I was asked a few weeks ago by our field engineers to provide a fix for the OSPF vulnerability exposed by Black Hat last month. Prima facie there appeared nothing new in this attack as everyone knows that OSPF (or ISIS) networks can be brought down by insider attacks. This isnt the first time that OSPF vulnerability has been announced at Black Hat. Way back in 2011 Gabi Nakibly, the researcher at Israel’s Electronic Warfare Research and Simulation Center, had demonstrated how OSPF could be brought down using insider attacks. Folks were not impressed, as anybody who had access to one of the routers could launch attacks on the routing infrastructure. So it was with certain skepticism that i started looking at yet another OSPF vulnerability exposed by Gabi, again at Black Hat. Its only when i started delving deep into the attack vector that the real scale of the attack dawned on me. This attack evades OSPF’s natural fight back mechanism against malacious LSAs which makes it a bit more insidious than the other attacks reported so far.
I exchanged a few emails with Gabi when i heard about his latest exposé. I wanted to understand how this attack Continue reading
This post is about finding and fixing a memory leak I discovered in the SNMP daemon, snmpd(8), in OpenBSD. This sort of analysis is foreign territory for me; I’m not a software hacker by day. However, using instructions written by Otto Moerbeek as my Rosetta stone and Google to fill in the blanks when it came to usage of the GNU debugger, gdb(1), I was able to find and fix the memory leak.
I’m documenting the steps I used for my future self and for others.
When walking the pfTblAddrTable in the OPENBSD-PF-MIB, the unprivileged snmpd process would grow in terms of SIZE and RES. Querying other parts of PF-MIB or other MIBS altogether resulted in no memory usage increase.
Since I knew roughly which code path must have the leak, I first examined it manually. I could not see where memory wasn’t being given back. I needed to instrument the process as it was running in order to find the leak.
This set of instructions from Otto Moerbeek was my guide. As per his guide, you have to rebuild libc with MALLOC_STATS enabled. This enables statistics collection that is used later on.
Edit /usr/src/lib/libc/stdlib/malloc. Continue reading
This post is about finding and fixing a memory leak I discovered in the SNMP daemon, snmpd(8), in OpenBSD. This sort of analysis is foreign territory for me; I'm not a software hacker by day. However, using instructions written by Otto Moerbeek as my Rosetta stone and Google to fill in the blanks when it came to usage of the GNU debugger, gdb(1), I was able to find and fix the memory leak.
I'm documenting the steps I used for my future self and for others.
Lately I’ve been bouncing some generic DMVPN questions off the twittersphere. I’ve used DMVPN sporadically in tiny single-use cases before, but now I am planning to roll out a somewhat larger implementation with a dual cloud and dual hub, complicated by the fact that I don’t control the perimeter router at our DC and I […]
The post Professional Loneliness appeared first on Packet Pushers Podcast and was written by Matthew Mengel.
Why’s everyone complaining about overlays; it’s the underlays that are the problem. I’ve been in this awful game for years, I’m tellin ya, me and the dinosaurs were buddies back in the medieval donkey days – so listen up losers, I’m diatribin from experience. That Greg Ferrous, he’s a wise fella; almost like a father to me […]
The post Don’t Need No Stinking Underlays appeared first on Packet Pushers Podcast and was written by Steven Iveson.
A basic network is setup and OSPF is configured. R1 is then prevented from forming an OSPF adjacency with R2 due to R1’s serial interface being configured as a passive interface.
Only Hello packets are seen from R2.
From this Wireshark output we can see:
Well I just got my itinerary for my trip to Sunnyvale for the Juniper Ambassador’s Summit in October and my wife and I have decided to spend an extra couple of days either side to get out and see the sites. We will be arriving in San Francisco at 11am Sat 5th of October and flying out around 11pm on Friday 12th, and we are looking to fill our schedule!
This is my wife’s first trip to the US, and I know she wants to get out and about and see things (also probably while Im in conference too). I know her list includes seeing the Golden Gate Bridge and Alcatraz… oh… and… “The Full House House”.
Thankfully we have the company of two of my good friends who are locals – Ashton (from Juniper) and my old work mate Cooper Lees, and we are working out “what we should see”.
So what do you consider “must see” things in this area? Let me know in the comments and we will see what we can fit in.
Also, while we’re in town, I would love to catch up with any locals in the area for drinks/coffee/food etc so Continue reading
Managers everywhere are abusing their employees by using priorities to convey to-do lists. It is not because of anything insidious in their objectives, but the average manager (both low- and high-level, by the way) simply doesn’t think enough about priorities to really do anything meaningful with them. For teams I lead, our entire existence revolves […]
The post The Priorities Bill of Rights – 10 practical steps to managing group priorities appeared first on Packet Pushers Podcast and was written by Michael Bushong.