Breaking

Autonomic Network Part 3: Vulnerabilities

This is the 3rd post in the series of Autonomic Network (AN), it will dedicated for discussing the vulnerabilities. I recommend reading the first 2 parts (part one, part two) to be familiar with the technology and how the proprietary protocol is constructed.

Initially we will discuss 2 of the reported CVEs, but later there is more CVEs to come 😉

Continue reading “Autonomic Network Part 3: Vulnerabilities”

Continue reading
Breaking

Autonomic Networking – Part 2: Analysis

This is the second part in the Autonomic Network series. We have introduced previously in our first part the Autonomic Network (AN), took a look about the needed configuration to run it on Cisco gear and what is the expected communication flow. In this post, we will dive deeper to have a closer look on the packets and how they are composed. Continue reading “Autonomic Networking – Part 2: Analysis”

Continue reading
Breaking

Autonomic Networking – Part 1: Overview

This is a 3-part series which introduces and analyzes Cisco’s implementation for Autonomic Network. In the 1st part, the technology is introduced and we have an overview about communication flow. In the 2nd part, Cisco’s proprietary protocol is reverse engineered 😉 then finally in the 3rd part, multiple vulnerabilities will be disclosed for the first time. If you’re aware of the technology, you can skip directly to part 2 where the action begins!  Continue reading “Autonomic Networking – Part 1: Overview”

Continue reading
Breaking

CVE-2016-1409 – IPv6 NDP DoS Vulnerability in Cisco Software

Dear readers,

As you may have already noticed, Cisco released an urgent security advisory describing an IPv6 Neighbor Discovery DoS Vulnerability in several flavors of Cisco’s operating systems. Currently IOS-XR, XE and NX-OS are affected while ASA and “classic” IOS are under investigation. At first glance, it might look like yet another IPv6 DoS vulnerability. Looking closer, Cisco is mentioning an unauthenticated, remote attacker due to insufficient processing logic for crafted IPv6 NDP packets that are sent to an affected device. Following the public discussion about the vulnerability, it seems that these packets will reach the, probably low rate-limited, LPTS filter/queue on IOS XR devices “crowding” out legitimate NDP packets resulting in a DoS for IPv6 traffic, or in general a high CPU load as these packets will be processed by the CPU. More details are currently not available, but this might indicate the affected systems aren’t doing proper message validation checks on NDP packets (in addition to the LPTS filter/queue problem).

Continue reading “CVE-2016-1409 – IPv6 NDP DoS Vulnerability in Cisco Software”

Continue reading
Events

Observations from the Cisco Live Europe 2016 Wifi Infrastructure

Good Evening,

Enno and I spent the first day on Cisco Live Europe in Berlin today attending the “Advanced Practical Knowledge for Enterprise Deploying IPv6” technical breakout held by Tim Martin and Jim Bailey. It was a good breakout session, and thanks again Tim for the honorable mention of our work in your slides! We really appreciate it. Like last year, we were curious how the Wifi network was setup this year as I face a corresponding task for Troopers in March, with some major changes in comparison to the last years. Continue reading “Observations from the Cisco Live Europe 2016 Wifi Infrastructure”

Continue reading
Events

#TR16 IPv6 Security Summit Teaser: Building a Reliable and Secure IPv6 WiFi Network

Hi everyone,

some of you may have seen my last blog post about the preparation of the Troopers network. Today I want to give you a little teaser on what to expect for the talk I will present during the IPv6 Security Summit. As the title implies, it’s not only about building a secure IPv6 WiFi, but also a reliable one. One might think that there aren’t many differences in comparison to IPv4, but the heavy reliance on multicast of IPv6 does have implications for Wi-Fi networks in general. Continue reading “#TR16 IPv6 Security Summit Teaser: Building a Reliable and Secure IPv6 WiFi Network”

Continue reading
Events

DHCPv6 Option 52 on Cisco DHCPv6 Server

Hi,

I am currently preparing the Troopers network in a lab environment to ensure that we all will have a smooth Wi-Fi experience during Troopers. I wanted to spice things up a little bit for the Wi-Fi deployment (more on that in a following blogpost) and get rid of IPv4 wherever possible. Our Wi-Fi infrastructure consists of typical Cisco Access Points (1602) and a 2504 Wireless LAN Controller. Beginning with WLC image 8.0 it is finally supported to establish the CAPWAP tunnel between the AP and the WLC over IPv6, which is awesome and I wanted to implement it right away. Continue reading “DHCPv6 Option 52 on Cisco DHCPv6 Server”

Continue reading
Breaking

Cisco and the Maintenance Operation Protocol (MOP)

Howdy,

this is a short write up about the Maintenance Operation Protocol (MOP), an ancient remote management protocol from the DECnet protocol suite. It’s old, rarely used and in most cases not needed at all. But as we stumbled across this protocol in some network assessments, it seems like a lot of network admins and other users don’t know about it. Even various hardening guides we’ve seen don’t mention MOP at all.

Continue reading “Cisco and the Maintenance Operation Protocol (MOP)”

Continue reading
Breaking

Evasion of Cisco ACLs by (Ab)Using IPv6 – Part 2

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 ;-).

Continue reading “Evasion of Cisco ACLs by (Ab)Using IPv6 – Part 2”

Continue reading