Information Security

From 35C3 Wiki

Feel free to edit/update this page if you see anything outdated!

Also, as usual and as this is a wiki, do not trust everything blindly.

Introduction

The annual Chaos Communication Congress is a huge event with people from very diverse backgrounds. If not just the fact that this environment is largely driven by curiosity, an event of this size makes it inevitable that there are indivduals with less noble motives.

This makes it advisable to take extra care in securing one's own equipment and also paying attention to the stuff around oneself.

If you don't feel comfortable or competent enough in doing so, please consider leaving your devices (laptop, smartphone, etc.) turned off. After all you might be there because of the people, who, in turn, might be able to help you learn how to secure your devices (e.g. CryptoParty assembly).

There are many ways to gain access to a system, physical – including theft and bad usb devices – and remotely over the network where the possible security holes are manifold – be it different services running on the machine, the sniffing of passwords and other data of the wired and/or wireless network or the active distribution of malware by social engineering or phishing attacks:

closing/securing open ports/services

http://www.williamhpeters.net/syb_eng.png


How do I know, what services are secure?

Tools to find out what services are running

  • netstat -tulpen (Linux, Windows, Mac)
  • lsof -i -P
  • ps (Linux, Mac)
  • nmap -p- localhost (Linux, Windows, Mac)
  • fuser (Linux)
  • Network Utility (Mac)
    • filemon
    • Regmon
    • TCPmon

Disabling services in Windows / Linux / Mac (/ other *BSD)

  • Linux (System V style init)
    /etc/init.d/$service stop or /usr/sbin/$service stop
  • Linux (systemd, system and service manager)
    systemctl stop $service
  • {Free,Net,Open}BSD and others (RCng-style init)
    /etc/rc.d/$service stop
  • Windooze
    '/ Start / Systemsettings / Services' -> Properties of service -> Stop
    If you want to make sure that the service stays stopped then set the Startup Type of the service to 'Disabled'
    Good documentation about disabling services in windows (only german?) http://www.dingens.org/ && http://www.ntsvcfg.de/
    Another (detailed) documentation on how to disable unnecessary windows services: http://www.hsc.fr/ressources/breves/min_srv_res_win.en.html
  • Mac (OS X)
    Go to System Preferences -> Sharing -> Services and uncheck all the things you don't need running. On the second tab you can also enable your firewall (which would be the 'smart thing' to do).

Physical Security

Introduction

What good is a secure operating system, if the computer it is running on is rebooted or stolen? With one 40Mb boot CD all your security measures may be ignored.

Prevention of theft

When a laptop or harddisc is stolen there is a financial damage through loss of hardware. But often the loss of data is much bigger when there is no backup. And then personal, classified or business data will then be in the hands of the thief.

What you can do:

  • Backup your data before going to 35C3
  • Encrypt your hard disk
  • Label your hardware:
    • Put your name and cellphone number on it, so anyone can check whose hardware it really is.
    • Put stickers on it. This usually makes it a unique piece.
    • If you're scared that others might see your real name or that if stickers get lost: label phones and laptops inside the battery compartment.
  • Set a BIOS password.
  • Encrypt ALL the disks
  • Backup your data.

Also, as a side note: Please make backups of your data.

Labeling at the 35C3

There is no service of hardware labelling at the congress anymore – so be with friends and make sure your hardware is watched at all times!

The insecurity of locks

Lockpicking is part of the 35C3 program. Even if you don't know how locks work, you can learn how to pick them in a couple of hours.

Do not trust the security of Kensington products! These are only a partly effective simulation of security, which can not stop thiefs who can cut cardboard.


Being prepared, in case shit happens

But if you take other variables, for example the normal "Verpeilungsfaktor" (german, "mess-up factor"), into account, you should always assume that it is possible that your computer or your data get lost. There is no such thing as a absolutely secure system! (Also every system needs regular care in terms of security updates etc.). Accidents happen.

Therefore you should as a matter of principle make a backup of all important data! Additionally it is important in case of theft to note down all your serial numbers in advance somewhere (especially of your hard disk, using hdparm -I, because data thieves might only steal your disk) if they are not already on your hardware invoice (which you should have available if you should need to contact the police).

The most simple rule for decent security is: Never lose sight of your laptop. The best thing is to carry it around with yourself all the time (greatly increasing the ability to take notes during lectures as a side effect). In addition you can as well ask trustworthy persons to guard your (portable) computer. This is especially useful if the box is hanging hard wired on the network, transfering large files, while you rather want to go to a lecture.


What to do if your equipment is gone

First of all, don't panic!

Check the area around you, sometimes people put equipment under the desk or shift it to the next desk and/or it may get buried under lots of other stuff.

If you can't find it, ask the people around you and ask your friends, maybe someone put the equipment in a safe place for you.

Check Lost+Found at the Ministry of Information. If your hardware was labeled it might happen that they contact you!

If the equipment is still missing, please contact Static:Safety_and_Security via DECT 110. They will clarify the next steps, e.g. complaint of an offence at the police to possibly get the money back from an insurance company, check the outgoing equipment at the exits of the 35C3, search for it in the whole building, note your contact details to check if your equipment popped up at the end of the congress as "lost+found" stuff, etc.

Check Lost+Found afterwards!

BIOS-Password

In order to ensure that nobody can break your password barriers with simple physical access, for example by booting a Knoppix live CD or something like that, you should prevent that directly in the BIOS. To do this, configure your BIOS to allow hard disk boots only and protect this setting with a BIOS setup password.

Some more or less smart people can in individual cases (insecure BIOSes) still boot from other media. Therefore we suggest (at least for the time of the congress) to set up a general boot password in the BIOS.

Note
In this text we will assume that you already know about password security (e.g., don't use passwords like "root", "$PASSWORD", "GoGetNaked", "hackme", "Jenny" or "Oak"...)

Macintosh Computers

Set an Open Firmware Password: https://support.apple.com/kb/HT1352

Please note that this also applies to Intel-based Macs although they're using EFI.

Bootloader configuration

As another security measure you should take care that it is not possible to override the normal boot process by adding init=/bin/bash to the kernel parameters in your (Linux) boot loader. This would fire up a bash with root privileges and even without a prompt for the root password.

This step is very important! You can as well configure it so that you are only asked for the password if you want to add special parameters.

LILO security

To configure LILO for using a password, edit the /etc/lilo.conf: 

 password=""

If you want to be prompted at boot, if you try to append stuff to the kernel: 

 restricted

start /sbin/lilo -p and provide the password you want to use. It will be stored in /etc/lilo.conf.shs (or something)and gets encrypted.

If you want to use special characters, you have to change the heyboard layout: 

 /usr/sbin/keytab-lilo.pl de > /boot/de.ktl

and add the following line to /etc/lilo.conf: 

 keytable = /boot/de.ktl

GRUB-Security

First you should create a password using /sbin/grub-md5-crypt, which is returned as an MD5 hash. Then you add in GRUB's configuration file /boot/grub/grub.conf the line "password --md5 <hash>", replacing <hash> with the password returned by grub-md5-crypt.

If you require a more secure hashing algorithm, you can use /sbin/grub-mkpasswd-pbkdf2 and enter a chosen password. It will return a hash, starting with 'grub.pbkdf2.sha512', then edit your /etc/grub.d/00_header file, to include the following: 

   cat << EOF
   
   set superusers="root"
   password_pbkdf2 root <hash>
   
   EOF

Where the hash is the string starting with 'grub.pbkdf2.sha512.10000' returned from the '/sbin/grub-mkpasswd-pbkdf2' command.

An additional "lock" will make it necessary to enter the password everytime you want to start an image. You should use this, if there are "other" operating systems available on your computer which don't have privleges management. They could be used to override your protection.

Access control for the running System

Leaving a running system unguarded is a big risk for the security of your system.

  • Always lock the screen / log out of your session
  • Never leave an open rootshell

If your desktop environment does not have an obvious "Lock screen" or "Log out" feature, you can use programs such as "vlock" or "slock".

If you don't want to take your equipment with you everytime you go to take a leak, you should definitely, before handing your box over to others to guard it, close or lock all sessions.


These measures still don't protect you from attacks against hardware components as e.g. the usb, network or firewire ports which could be used to autoexecute code or even read out the computers memory.


Passphrase security

Use strong passphrases _everywhere_. Never use the same passphrase twice. Never let people see you passphrase (lower your laptop lid while typing it, sit with your back against the wall, ...). Depending on who you defend against, don't type in your passphrase while your laptop is hooked to the powerline.


Saving your data from others, deletion or yourself ;o)

If you want to be sure that one cannot access your data if your hard disk gets stolen, you can for example use dm-crypt to encrypt your hard disk or single partitions (e.g. /home, /tmp and swap). You can find links to the "Disk Encryption HOWTO" and the "Encrypted Root Filesystem HOWTO" below under "Additional Information".

For Mac OS X there is an option called FileVault in the system settings, which cares automatically and transparently for encryption (which means: you just have to check a check box).

Checklist

  • Set BIOS-Password (at least setup password)
  • LILO/GRUB-Password (at least restricted!)
  • Password security (characters, non-trivial, etc.)
  • Never leave a rootshell open!
  • Backup all important data!
  • Watch over your hardware, or ask someone trustworthy to do so
  • Think of more access control
  • Encrypt your hard drive and usb sticks.


Surfing

  • Don't use Internet Explorer, but Firefox or Chrome/Chromium instead.
  • Uninstall Flash (and leave it uninstalled, you don't need it for nothing).

Assume that there will be many people at the congress who try to exploit security holes in e.g. Internet Explorer. Firefox is not rockhard secure, but it is a much better bet, than IE.

Something about encryption on the web: On an encrypted and authenticated site, Firefox displays a closed padlock to the left of the address bar. Locks may appear elsewhere, and many websites put them inside the webpage, but these are useless and should be entirely mistrusted. Besides a lock, also watch for the domain. By default, Firefox has a slight contrast difference between the domain (in black) and the rest of the URL (in grey). Despite this, make sure that the domain is followed by a slash (/). For example https://paypal.com.index.php.sessionida9c9e776d49388.tk is not actually PayPal, but https://paypal.com/index.php.sessionida9c9e776d49388.tk is.

If you are warned about a certificate error, you can either continue to the website or not continue. If you continue, the site will be equally secure to http (without s!), so all traffic may be read by a third party and all traffic may be modified by a third party. Do never ever enter personal data on unencrypted http or untrusted https websites. If you ever get these errors on websites like Gmail or other big companies, it means you are being attacked (either personally, randomly, or everyone there is being attacked). Also if you continue upon certificate warnings in Firefox, be sure to uncheck the "store exception permanently" box. You should be warned every time. If you don't, Firefox will always say it's a perfectly secure website and you might (e.g. next year) have forgotten that it was actually a security exception.

It's also recommendable to use private navigation mode or incognito mode (ctrl+shift+P in Firefox, ctrl+shift+N in Chrome) for https websites. Long story short: if you open incognito mode and only use https websites in there (and you don't get certificate warnings), that is rather secure. One could argue that it's safe enough to log in to your bank. If you open a single website with http (or a single website with a certificate warning) in that same incognito session, the security of the https websites may be partially compromised by the BREACH exploit.

If you are german-speaking, you may want to read Einfallstor Browser on heise.de

Unencrypted - HTTP

Don't give personal data, when surfing unencrypted at congress, e.g.:

  • Username and password for ANY SERVICE WHATSOEVER
  • Cookies with user/pass (if you get logged in automatically)
  • Personal data like address, name, gender, sexual desires ;o)

It could be a good idea to delete all your cookies before congress. If you need a backup of them, they are in ~/.mozilla/firefox/default/$chaos/cookies.txt (or cookies.sqlite). In preferences you can choose to be asked if a site wants to give you a cookie.

Use the SSH feature called "SOCKS port forwarding" (ssh -D) to tunnel HTTP connections through your SSH host at home. 

   chromium-browser --proxy-server=socks5//:localhost:3129

Or in Firefox you can simply set the SOCKS proxy in the preferences (see preferences->advanced->network->settings).

Encrypted - HTTPS

Encrypted connections generally have the advantage that the data cannot be read by anyone sniffing on the network, because they are transmitted encrypted to the web server. You need to take some safety measures, though:

It is possible, that others try to intercept your connection ([Man in the Middle Attack]) (MITM), by placing themselves between you and the web server to read the data in cleartext. You can prevent this by adding a static ARP entry for the gateway (NOC#SecureNet) and by not simply clicking away messages of your browser that the certificate has been changed (which is a quite clear sign). But there are some sites, which don't have their certificate signed by one of the common authorities. Therefore a warning message appears for them as well. You could load the page once before the Congress and tell your browser to accept this certificate automatically. (You may use Firefox and add a security exception, which will be bound to the specific certificate. A repeated error message at a later time may indicate a MITM attack using a different certificate.)

iStuff

Secure your iPhone:

  1. Backup your iStuff before congress. See Backing Up, updating, and restoring your iPhone,and iPod touch software. Backup your backup somewhere else, just to be on the safe side.
  2. Erase iPhone content: Tap Settings > General > Reset > Erase All Contents and Settings*
  3. Enjoy congress. Optional: remove your sim-card
  4. At the end of congress: Transfer all your data of your iPhone but don't sync
  5. Click the "Restore" button in your iTunes-iPhone page. DON'T BACKUP! DON'T!!! It may erase your previous backup, you wouldn't want that.
  6. Wait for your iPhone to reboot and restore your last backup*


* I never tried Erasing All Contents and Settings and restoring it from a backup. Don't hold me liable if it doesn't work [for you].

  • Jailbreakers should change the standard Appel mobile pw and root pw.

Change the standard Appel mobile pw

  1. Open the terminal ( you see something like "your iPhoneName": ~ Mobile$)
  2. type: ‘passwd’ (without the quotes) Your old PW should be ‘alpine’ (without the quotes), Make a new stronger pw, type this one twice.
  3. Type: 'logout'(without the quotes)

Change the root pw

  1. type ‘login’ command (without quotes) and press enter.
  2. Then type ‘root’ (without quotes) as your login and ‘alpine’ as your current root pw.
  3. Once are root, type ‘passwd’ command (without quotes) again and press enter.
  4. Enter a new password (twice).
  5. Type: 'logout'(without the quotes)
  6. done

Reading mails

Webmail

Use an encrypted connection, like described above! Otherwise, you'll have to get your password from a blackboard. ;-)

POP3/IMAP

Use SSL/TLS and check for certificate validity (see your mail retrieval agent documentation for info on how to set it up).

SSH

Use it to open a secure connection to your home PC. You can also use it to tunnel other TCP/IP connections through your home network... and be sure to know your home-servers fingerprint and authenticate with keys instead of password...

How to tunnel?

 ssh -D 1234 user@example.com

This opens a SOCKS tunnel/proxy on port 1234.

How to tunnel everything (TCP, UDP and ICMP) transparently?

The following howto has been a great help in recent years:

http://blog.crash-override.net/index.php/206 (via archive.org)

On OS X

Problem: Ensure that ALL traffic from your laptop goes over your proxy. Including apps that don't take proxy config, like Skype.

Answer
  1. ping yourserver.com; note its ip [we're going to tunnel DNS in a sec, don't want a catch-22]
  1. ssh -C2fND 9999 yourserverip
    The flags are: compressed, ssh v2 only, go into background and don't do anything on the remote other than proxy, and open up port 9999 as a socks proxy.
    AFAICT this doesn't require root on either client or server. (Real tunnel devices do, on both. I wasn't able to get a tunnel device [ssh -w any:any] working on my VPS.)
  2. install http://www.proxifier.com/mac
  3. launch it and configure in 'options' menu:
    • proxy settings: 127.0.0.1 port 9999 socks 5
    • proxification rules: add; rule name: your server name; ip range: your server ip (NOT dns); click 'add' next to IP entry; ok. Most of the fields left blank.
      • these are the *exceptions*, by default - there's a radio button to invert that. Obviously we can't tunnel the ssh tunnel over itself, which is why we're making it an exception. :-P
      • add more exceptions if you want to access something on the LAN
    • name resolution: enable

The end. It also supports proxy chaining if you want to be fucking paranoid - in proxy settings just set it up from the perspective of each successive hop.

Just tested it, works perfectly. Might have some holes (e.g. low level stuff?), but I'm not seeing anything on local iftop other than LAN stuff and incoming direct connections.

It's a lot easier to use than tsocks, and more respected than merely setting a proxy in system settings / network / proxies (which e.g. Skype ignores).

If you run plain ssh commands now, they'll first get proxied - e.g. "ssh pony.noisebridge.net" will go via the proxy without any further config. Ditto everything else that's not in proxifier's exception list.

I suggest installing (via macports) iftop or the like on both machines; it's a nice tool to watch what's happening.

Too much work.

Try https://github.com/apenwarr/sshuttle

IRC

Everything you write is blown out on the net, unencrypted. So DON'T authorise yourself against any bots/Nickserv/Chanserv etc. on the congress. If you need to authorise yourself against any service use SSL.

What should I do before coming to the Congress?

  • Make backups of everything, since you can never be guaranteed 100% security everywhere (short of unplugging your PC from the power outlet).
  • Choose your password carefully. Anything written in a dictionary of any kind is insecure, and so are easy combinations. You should never have the same password as your username.
  • Print your ticket!

Useful programs

  • Chat client: An IRC client, e.g. mIRC or X-Chat.
  • Network diagnosis: nmap
  • Ethernet configuration: dhclient / pump
  • Browser: Any decent Web browser, e.g. Firefox, Chrome, or Opera. Internet Explorer not recommended.
  • IPv6 support: (supported natively)
  • WLAN drivers
  • Wi-fi tool: Wavemon
  • Sleep: Alarm clock
  • Screensaver: Any screensaver with password locking, e.g. vlock, XLock, or Xscreensaver.
  • SSL tunneling: stunnel
  • Mac Data Recovery Software

Useful hardware

  • Notebook
  • DECT phone. Just talk to the POC
  • Cellphone
  • Coffee cup with closeable lid (save that keyboard and no wasting of coffee)
  • Junction Box for power outlets (think about the others and take more with you than you think you need). According to wikipedia, the german type is CEE 7/4, they are also compatible with the following plugs: CEE 7/7 plug, CEE 7/16 Europlug, CEE 7/17, Soviet GOST 7396 C 1.
  • If you have equipment with Australian, North American, British or an Asian (non Europlug) device, make sure to carry an adapter with you and also ensure that your device can live healthy from 230V AC at 50Hz as it is served in Germany.
  • WLAN/WiFi card using a/g/n-technology
  • Camera (but please respect other peoples privacy!)
  • USB stick
  • $Multimediatool aka geek gadget (MP3-player, PMR, PDA, bluetooth stuff, etc.)
  • Be sure to have your laptop ready for the video projector, if you will hold a lecture
  • Please tell us beforehand if you bring BIG hardware with you
  • Bring switches (100+), cables, power sockets with you!
  • Network cables are always useful
    • There are retractable network cables available, they are very handy!
  • Project documentation
  • if necessary your Chaosnumber
  • if necessary a (sufficiently convincing fake of a) document, in case we are in doubt about your age.
  • The urge for wanting to know more and more and more and.....

DO NOT

Just think of the netiquette in real life. Don't be rude, stupid, selfish and whatnot. If you have any problems, contact the Infotresen, an angel, or the CERT.

The following is just an excerpt of stuff NOT to do:

  • NO Arpstorms
  • NO Drug consumption equipment
  • NO Nasty audio equipment
  • NO Private WiFi access points
  • NO Private DHCP servers
  • NO Social hacking (don't trust anyone)
  • DO NOT use POP3/telnet without encryption
  • DO NOT use (Private) FTP without encryption
  • DO NOT take photos of others without their permission
  • DO NOT connect coffee machines (except in the coffee-rack)
  • DO NOT stick anything onto the walls
  • DO NOT stick nails, screws, etc. into the walls
  • DO NOT carry around a magnet with 2 megatesla in your pants *g* (e.g. modern computer tomographs have 2T)
  • DO NOT order food to the CCL.
  • DO NOT sleep in the CCL. Please get some Static:Accommodation outside!
  • DO NOT hack someone's bluetooth enabled phone. She or he could be outside in the queue...
  • DO NOT hack someones GSM Phone, except they are on congress-gsm.

Other Information

Secure Internet Access

If you do not have access to a trusted VPN but want to access insecure sites or services outside the congress network without being eavesdropped on by fellow hackers, feel free to use the CAcert Community VPN tunnel. Basic documentation is available on the CAcert Wiki or call / find User:Natureshadow (DECT 3128)!

Please note that the tunnel will most likely not be available this year. If you still need this very desperately, User:Natureshadow might still be able to help you!


Operating System Specific Security

*nix

Terminal access

There are tools like xscreensaver or vlock, which can be used for this. Additionally, most window managers have a special "lock session" function.

If a person has physical access to a box where these preparations have been made, i.e. there are no open sessions, there are still ways of attacking. Here you should make sure your login.defs and login.access are configured reasonably (see the man page and the commented example files).

Additionally you can limit the consoles where root is allowed to log in in the configuration file /etc/securetty. A little "security by obscurity" hint: Don't allow it on the first console, this one's going to be tried most possibly. You could for example just allow console 13; seldom someone thinks of trying it there. It should be clear that manual "brute force" logins are nearly impossible, but you never know. Maybe somebody was looking over your shoulder... (My computer science teacher always sent everybody out of the room when he was entering important passwords.)

Physical access

Another thing worth mentioning: Even when all consoles are locked and the passwords theoretically unguessable, most recent notebooks and desktops are equipped with Firewire, which can be quite a lot of fun as well: http://www.ccc.de/congress/2004/fahrplan/event/14.de.html (German only) And who knows, maybe somewhere in the RAM there's a clear text copy of the necessary password...?

Firewall

Hint: If you rely on your packet filter to block incoming traffic, do not forget to filter IPv6 as well! (ip6tables on linux)


Mac OS X

An extensive OS X security whitepaper is available from Corsaire

SnowLeopard Security Config: SnowLeopard Security Config

A little screencast in german covering the most important things can be found here

Screensaver/suspend lock

You should enable a password prompt when waking from sleep or screensaver. Do so by going to 'System Preferences' -> 'Security' and enable 'require password to wake this computer from sleep or screensaver' option. More options like 'disabling automatic login', 'logging out after a specific period of inactivity' and 'requiring a password to change any of secure system preferences' can also be enabled here.

Keychain Access

Also, you might want to prevent people from accessing your keychain (where all your passwords, from safari, IM clients, etc are stored). Start the Keychain utility (it's under Applications -> Utilities -> Keychain Access). Select the 'login' keychain from the sidebar and go to the menu 'Edit' -> 'Change Settings for Keychain "login"'. There you can choose to lock your keychain as you suspend your computer or after a specific time of inactivity.

By default, the password used to unlock your keychain is the same as the one you use to login to the system. You can change it in Keychain Access by going to the menu 'Edit' -> 'Change Password for Keychain "login"'. If you have some room left in your menubar you can also add the keychain status icon there (enable it via the Keychain Access preferences).

Pair your Mac with your Remote

Just point your remote at your IR-Receiver (mostly next to Power-LED) and press <Menu> + <Next> for 5 Seconds. (a big acknowledgement screen will appear, showing a chain and a remote control). You need to be logged on as administrator, though.

Preventing traffic when (Open)VPN is not connected

http://superuser.com/a/468955


Windows

Disable the automatic logon feature. Don`t work as admin!

If you run an Windows XP Home Edition, boot your computer while holding the Shift key and log in as "Administrator". By default there is no password for this hidden admin account: you should change this! Patch your system with the newest updates and make sure to have at least the windows firewall running.


Links


Authors

This document seems to have been originated by aleχ and Scytale.

So:

"Have fun on the Congress, aleχ (translation by Scytale)"

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