When we wrote our initial blogpost regarding the evasion of Cisco ACLs by (Ab)Using IPv6, where we described (known to Cisco) cases of Access Control Lists (ACL) circumvention, we also suggested some mitigation techniques including the blocking of some (if not all) IPv6 Extension Headers.
Almost a month later, we got a comment from Matej Gregr that, even if the ACLs of certain Cisco Switches are configured to block IPv6 Extension headers like Hop-by-Hop or Destination Options headers, this does not actually happen/work as expected. Of course this made us re-visit the lab in the interim ;-).
Cisco
Evasion of Cisco ACLs by (Ab)Using IPv6 & Discussion of Mitigation Techniques
This is a guest post of Antonios Atlasis.
During our blogpost regarding DHCPv6 Guard evasion, one of the side-effects was that Access Control Lists (ACLs) configured to block access to UDP ports 546 can be evaded by abusing (again) IPv6 Extension headers. Having that in mind, we decided to check the effectiveness of Cisco IPv6 ACLs under various scenarios. Our goal was to examine whether the IPv6 ACLs of Cisco routers can be evaded, as well as under which conditions this can take place. To this end, several representative scenarios from enterprise environments or other potential ones are examined.
Continue readingObservations from the Cisco Live Europe Wifi Infrastructure
Given that Enno and I are network geeks, and that I am responsible for setting up the Troopers Wifi network I was curious which components might be used at Cisco Live and which IPv6 related configuration was done for the Wifi network to ensure a reliable network and reduce the chatty nature of IPv6. Andrew Yourtchenko (@ayourtch) already did an amazing job last year at Cisco Live Europe explaining in detail (at the time session BRKEWN-2666) the intricacies of IPv6 in Wifi networks, and how to optimize IPv6 for these networks. He was also a great inspiration for me when setting up the Troopers Wifi network a couple of weeks later. Thank You!
Continue readingCisco Cloud Services Router 1000V and the Virtual Matryoshka
Recently we started playing around with Cisco’s virtual router, the CSR 1000V, while doing some protocol analysis. We found Cisco offering an BIN file for download (alternatively there is an ISO file which contains a GRUB boot loader and the BIN file, or an OVA file which contains a virtual machine description and the ISO file) and file(1) identifies it as DOS executable:
$ file csr1000v-universalk9.03.12.00.S.154-2.S-std.SPA.bin
csr1000v-universalk9.03.12.00.S.154-2.S-std.SPA.bin: DOS executable (COM)We didn’t manage to get the file running, neither in a (Free-)DOS environment, nor in a wine virtual DOS environment, except using the boot loader from the ISO file. So we became curious as for the structure and ingredients of the file.
Continue readingFresh Meat From the Coding Front
Within the last months I had some time to work on my code and today I’m releasing some of that: a new version of dizzy as well as two new loki modules.
New version of dizzy:
Download version 0.8.2 here.
USB target support
Dizzy is able to use neighbor travis’ facedancer to emulate a client device. Two fuzzing modes are available for USB descriptor fuzzing and USB endpoint fuzzing.
Here is an example cmd to start usb configuration descriptor fuzzing:
Continue readingConfiguring IPv6 Snooping and DHCPv6 Guard on Cisco IOS
Hi everyone,
Some of you may already know (the ones who are following Enno on Twitter) that Enno and I had our lab day in preparation for the IPv6 Security Summit at Troopers. We had a brand new and shiny Cat4948E as our lab device to do some testing of the current generation of Cisco’s IPv6 First Hop Security (FHS) mechanisms. The Catalyst was running the latest image available (15.1(2)SG3).
In this small blog post, we will take a look at the configuration and behavior of IPv6 Snooping and DHCPv6 Guard. So let’s start with IPv6 Snooping:
Continue readingA Word on Cisco Jabber
Recently we took a look on Ciscos XMPP client, called Cisco Jabber. The Client is used in combination with Ciscos Unified Communication Server (CUCM) and Ciscos Unified Presence Server (CUPS). Only the latter one is used for XMPP communication.
We built a small lab setup with this components (CUCM, CUPS and the Win7 Client) and watched the client working.
First the client connects to a web service at https://CUPS:8443/EPASSoap/service/v80. We intercepted this connection with the Burp Proxy and had no problems getting into the SSL. Inside we found a SOAP request containing the users authentication credentials and a SOAP response with a onetime password, which is used for authentication in the XMPP stream later on. Phew, the users credentials _and_ unlimited onetime passwords _that_ easy? Thanks Cisco!
Continue readingAll Your Calls Are Still Belong to Us – continued
Hi again and a happy new year 2013!
Lets continue were I left you the last time.
The CTL
The CTL is basically a binary TLV file with 1 byte type, followed by 2 bytes length and finally the data. But as this is far to easy, some special fields omit the length field and just place the data after the type (I guess those are fields with a fixed length). Here is an example CTL file:
Continue readingAll Your Calls Are Still Belong to Us – aka. Hacking Cisco high secure Enterprise VoIP Solution
Some of you may have heard the topic before, as we have spoken about on this years BlackHat Europe, TROOPERS12 and HES12, so this is nothing completely new, but as we’re done with responsible disclosure (finally (-; ) and all the stuff should be fixed, we’re going to publish the code that brought us there. I will split the topic into two blog posts, this one will wrap up the setup, used components and protocols, the next one [tbd. till EOY, hopefully] will get into detail on the tools and techniques we used to break the enterprise grade security.
Continue readingGroundhog Day: Don’t Pay Money for Some Else’s Calls, Still
Hi everyone,
it’s me again with another story of a toll fraud incident at one of our customers (not the same as the last time of course ;-)).
The story began basically like the last one: We received a call with an urgent request to help investigating a toll fraud issue. Like the last time I visited the site in order to get an idea on what was going on exactly. The customer has a VoIP deployment consisting of the whole UC Suite Cisco offers: Call Manager, Unity Connection for the voice mailboxes, Cisco based Voice-Gateways and of course, IP phones.