Want to share your Wi-Fi like Bruce Scheier? Here's how (and no, its not by leaving it open).

I have been giving Bruce Schneier's article about leaving his wireless network open a lot of thought lately. Although I agree that its great to help out your neighbours there are just too many risks to leaving your Wi-Fi open. Paul from Pauldotcom raises very good points to which I wholeheartedly agree. Why risk leaving it open? It is analogous to leaving your sugar on the curb in-case a neighbour might run out. Obviously you could end up without any sugar at all and perhaps even in the worst case end up with something other than sugar in your food. The world can be a strange place.

In South Africa we routinely have people asking for help at our homes, they come in all shapes and sizes and I normally eyeball them and unless they really seem like bad apples I normally help out with a little food or money. I use my gut to judge the character of the individual.

Now, if I wanted to I could just always leave some money and food on the curb or in a publicly accessible place, but I'm afraid that that system might get very easily abused and leave the souls who really need my help with no help at all.

Ok, so what about Wi-Fi? I think that open wireless network are just silly, due to abuse, threat and possible liability. However, I do agree with Bruce that its nice and neighbourly to share. "Sharing is caring".

My proposal?

Set your SSID of your Wireless router to something that indicates your willingness to share, for example: "22 1st street for access" or "Text 5551000 for access" or even "Contact B. Schneier for access". Be creative as there is a limitation to how many characters your SSID can be.

In the case of a neighbourhood one can assume that your friends will be able to track you down and phone you for a password, you might prefer "authenticating" or making a "gut call" on all people you let in, but you can still broadcast your willingness to do so - while keeping your Wireless router encrypted with WPA encryption and a good password that you can change after a reasonable amount of time or when you feel that your goodwill is being abused.

This seems to me to be a "best of both worlds" solution. What do you think?

Steal This Wi-Fi

A very interesting, thought provoking, article by Bruce Schneier.

Security is all about tradeoffs, you can choose never to participate in dangerous activities like flying or driving a motorcar but most of us choose to assume the risk.

w00t

I am very pleased to report that some feedback I sent was featured on the Security Now! podcast.
There are some podcasts that I make a genuine effort to keep up with and a lot of those come from Leo Laporte's brilliant TWiT network.

Just search the shownotes of show 124 for "Stephan Buys" to read my suggestion regarding private browsing by manually managing cookies in Firefox, alternatively listen to the audio also provided through the link or subscribe to the show using iTunes.

Mac OS X Open Source and Security

Previously I blogged about my regularly used Open Source applications on the Mac. Today I am dealing with some applications that deal with security on the Mac. In my career I wear two hats, one of Open Source advocate/developer/consultant and then also a security consultant hat.
I also have a keen interest in keeping my Mac secure when using it from day to day - thus the tools I am about to discuss deal with "personal" security (local firewall for example) as well as "network" security.

Lets get started.

1. MacGPG (http://macgpg.sourceforge.net/)
• The Free Software implementation of PGP. I specifically use the GPGMail plug-in for Apple Mail.app to allow me to send and receive encrypted email as well as sign emails and verify email signatures.
  
2. sshfs (http://code.google.com/p/macfuse/)
• A FUSE pluggable filesystem for the Mac that allows it to mount drives on other Unix or Linux hosts using ssh. This might not be a specific security related app but it does allow for extra security when sharing across a network - the links are encrypted and safe from snooping.
  
3. Waterroof (http://www.hanynet.com/waterroof/)
• A personal firewall manager that exposes the underlying, powerful, ipfw firewall of Mac OS X. There were a couple of scares with the Leopard firewall's default behavior when it first ship and it led me to look for more information on the topic. Waterroof allows a user to truly fine-tune the firewall. A handy wizard also allows novice users to set up a very secure default policy.
  
4. MacPorts Apps (http://www.macports.org/)
• Some applications are best served using macports. To install the following app download and install macports and then issue: "sudo port install appname"
  
1. nmap (http://insecure.org/nmap/)
• nmap is the de-facto standard when it comes to port scanning. You can use nmap to learn a lot about hosts, networks and services.
  
2. wireshark (http://www.wireshark.org/)
• wireshark is a packet sniffer with a lot of advanced capabilities. Packet captures can be analyzed to a great level of detail. It also produces traffic flow and usage reports on the traffic that it captures. If you need find out what is going on on your network you need Wireshark.
  

Thats it for this installment. There are many more apps within MacPorts that I'm not covering here, as well as some legendary apps like KisMac. I will try to blog again soon about some more Mac OS X Open Source goodness. As always comments are welcome and if you know of any other great OSS security analysis tools on the Mac please let me know.

WEP?? Leopard Internet Sharing Woes

I anxiously awaited Leopard in the hope that Intenet Sharing would support WPA. I have a really hard time understanding why Leopard supports Internet Sharing through WEP. Aircrack-ng and other tools can crack WEP in uder a minute - it just does not make sense.

Perhaps the Lazyweb can recommend a solution whereby I can do WPA through third party support? From what I understand WPA has the same performance impact as WEP (when not using AES) - but it probably is a case of the Hardware only supporting the old standard...

My recommendation? If you truly need to do Internet Sharing do it through the Ethernet port (using a crossover cable) or enable WEP only for a short while and change the password every time you use it.

Leopard Firewall - OS X 10.5.1 relief

I'm glad to report that this morning after updating to Mac OS 10.5.1 the firewall seems to be working as advertised. They dropped the "Block all incoming" moniker and replaced it with "Allow only essential services", which I selected.

Also, I enabled "Stealth Mode" under Advanced.


I then ran some tests from another host to verify that the firewall was up and it seemed to be performing as advertised. I'm pretty interested to see what the "Essential" services are - perhaps I will do some digging soon.

Just for completeness run the following tests from another host on the network:
$ ping hostname
(Should return no replies if stealth is on)
$ nmap hostname
(Should also not return with any open ports)

I disabled my firewall temporarily to scan for some open ports and then tested connections to those ports using telnet after re-enabling the firewall. All results were also positive.

I'm very pleased that this issue has been resolved.

Leopard Firewall Woes

I have been using Mac OS X Leopard for the last few weeks and the article on Heise Security caught my attention. I use a 3G connection to the internet quite often and have to assume that a NAT firewall wont always be available.

I did some of my own tests and as far as I could tell setting the firewall to "Block All Incoming Connections" just does not seem to work.

The output of "sudo ipfw list" does not seem to change when switching between "Allow All" and "Block All"...

Here is what I recommend for now:
- Download WaterRoof ipfw at: http://www.hanynet.com/waterroof/ (its OSS).
- Run through the Wizard, just clicking next is the equivalent of "Block All"
- If you want "Stealth", go to "Static Rules" and add a rule to block all ICMP from "Any" to "Me".
- Make these changes permanent through: Tools -> Startup Script -> Install Startup Script.

To test if your setup is any good head over to Shields Up! Steve Gibson's excellent resource and run some tests to check that your firewall is actually working as planned. Shields Up! can be found at: http://www.grc.com/.

Please note that this test is most effective if you are directly connected to the internet. If you cannot connect directly rather Google for nmap and run some tests on your LAN. I used nmap to run some tests against the firewall to confirm the results - consider just trying to ping your machine from another host at least.

For reference here are my rules, running "sudo ipfw list" from the terminal should give you similar results.

$sudo ipfw list

00100 allow ip from any to any via lo*
00110 deny ip from 127.0.0.0/8 to any in
00120 deny ip from any to 127.0.0.0/8 in
00130 deny ip from 224.0.0.0/3 to any in
00140 deny tcp from any to 224.0.0.0/3 in
01000 allow tcp from any to any out
01000 allow tcp from any to any established
01100 deny icmp from any to me
65534 deny tcp from any to any
65535 allow ip from any to any

And remember: "Friends do not let friends get Owned" - Pauldotcom Security Weekly

You should read this if you use Facebook

Sophos Facebook best-practices

7 Actions to browse the Internet a little safer

My 2 cents worth regarding a safer browsing experience, I am ordering these from easy-to-do to really-paranoid and hard to set up.

1) Use Firefox
(http://www.mozilla.com/en-US/firefox/)
2) Disable "Remember passwords for sites" in
Edit -> Preferences -> Security
3) Clear you private data when you close Firefox
(Edit -> Preferences -> Privacy -> Private Data. (I clear all private data on logout without Firefox prompting for permission)
4) Disable JavaScript
(https://addons.mozilla.org/en-US/firefox/addon/722)
5) Use strong passwords
(https://addons.mozilla.org/en-US/firefox/addon/469)
6) Browse inside a Browser Appliance
(http://www.vmware.com/vmtn/appliances/directory/browserapp.html)
7) Browse using a LiveCD
(http://www.ubuntu.com/getubuntu)