

lynks thank, but I'll only be able to see an apple store in 5 days

it's amazing how the success of apple brought so many virus and stuff

lynks

@jokoon switch to a free OS and you could just download the installation disks :P

jokoon

17:45

in so few years

lykns yes, I think it's time, maybe archOS

archlinux

which one is better

debian I guess

Honestly, I got a mac because I had a MSI laptop who would randomly just shut down

I thought "apple hardware might be better"

I hope debian won't overheatt my macbook though

lynks

@jokoon 'which distro' is a very old and unanswerable question. everyone will just tell you to use their own, which in my case, is debian.

Thomas Pornin

@jokoon It is good hardware, but expensive. It has a rather low quality-to-price ratio.

@jokoon It depends on the level of hardware support. Recent distributions (or recently updated distributions) will probably fare better.

Anyway, booting on a Linux live CD/DVD will allow you to wipe the harddisk efficiently

(dd if=/dev/zero of=/dev/sda bs=512)

jokoon

bs=512 ? bootsector ?

lynks

nothing beats a good hard drive shredding on a rainy afternoon

@jokoon block size

jokoon

well I ain't many money

Thomas Pornin

17:52

@jokoon bs is "block size". It means that dd will do the write by increments of 512 bytes, which is the size of a harddisk sector

although recent harddisks use 4096-byte sectors

It won't change much. Just don't use bs=1, because it would make the whole thing rather slow

jokoon

shouldn't I use 4096 then ?

Thomas Pornin

The kernel will aggregate the write calls together anyway

lynks

@ThomasPornin i usually go for 8M or even 16M, is that bad? I assumed the system calls would slow down the whole thing if i used tiny blocks.

Thomas Pornin

@lynks A syscall is about 500 clock cycles, so you can make many millions of these per second. It won't be a bottleneck at bs=512 (it would, at bs=1).

Using bs=512 is just a way to make sure that there will be no "partial write" at the end of the disk

lynks

@ThomasPornin rgr, makes sense

Thomas Pornin

17:56

it does not matter much. It would matter (just a little) for reading the disk, precisely because of the partial read at the end

lynks

@ThomasPornin i always believed dd did a partial block if required, this is worth googling...

Thomas Pornin

@lynks I had trouble once, but this was with SunOS 4.

lynks

@ThomasPornin i guess its easier just to be safe.

Thomas Pornin

This is irksome: Microsoft's page states that Windows 2008r2 is available in several languages, but when I click on "get started now", it asks no question and sends me the French ISO. I have configured my profile to use US English, and my Web browser also sends en-US as first language.

jokoon

thomas so why go for block so small ?

Thomas Pornin

18:02

@jokoon It works, and it cannot not work.

Seems like a good enough reason to me.

jokoon

btw can I use a bootable usb key on a 2009 macbook pro ?

cant you explain why ?

Thomas Pornin

@jokoon support.apple.com/kb/ht1948

@jokoon Well, I just did, so chances are that I can. See above: the size of the disk will be an integral multiple of 512, so 512 works even if dd is not smart (depending on how partial read/writes are handled). And syscalls are fast enough to make 512-byte read/writes not an issue.

jokoon

you there aren't rootkit on linux ?

you sure*

Thomas Pornin

If the rootkit manages to infect a Linux booting off a live CD, then your machine should be cleansed with fire.

It would mean that the rootkit leaves in some flashable memory, not on the harddisk

at that point, you could consider yourself totally hosed, and you might as well just give up.

jokoon

well how should I burn the cd then ?

Thomas Pornin

18:07

ah, you do not have another computer available ?

jokoon

there's a windows 7 in the house

I could trust it

Thomas Pornin

You have to start somewhere

jokoon

but can the debian live cd also wipe the EFI ?

Thomas Pornin

A dd on /dev/sda wipes everything which is on the disk

that's the point of the thing

jokoon

so there is no bios

hum

how does my mac boot then ?

Thomas Pornin

18:09

the BIOS or whatever has this role on a Mac, lives in some ROM or Flash memory

jokoon

so there's a bios on macs

Thomas Pornin

if the rootkit is in that then you would have to reflash the thing, and the rootkit would probably defend against that; so that's flashing externally

with a soldering iron

There must be a bit of boot ROM somewhere in the computer. Macs used to rely on OpenFirmware, a kind of BIOS which included a Forth interpreter

I don't know for the modern Macs, which are kinds of PC

jokoon

"If the rootkit manages to infect a Linux booting off a live CD, then your machine should be cleansed with fire." is this possible ?

Thomas Pornin

Theoretically, yes.

jokoon

can they do it at a apple store ?

Thomas Pornin

18:13

I doubt they would do that over a counter

jokoon

I saw they have some kind of lab

Thomas Pornin

but they might recognize the issue (if that's the case) and offer a standard swap

jokoon

in the background

warranty is expired

I was just wondering if it's more secure to install nix with an usb stick or with a CD

lynks

@jokoon from a CD, as that is read-only, although the difference is negligible.

jokoon

18:34

Thomas I really doubt it could install itself in the firmware, when reinstalled OSX I did not wipe out my EFI

Thomas Pornin

19:06

"This name contains a word that is not allowed"

Dammit, Microsoft, I know my own name !

lynks

@ThomasPornin during an install? you have to be joking

Thomas Pornin

@lynks It is for creation of a "Windows Live" account

lynks

@ThomasPornin ahh, thats slightly more acceptable. rather unfortunate for you though.

Thomas Pornin

I should sue them

also, they have a "sign out" button which does NOT sign me out

I find this disturbing

lynks

i have wholly given up on all things microsoft

Polynomial

19:18

bought myself some RGB LEDs, turns out they're retina-destroyingly bright.

Thomas Pornin

ah, success. For some reason, I have unlocked the download of an English version of the Win2008r2 ISO

Polynomial

and I made the mistake of testing 4 of them at once.

Thomas Pornin

@Polynomial You know that they now sell nifty devices with four millions of little lights which you can light independently of each other ?

I have one hooked behind my computer right now./

Polynomial

@ThomasPornin You mean a screen?

:P

Thomas Pornin

I knew there was a simple commercial name for it.

lynks

19:21

that reminds me, i need to build a railgun

Polynomial

@lynks Tried that once. It's not as easy as you might think.

lynks

@Polynomial i've heard an array of camera flashers works fairly well

Polynomial

I built my own, but yeah.

you need something to kickstart it first

lynks

what did you use for the 'rail'?

Polynomial

timing is the difficult part, especially if your initial firing mechanism doesn't give uniform ejection speeds

got a plastic pipe and cut it into three ) shaped pieces, so it was like turning it inside-out

then ran the metal ball down the middle

gives closer access to the magnets

lynks

19:24

nice

Polynomial

I got muzzle velocities of about 10m/s, but that's pretty poor.

plus the barrel had to be way too long to be portable, and it cost a lot to run

Thomas Pornin

@Polynomial Usain Bolt runs faster than that

Polynomial

@ThomasPornin indeed.

sucked, especially considering my firing mechanism should have given me ~12m/s anyway

lynks

im thinking smaller scale :P

Polynomial

timing it anything faster just resulted in the last few coils not being hit properly

lynks

19:26

i think hooking it up to a degausser is the way forward

Polynomial

hehe

I'd love to do something with a donut-shaped barrel

so I could run it up to incredibly high velocity in the barrel, then remove one corner mechanically and have it eject

lynks

see if the guys at CERN will let you throw in a couple of BBs :P

Thomas Pornin

20:21

When I install Win2008R2, French version, in a virtual machine, the OS infers by default that my time zone is EST. If, on the same virtual machine running on the same host, I install the English version, the OS infers Pacific Time.

Which means that, from the point of view of Microsoft, English-speaking people are naturally Californians (or inhabitants of Seattle) while French-speaking people must be Quebecois.

Someone should tell them that European countries really exist.

CodesInChaos

I installed windows with the language set to english but the culture to german

Most of the programs display a German UI, but some an English UI

Polynomial

22:04

Welcome to the wacky world of localization.

CodesInChaos

I prefer using English, but things like AM/PM time display or imperial units must be some joke

Polynomial

I don't know anyone that uses imperial units in their OS.

the only ones I use are pints and miles, everything else is metric.

CodesInChaos

Some websites start using miles when I set the culture to en-US

I'd like a en-SANE culture

Polynomial

it amuses me that most Americans deride the British for being "old fashioned", yet we're the primary proponents of the metric system.

the only reason we use pints is because of alcohol

and the only reason we use miles is because all of our road infrastructure and law is built around it :P

CodesInChaos

Don't road signs use yards for some things?

Polynomial

22:15

yes.

I have no idea what a yard looks like.

CodesInChaos

like a wannabe meter

Polynomial

I'd guess it's about 65cm or so.

CodesInChaos

90 cm or so

Polynomial

ah, fair enough.

so 100 yards is about 90m.

CodesInChaos

A google says 0.9144m

yard=starved meter

Polynomial

22:17

yeah. so it's basically a slightly smaller meter :P

apparently it's defined as 36 inches

whatever that means.

rather amusingly, my fiancé has no idea how big feet and inches are, since she was never taught them - everyone uses meters these days.

CodesInChaos

foot~1/3 m, inch 2.5cm or so.

Polynomial

I know

1ft = ~30cm

CodesInChaos

inches are for monitor sizes

and that's about it

Polynomial

I do find an inch a useful measurement for describing things - they tend to align reasonably closely to most small objects.

like a 2p coin is a bit less than inch in diameter, a golf ball is just over an inch in diameter, a credit card is about 2x3 inches, etc.

saying 2.5cm or 5x7.5cm just doesn't quite convey the same thing.

bah. the girl who was gang-raped in India (the incident that started the protests) has died in hospital.

Thomas Pornin

22:45

@Polynomial For that matter, when Canada switched to metric system (about 40 years ago), they replaced all the road signs.

Polynomial

heh

Thomas Pornin

United States is one of the three countries who do not define the metric system as the legal basis for their measures.

All the other 190 countries (plus the dozen or so of non-UN-members countries) are on the metric system.

Gilles

@ThomasPornin I thought Liberia had switched recently

jrg

i never said the US was sane.

Gilles

apparently not

Thomas Pornin

22:48

@Gilles They did ? Finally some sense. Myanmar is next.

Gilles

@ThomasPornin that's a bit misleading: the US units are derived from SI units

Polynomial

@Gilles How so? SI units are metric.

e.g. SI unit for temperature is C/K, yet the US uses F.

Gilles

@Polynomial 1 inch is defined as 0.0254m, and so on

Polynomial

ah, well yeah, but that's a definition of another unit.

Gilles

these aren't in common use, but the definition comes from the SI

Polynomial

22:54

so it doesn't really count - it's just a way of defining a conversion to SI, rather than a definition of the unit as SI.

Gilles

°C isn't SI either

Polynomial

K is SI, but technically °C is the same unit, not the same scale.

and it is an SI unit for atmospheric temperature, iirc.

Anonymous

23:37

Hi all

Transcript for