Native Apple iOS Client and Android Client to Cisco ASA VPN using Certificate Authentication Part 3 – ASA Side

So based on the last post, you can now start to configure the ASA to support Apple IOS and Andoid devices.

Firstly we need to add an IKEv1 policy to allow the IKE Phase 1 to establish:

!Andoid
crypro ikev1 policy 10
 authentication rsa-sig
 encryption aes-256
 hash sha
 group 2
 lifetime 28800

!IOS
crypro ikev1 policy 12
 authentication rsa-sig
 encryption aes-256
 hash sha
 group 5
 lifetime 3600

This allow the device to at least connect to the ASA to authenticate.

There is an assumption that your ASA already has installed and trust’s the CA’s that the client device certificates are issued by.  This is out of scope for here however its imperative that this is in place.  Its also crazy if you havent got CRL processing in place but you should know that as well.

From a ASA profile perspective its simple.  As stated before both Andoid and IOS only support IKE v1 so you have to create IKEv1 profiles for these connections.  The strange part of defining an IKEv1 profile is that is has to have a AAA entry set.   In my case I normally define a new AAA group that has no authentication.

aaa-server NO_USER_AUTH protocol http-form

This can then be applied to a new profile.  Its not used for authentication (remember – you are using Cerificates only) thus

tunnel-group IOSandAND type remote-access

tunnel-group IOSandAND general-attributes
 ! Clients will use addressing from the named pool shown
 address-pool IOSandAND-Pool
 ! Dont use any client authentication (other than Certificate)
 authentication-server-group NO_USER_AUTH
 ! Group policy applied for connection
 default-group-policy GP_IOSandAND

tunnel-group IOSandAND ipsec-attributes
 ! Define CA that client connections will be signed by
 ikev1 trust-point MyCA.key
 ! Define no user authentication
 ikev1 user-authentication none

Depending on if you use DAP etc (and you really should) you will have to add basic policy to allow Andoid and IOS devices to connect.  There are no posture checks availible for native clients due to what the clients expose.  If you want to do this then the client will need to use the AnyConnect client (free), will need a AnyConnect Mobility licence for the ASA (circa £500) and you can then use IKEv2 which negates a lot of this configuration.

Anyway hope it helps some of you

Native Apple iOS Client to Cisco ASA VPN using Certificate Authentication – Part 1

I have been working on this for a while now.  Because of a variety of reasons that I can’t go into here some of my configuration was mandatory.

The Apple iOS (used on iPhone, iPad and iPod Touch) has an in-built VPN client that Cisco assisted with development.  It supports PPTP, L2TP and IPSEC.  Unless you are crazy you would only seriously use IPSEC.  However, it only supports IPSEC using IKEv1 key negotiation.  Unless you have a specific reason really only IKEv2 should be used a it has a number of performance and security benefits.  So that causes a problem with iOS devices.

Using a IKEv1 in conjunction with a group/pre-shared key is well documented and simple to get working.  If you are using Certificates then it gets a whole lot interesting.

One fix is to use the AnyConnect client from the App Store.  This is free to download and can be deployed using the Apple Configurator utility from a Mac OSX device.  This allows SSL VPN as well as IPSEC IKEv2 connections (in version 3.0 of the AnyConnect iOS/Andriod client) and has enterprise grade tools such as logging, diagnotics and a tool similar to the DART utility that the desktop AnyConnect has.

The difficulty with this is that even though you have purchased SSL VPN user licences (AnyConnect Essentials or Premium) Cisco still want some more money in the guise of ‘AnyConnect Mobile’ licence.  These retail at around £500 but still another outlay you did not bargin for.  Also your security policy may mandate the use of the built in client so its time to roll up your sleeves.

So what’s it doing ?

As with most things, being able to see what the iOS device is actually doing would be a good start.  In Apples infinite wisdom any user messages are usually “cannot connect”, “unable to verify server” and not a lot else.

Armed with a Mac you do have a number of tools at your disposal.  Of course if you are reading this it stands a good chance you are doing this is a company and you will need a Mac to deploy Enterprise profiles to iOS devices as lets face it you really, really should lock those babies down.

1) Remember the Mac OSX VPN client is very similar to the iOS VPN client so if its possible to replicate the configuration on the Mac, you may see something more useful to start with.  In my experience you don’t but its worth mentioning.

2) Using Xcode its possible to see the iOS devices system log in realtime (equivalent of the /var/log/messages file)  From this you can see more useful messages from the client.  To do this:

  • Install either Xcode or the Apple Enterprise Configurator from http://www.apple.com/support/iphone/enterprise/  I used Xcode
  • Open Xcode, then select Window > Organiser
  • Connect to iOS device to your Mac using a USB cable
  • You should then be able to select the device then Console Log

3) For a low level view of what’s going on you can use the Mac to create a virtual interface to tunnel the iOS devices network traffic over.  From then you can use TcpDump to take packet captures.

You again need a Mac, USB cable and a utility from the App Store that you an pull the iOS’s UUID device down.  This is important.  I used UDID+ but there are others.   Quite how this will work when Apple remove it from iOS 6 is not well known…… anyhooo…..  Once you have the UDID run the following on the Mac

 $ # First get the current list of interfaces.
 $ ifconfig -l
 lo0 gif0 stf0 en0 en1 p2p0 fw0 ppp0 utun0
 $ # Then run the tool with the UDID of the device.
 $ rvictl -s 74bd53c647548234ddcef0ee3abee616005051ed
Starting device 74bd53c647548234ddcef0ee3abee616005051ed     [SUCCEEDED]
$ # Get the list of interfaces again, and you can see the new virtual
 $ # network interface, rvi0, added by the previous command.
 $ ifconfig -l
 lo0 gif0 stf0 en0 en1 p2p0 fw0 ppp0 utun0 rvi0

Then

$ sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.rpmuxd.plist

Now that you know the name of the RVI, you can point your packet trace tool at it. For example, he’s how you might run tcpdump to take a packet trace from the RVI.

$ sudo tcpdump -i rvi0 -n
tcpdump: WARNING: rvi0: That device doesn't support promiscuous mode
 (BIOCPROMISC: Operation not supported on socket)
 tcpdump: WARNING: rvi0: no IPv4 address assigned
 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
 listening on rvi0, link-type RAW (Raw IP), capture size 65535 bytes


When you’re done you can remove the RVI with the following command.

$ rvictl -x 74bd53c647548234ddcef0ee3abee616005051ed
Stopping device 74bd53c647548234ddcef0ee3abee616005051ed [SUCCEEDED]

That should get you into a position you can debug the client traffic.  Simply open the captured traffic up in WireShark and you may have a clue…….

In part 2, Ill discuss ASA configuration and what works, what does not and what is an Cisco ASA bug !

My beef with Apple

I have been thinking about just putting some thoughts down for a while. I’d also like to say I don’t have a favourite vendor or affinity with a manufacturer. I work with Microsoft, Google and other companies stuff all the time. The right tool for the job is my ethos.

Recently I have got a real hump with Apple in general. We have had (in total) in our house:

  • iPod classic
  • 2 x iPod touch
  • iPhone 4
  • iPad 2
  • Unibody MacBook
  • So you can’t say I can’t talk about their stuff as they have certainly taken my money.

    My main problem is how quickly they seem to abandon products and stop releasing upgrades/patches. My old first gen iPod Touch is stuck on iOS 3 something which has known security vulnerabilities and at the time they could of fixed. In the end it helped as I could use the PDF flaw to install Cydia but that’s another story. My iPhone 4 and iPad 2 are more than capable of running Siri but no you need to upgrade. ( Turns out its crap anyway but that’s not the point ). iOS 6 maps are a joke and don’t get me started on there ‘Enterprise’ features such as VPN that I’m currently fighting with.

    Their lock in also annoys me. The only method of playing stuff purchased on iTunes’s is to use a MacBook with iTunes and let that download purchased tunes so you can extract MP3’s from its file system. So iCloud won’t let you access anything of use using a browser. Not even my bloody photos taken with iDevices. Even my MacBook running OSX Lion can’t unless I pay £10 for an iPhoto upgrade. And iTunes is still a spreadsheet smothered in excrement.

    Don’t get me wrong. The industrial design is mostly beautiful and has helped inspire/ kick the industry into making decent products. However they also make some stupid decisions like the new lightning connectors on the new kit. 1000’s of aftermarket devices just going to end up in landfill or lots of £20 adapters being sold……

    I’m astounded that normal folks will pay a lot of their hard earned money to buy their devices. Perhaps they don’t care about some of the things I have said but its very difficult to explain to them that no I can’t get your pictures off easily or no you music can’t be played anywhere else

    Me. Well the iPad and macbook are going soon. The iPhone went a while back so I have nearly purged my life of their stuff. Not good riddance but more ‘go away, get your sh1t together and don’t bother me for a while’

    iPhone-less

    Yay. I’m finally free of my iPhone 4 as of a couple of days ago. They may be fairly decent portable computers but IMHO are second rate phones. Also once you are outside of the standard apps most of the others are pretty crummy

    I’m now the proud owner of a Nokia Lumia 900 running Windows Phone 7. If you want to see something really well thought out with beautiful hardware then check one out. The integration the OS has with Twitter and Facebook is really good and sets a standard iOS really needs to catch up to

    Plus im not an iSheep (well apart from the iPad, Mac and old iPod Touch) but im working on that!