What is the biggest attack in GBPS you stopped

[firewalluser]

@Supermule:

Its in the OS. Hardware can easily handle it if you got some muscle.

I can take this site offline using a specific type of traffic that takes no more than 70-80Mbps bandwith.

When that traffic hits pfSense, its dead. Goes offline instantly. No matter how powerful the hardware is.

I run 8 Core, 16GB ram and SSD. Dead in a second if it hits.

Exploiting the multithreading capabilities perhaps?

[Supermule]

Perhaps :)

[firewalluser]

@ghislain26:

hi,

i am hit by ddos (upd flood mostly) and looking for solutions, hopefully opensource ones. I wanted to know what was the biggest multi gigabits attack you successfully stopped with your pfsense setup in the field ( so not with nullrouting at ISP level) and what the hardware used was.

My actuel issue is on the 5 to 10 gbps DDOS udp flood attacks so i search to see if a 20gbps filtering firewall could work in the real world of April 2015 and help me mitigate 1-16gbps attacks. My problem is to filter myself not ask upstrream to help so i really speak of how i can filter this and if anyone here had setup playing at this level of gbps.

regards,
Ghislain.

Some DDOS attacks can be nullified by simply changing the ip address(es) at the dns level.
Where a DNS lookup is taking place, you need to identify the rogue who is doing the dns lookup and send them off to 23.37.28.215 or 195.99.147.120 if you have a sense of humour which contrary to popular belief also includes these guys 77.87.229.22.  ;D

[firewalluser]

@Supermule:

I can tell you this much….

Windows firewall doesnt get affected by any of these attacks. If you put the server out front and only have WF running and forwarding traffic to the server then it can handle it easily.

It seems to only affect UNIX/Linux/BSD distros.

But MS are no longer supporting ISA server or its later rebranded versions last time I looked, but there might still be a way of exploiting the windows core in similar circumstances.

[Supermule]

Could be. And yes its not supported any more.

But we were testing…..

[firewalluser]

@Supermule:

No….but maybe some updates to what they find or not find??

Maybe hints to what could be done to minimize impact by adding things to system -> tunables??

Have you considered that CMB is now under contract and cant disclose? This was something disclosed by Snowden, some individuals were forced/required to form a legal entity under guidance of the NSA.

http://www.tomsguide.com/us/nsa-tech-coercion,news-17517.html

[Supermule]

HAHAHAHAHAHAHAHA :D

If thats the case, then pfSense is dead as of THIS moment :D

[gadnet]

@firewalluser:

Some DDOS attacks can be nullified by simply changing the ip address(es) at the dns level.
Where a DNS lookup is taking place, you need to identify the rogue who is doing the dns lookup and send them off to 23.37.28.215 or 195.99.147.120 if you have a sense of humour which contrary to popular belief also includes these guys 77.87.229.22.  ;D

the issue is on a webserver with XX+ domains the udp attack do not show which one is targetted and also some domains are handled by the main branch of the customer of our customer's office in another country with days of business paperwork nonsense to finaly react and change the dns :)

this is why i started to look at beeffy machines with pfsense to help but first i try to gather information about people using it for this and it seems no one, that answer here, use pfsense in multi gigabit setup or has experienced multi gigabit attacks on a pfsense box. I am happy thet they do not get attacked but i would have loved they had been to have some feedback ;p Supermule is providing feedback on "small scale" attack that would take down a firewall like this so i am not closer to any solution right now  (and still fight on DC side to get a POC setup) :)

[Supermule]

Lowprofile and I both have 10bgit setups in the production scenario and they are affected the same way.

We dont need to run high bandwith attacks like DNS, NTP, SSDP or anything like that when the interesting stuff takes place when using small bandwith scripts that takes the firewall offline.

When using little bandwith, then the attacker multiplies in numbers since they dont need 1gbit or more to take you offline. They only need a 50mbit pipe to do so.

THATS the scary part!

[firewalluser]

@Supermule:

Could be. And yes its not supported any more.

But we were testing…..

Its possible to make the Windows core hang in some circumstances from the net even desktops behind fw's, but havent tested Win8 or later. Seen it on ubuntu 14.04 as well.

@ghislain26:

@firewalluser:

Some DDOS attacks can be nullified by simply changing the ip address(es) at the dns level.
Where a DNS lookup is taking place, you need to identify the rogue who is doing the dns lookup and send them off to 23.37.28.215 or 195.99.147.120 if you have a sense of humour which contrary to popular belief also includes these guys 77.87.229.22.  ;D

the issue is on a webserver with XX+ domains the udp attack do not show which one is targetted and also some domains are handled by the main branch of the customer of our customer's office in another country with days of business paperwork nonsense to finaly react and change the dns :)

this is why i started to look at beeffy machines with pfsense to help but first i try to gather information about people using it for this and it seems no one, that answer here, use pfsense in multi gigabit setup or has experienced multi gigabit attacks on a pfsense box. I am happy thet they do not get attacked but i would have loved they had been to have some feedback ;p Supermule is providing feedback on "small scale" attack that would take down a firewall like this so i am not closer to any solution right now  (and still fight on DC side to get a POC setup) :)

I wonder if the L2 cache is causing a problem. Can this exploit be tried on a non AMD64 instruction set cpu if such a chip/device exists which can run pfsense and handle the bandwith? Its not something I can test on my RPi's sadly.  ;)

http://www.lshift.net/blog/2013/10/08/cpu-cache-collisions-in-the-context-of-performance/

Edit. A quick search suggests its not possible to switch off the L2 or any other cache now adays in the bios, but one way around this might be to limit it to a single core instead which will be doable on VM's like ESXI.

When I suggest a non AMD64 cpu, please include the x86 32bit cpu's as well.

I sadly can not participate in this little experiment due to only having 5MB download, but would be interested to see the data generated by the scripts none the less, so Supermule if you dont mind sharing the script via pm, I'd be curious to see what it generates to see what patterns are observed over a closed network between a couple of machines.

FWIW.

[Supermule]

I run this in the test bench

http://ark.intel.com/products/33927/Intel-Xeon-Processor-E5420-12M-Cache-2_50-GHz-1333-MHz-FSB

12M L2 cache. I actually dont know how big the L1 cache is.

[Supermule]

This is what I run in the datacenters pfsense clusters

http://ark.intel.com/products/47920/Intel-Xeon-Processor-X5670-12M-Cache-2_93-GHz-6_40-GTs-Intel-QPI

[kroberts]

Full disclosure:  I'm a hobbyist here, no multi-gigabit access.

You said this works on Linux too.  Is there common networking code between the two?

I would surely like to see a patch before this goes public, but IMO full disclosure to official channels might be a good option.  For example, https://www.freebsd.org/security/reporting.html if it's freebsd itself, or https://www.kb.cert.org/vuls/html/report-a-vulnerability/ if it's cross-platform.  Both offer encryption keys to send confidential information.

[Harvy66]

Anyone know what "kernel" is? When I was getting DDOS'd by SuperMule, that process seemed to be the offender. Prior to his attack, I have never seen that process. Just based off of this, kernel seems to be doing a lot of work that it probably doesn't need to be doing or is doing in a slow way.

[KOM]

Probably a NIC driver hook into the kernel or something like that.  This may be helpful if anyone hasn't already seen it:

https://forums.freebsd.org/threads/high-cpu-interrupts-on-the-router-igb-driver-how-to-fix.28219/

[Supermule]

First one is idle…Second one is during DoS

[Harvy66]

@KOM:

Probably a NIC driver hook into the kernel or something like that.  This may be helpful if anyone hasn't already seen it:

https://forums.freebsd.org/threads/high-cpu-interrupts-on-the-router-igb-driver-how-to-fix.28219/

The funny thing is my interrupts were low, it was "kernel" that was high. On average, my NIC interrupts consume about 130x more CPU than kernel, but during the DDOS, kernel was suddenly doing a lot of stuff. Even when load testing PFSense via WAN-LAN+NAT, I never see kernel. Normally interrupts are the number one cause of load on the firewall, which makes sense because it's just a ton of network IO.

I wonder what kernel is doing that it suddenly decides to do 10,000x more work than it normally does.

Poorly scaling algorithm?

[firewalluser]

@KOM:

Probably a NIC driver hook into the kernel or something like that.  This may be helpful if anyone hasn't already seen it:

https://forums.freebsd.org/threads/high-cpu-interrupts-on-the-router-igb-driver-how-to-fix.28219/

Possibly, but that doesnt explain how windows core & linux hangs when sat behind firewalls like pfsense which processes each packet before sending it inwards to the lan. Put another way it would seem pfsense can hang windows and linux machines sat behind them.

[cmb]

@Supermule:

Lowprofile is also in this test scenario.

And he ended up with a config that stands up to said attacks. Edit: though further testing saw other problems.

I have packet captures of the traffic that's generated by the tools from when lowprofile ran it against one of our systems. It's nothing special that I saw, and we went through multiple types. If someone would like to provide additional pcaps, I'll definitely check them out.

@firewalluser:

Have you considered that CMB is now under contract and cant disclose? This was something disclosed by Snowden, some individuals were forced/required to form a legal entity under guidance of the NSA.

And now we're into conspiracy theories. No, that's not the case.

@Harvy66:

The funny thing is my interrupts were low, it was "kernel" that was high.

It's the queues of the NIC, not just kernel. That's where a good chunk of pf's processing will show. Where you're hitting the packet filter hard, that's what you will see.

@Supermule:

First one is idle…Second one is during DoS

You have polling enabled, which probably isn't a good idea (in theory it might help such circumstances, in practice especially in a VM it's probably not good). You're also running snort, and logging blocked DDoS traffic from the looks of it. All not good for DoS resiliency.

@firewalluser:

Put another way it would seem pfsense can hang windows and linux machines sat behind them.

You're passing enough attack traffic through to hang Windows and Linux in that case.

[lowprofile]

My last test with 2.2.2 was a big failure. Right now i am struggling to get pfsense stable (2.2.2)
But i did a test and it was not impressive. A standard configuration. After adjusting it was still not good enough at all. So now i will go trough all tweak and tuning again in 2.2.2…. re-google and start all over. the syn proxy feature should easily had solved this issue, but i will make further test and return. I tried with a general SYN proxy rule. I locked my self out from gui... no response, then tried again since it was replying ICMP request, but no difference. The SYN proxy feature should had handled this issue, but it is not working as it should. Same behaviour.

Read this as well as i think some settings here would help. http://people.freebsd.org/~jlemon/papers/syncache.pdf
I will return after some test.

It would be nice if you could set a treshold for SYN proxy in general. e.x 100 half open connection pr. ip would trigger SYNproxy to be enabled....