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Category: Security (Page 2 of 2)

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 !

RSA Authentication Manager–Custom Reports

Working with this product, its evident that the inbuilt reports are not that useful for certain things.   I wanted to find a way of logging users who have used SecurID to authenticate against a number of hosts.

So time to learn the custom queries section of the product, me thinks.

The Server is (obviously) SQL based.  The schema is fairly easy to understand, especially if you look at the examples within the help text or provided on the server.

It is possible to import my SQL scripts by creating a new Custom Query then pasting in the SQL. So…. scripts:

Todays Unique User Count

SELECT COUNT(DISTINCT chUserName) 
FROM SDLogEntry 
WHERE dtLocalDate = GMTDateNow   
AND iMessageNum = 1011   
AND (CHClientName = "host1" OR CHClientName = "host2")

Remember to change the host1 and host2 entries to your device host names obviously.  If you have more then add more to the last AND

Message Number 1011 is a ‘Passcode Successful’ – meaning a successful authentication

Todays Successful Users

SELECT SDLogEntry.dtLocalDate, SDLogEntry.TLocalTOD, SDLogEntry.chUserName, SDLogEntry.chLogin, SDLogEntry.chClientName, SDLogMessage.chShortMessage
FROM SDLogEntry, SDLogMessage 
WHERE SDLogEntry.dtLocalDate = GMTDateNow   
AND SDLogEntry.iMessageNum = 1011   
AND SDLogMessage.iMessageNum = SDLogEntry.iMessageNum  
AND (SDLogEntry.CHClientName = "host1" OR SDLogEntry.CHClientName = "host2")

Again 1011 is a successful passcode.

This uses a select from multiple tables to get the actual description of the message number to make the report more readable.

Todays Failures

SELECT SDLogEntry.dtLocalDate, SDLogEntry.TLocalTOD, SDLogEntry.chUserName, SDLogEntry.chLogin, SDLogEntry.chClientName, SDLogMessage.chShortMessage
FROM SDLogEntry, SDLogMessage 
WHERE SDLogEntry.dtLocalDate = GMTDateNow   
AND SDLogEntry.iMessageNum <> 1011   
AND SDLogMessage.iMessageNum = SDLogEntry.iMessageNum  
AND (SDLogEntry.CHClientName = "host1" OR SDLogEntry.CHClientName = "host2")

This uses the same format as success but with a ‘not’ 1011.  The report can be useful to troubleshoot users having problems or who are dim 🙂

Using Arguments to Select Dates

All of the above are for a single day, which is which is specified by the ‘GMTDateNow’ value.  This can be changed to use Argument Selectors which you can build in the same screen as the SQL entry.  Thus an example of ‘Successful Users’ would be:

SELECT SDLogEntry.dtLocalDate, SDLogEntry.TLocalTOD, SDLogEntry.chUserName, SDLogEntry.chLogin, SDLogEntry.chClientName, SDLogMessage.chShortMessage
FROM SDLogEntry, SDLogMessage 
WHERE SDLogEntry.dtLocalDate > ARG01 AND SDLogEntry.dtLocalDate < ARG02
AND SDLogEntry.iMessageNum = 1011   
AND SDLogMessage.iMessageNum = SDLogEntry.iMessageNum  
AND (SDLogEntry.CHClientName = "host1" OR SDLogEntry.CHClientName = "host2")

Where ARG01 = Start Date and ARG02 = End Date

These can be applied to any of the reports.

Other Information

One thing I found is that the custom queries are stored locally on the machine that create the reports so to share them to others you have to use a fileshare, USB disk or similar method.

Also the HTML format reports aren’t to bad so its worth a look at using this output method.

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