What is the biggest attack in GBPS you stopped

tim.mcmanus

I thought DTrace was getting nowhere because it requires ESF to include it in the version of freebsd they use with pfsense?

Let me back up a bit and summarize some of the results I got while testing. Initially the box and web UI slowed to a crawl while the attack was going on. When I increased my state table to 8M states, the box responded well, but I started getting an IRQ storm alert. That led me to believe that there was an issue in the em network driver in FreeBSD. In order to validate this assumption, I would need to install FreeBSD on bare metal and re-run the tests. Troubleshooting 101, remove stuff, check for error, profit. If it can be recreated in FreeBSD 10.x, then we can install dtrace there and go forward. No use trying to troubleshoot a potential FreeBSD issue on a pfSense box. Even the folks on the FreeBSD forums will tell you to do a vanilla install on bare metal and then post the results. I believe that it's possible that someone did run a test with FreeBSD and reported the same behavior on this thread. I'm not entirely sure. But that's essentially where the troubleshooting left off.

@firewalluser:

I think he provided a DDOS script which was supposed to cause the problems although I havent seen it myself as my bandwidth is not enough unless GCHQ/isp have some speed restriction in place, but I cant comment on the DDOS script other than its not unlike many which can be downloaded from the web.

Just to be clear, the attack was a DOS, not a DDOS. There was nothing distributed about it unless Supermule has a botnet at his disposal and that's why he's not releasing any code (I doubt it), but I think it's a single script randomizing source IP addresses. It could be that he's downloaded someone else's compiled code and is just using it like a script kiddie, and therefore he doesn't have any source code to release. That might be more probable, but we'll never really know until he provides some transparency.

I stopped working on the issue because I don't have the source to recreate the issue, and therefore I cannot test it in a lab. I provided my external IPs to Supermule, but I never got the same transparency in return. So I walked away.

At first I really don´t think thats a easy going job, only coding something new, insert it in the
next FreeBSD version and then pfSense will be the profiteer also in the next version, because
pfSense is not swapping over the code 1:1 without doing many adaptations and changes as
well.

And what would be the benefit from this all, if some dozen peoples like anonymous, were
shooting with their "super canon"? Would this also secure our pfSense firewalls? Either
on bare metal or in a VM this would be the end of any firewall that is trying to proper
handle a load like this then.

Would it perhaps be better to own something like a so called "hedgehog mode"
like the bigger vendors are doing on greater devices?

For sure the attack driven by @supermule was a mixed one, a script combined with
a special syn flood attack. (XSYN script and OVH )

@firewalluser

I think he provided a DDOS script which was supposed to cause the problems although I havent seen it myself as my bandwidth is not enough unless GCHQ/isp have some speed restriction in place, but I cant comment on the DDOS script other than its not unlike many which can be downloaded from the web.

You can easily watch it here: This is the XSYN script

firewalluser

I think theres too much focus on the (d)dos and not enough on the fact, that, observing a system in general at a greater level of detail can show up new anomalies.

Put another way, until we log at greater detail how will we spot problems?

Dtrace wouldnt exist if there wasnt a need for it, would it?

I know OS Debugging can add an overhead, but having used tools like this one http://www.rohitab.com/apimonitor on the Windows platform has enabled me to spot things which otherwise would have gone unnoticed by using the programming languages own debugger because I could see which API's get repeatedly and unnecessarily called in OOP code for example.

That api monitor hooks into all the api's I choose and from that I can get metrics which show me things like where my code is slow, and where there might be potential problems which can be exploited at the OS level. I've found bugs in programming languages which are over 15years old possibly 20yrs and could cause any system written in the language to crash.

The thing to bear in mind with all good systems is they tend to have the original programmer(s) still in place, unlike many of the OS's today which have been taken over by younger folk as others climb the management ladder or go off elsewhere.

Those newer folk dont have the hidden knowledge thats in the heads of the original programmers. So if you dont have greater levels of logging and detail, would we spot what we maybe currently missing?

Syslog is a good, but like money you can never have enough.

would we spot what we maybe currently missing?

Hmmm, I will try it to explain it could be a very simple thing!

As I was digging out from some forum threads here and there it
would be not affecting lazy consumer routers, the combined attack
I mean and there for I think there must be an elemental difference
between the NAT from FreeBSD and the NAT in consumer routers.

The NAT at consumer routers do the following think;
They will not pass anything in from outside that was not called
by somebody or a device from the LAN side! Is this right so? ;)

The NAT at FreeBSD or pfSense based devices do also the following
likes above but on another way! And I mean really this is the small
piece that makes it really difficult to fix the entire problem. :-
FreeBSD & pfSense lets the packets in or pass to inspect
them that the rules can matching them for deny or allow or perhaps
pass through.

That means that at the lazy consumer routers the packets don´t comes
in but at the pfSense side they must be coming in at first to match
the rules. Can this be the small piece of difference here in the game?

Asch Conformity, mainly the blind leading the blind.

But the one-eyed man is the king of the blinds

Supermule

Its not like that.

firewalluser

@BlueKobold:

The NAT at consumer routers do the following think;
They will not pass anything in from outside that was not called
by somebody or a device from the LAN side! Is this right so? ;)

The NAT at FreeBSD or pfSense based devices do also the following
likes above but on another way! And I mean really this is the small
piece that makes it really difficult to fix the entire problem.

Good thinking, could not say if its correct or not as I have no knowledge of how the different consumer routers work, they might for example have different levels of isolation or sandboxing in place. However from the freebsd thread SYN ACK seems to be an issue.

I dont know if this would work, by altering the number of retries?
https://forum.ivorde.com/quick-temporary-tuning-of-freebsd-under-spoofed-syn-flood-attack-t13632.html

As I cant replicate this at my end I am unable to reproduce which is half the problem but not impossible when trying to fix bugs of sorts, hence the suggestion to increase the logging at the system level. Maybe something would show up?

Good thinking, could not say if its correct or not as I have no knowledge of how the different consumer
routers work, they might for example have different levels of isolation or sandboxing in place.

In normal as I am informed, correct me please if I am wrong with this, the NAT mechanism is working
like this (related to the consumer grade NAT routers), the way ste-by-step I mean;

rule number one is often using netfilter (SPI) in that game to prevent from IP packet fragmentations
the second rule is something like "use rule number one on top of all other rules then followed by NAT
from the LAN side someone or a device is calling an information such like a website to open and display
the informations are send to the Internet by opening a session for this related to an internal IP address
if data now from the outside (Internet) are reaching the WAN interface of the home router, the NAT
mechanism is purely and only checking if there is an open session that is matching this data and let
them pass or deny them.

And for sure on top of this, perhaps also a smaller soldered on board ASIC/FPGA that brings them
up to handle those rules and actions more liquid I am really pretty sure they own all something like this.

I now I am walking now on so called thin ice
For sure from vendor to vendor this might be used in different ways, but it is really affective
working for them, so could pfSense or FreeBSD also going to solve this out like this is done?

And if the most peoples want to go more likes the style is now, no problem at all I thing, it might
be not working only as a replacement, an extension or only as another option for the state of
art, the pfSense is acting and handling this point now at the time, but perhaps something like
a second option where each user will be able to set it up or activate it or may not perhaps.

However from the freebsd thread SYN ACK seems to be an issue.

But you are perhaps a programmer or code writer that is able to determinate now
where are the exactly differences between this both SPI/NAT versions?

Put another way, until we log at greater detail how will we spot problems?

You will be able to sniff, syslog and debug for many years something and millions of clean
code audits on top, if the mechanism it selfs (SPI/NAT) is the point we have to come closer

I dont know if this would work, by altering the number of retries?

Hey, can this combined together by using syncookies against syn flood attacks?

I am not a code writer or FreeBSD and pfSense professional and also not a security
expert likes many users are here in this forum are, and this may be bringing me up
to ask some poor questions that makes more or long time experienced users and the
pros up to be running wild, but if there is out something else "they" have and not "we"
and it is still working likes a charm you will perhaps excuse the jumping in to this discussion.

Supermule

https://technet.microsoft.com/en-us/library/cc756722%28v=ws.10%29.aspx

I think the issue is how NAT is handled and whats done to the traffic in the queue. I dont know how deep this goes but it could be different things.

I dont have any waiting hardware wise and its internal to FreeBSD/pfSense.

It could be the backlog and the way its handled when SYN flooded and also the fact that all traffic is copied to pf filter and inspected and then its forwarded/rejected or whatever its supposed to do…

That we have a bottleneck in that way the packets are handled using NAT. The script used spoofed IP's and is a DDoS. The traffic will at a point be flushed and then the firewall begins to route traffic again until we hit the bottlenneck again and everything halts and become unresponsive.

1 core suddenly uses 100% of the CPU and it stalls depite having enough ressources available.

So its tied to PPS and how they are composed and what the traffic wants in regards to reply from the FW. And not the overall bandwith usage.

One can monitor the usage of CPU in VmWare and see what happens hardware wise when the traffic drops on the traffic graphs. It follow suit in VmWare and everything is reachable from WAN again.

vmxnet3_vmwareload.png_thumb
traffic_drop.PNG_thumb

traffic_drop2.PNG_thumb

firewalluser

@BlueKobold:

You will be able to sniff, syslog and debug for many years something and millions of clean
code audits on top, if the mechanism it selfs (SPI/NAT) is the point we have to come closer

pfsense has packet capture but its limited ie it falls over after a period of time.

Syslog is not detailed enough in places.

firewalluser

@SM, Have you tried a DMZ with two firewalls?

That way you can offload some work from the front facing fw, and other stuff can run on the rear facing fw?

I know most OS'es as in servers and desktop's have a fw of sorts, but in my experience they are really quite basic not worth relying on which is why my preferred setup is to have two fw's in place with different OS's running as monocultures are never good.

https://technet.microsoft.com/en-us/library/cc756722%28v=ws.10%29.aspx

I think the issue is how NAT is handled and whats done to the traffic in the queue. I dont know how deep this goes but it could be different things.

I mean the differences between this different translation methods as described here;
Methods of translation

is to have two fw's in place with different OS's running as monocultures are never good.

This is owed to the circumstance, if over one system a bug or issue came out it would not be affecting both
Firewalls.

cmb

@KOM:

So we can't expect the pfSense team to fix a problem that's not in pfSense, and they are at the mercy of the FreeBSD code releases.

While we can't expect them to, they certainly have fixed some FreeBSD bugs and submitted the patches upstream, which were accepted for inclusion by the FreeBSD team.

Yup. And if there were truly a world-is-ending issue here, we'd already have done the same already.

All firewalls require some degree of tuning to stand up to resource exhaustion attacks. Settings appropriate for such circumstances aren't defaults because they would break many more circumstances than they would help, as they're too aggressive for many VoIP configurations, among other possible problems. Also general default behaviors that most people want, like logging all blocked traffic, are really terrible in that circumstance. Among a variety of other problems I've pointed out with the scenarios in these threads.

I've seen enough of Supermule's super-secret DDoS stuff from when he (or someone using something similar) DDoSed this forum several times, and some things I've gathered from others, to be able to put together a proper analysis to get upstream at some point.

It's all doable with hping or other tools. Supermule uses shady illegal services you pay for in Bitcoin that use criminal-run botnets. The same circumstance can be lab replicated without paying criminals.

Investigating this further is still on my radar. There have just been real problems that affect many reasonable real world use cases that have taken precedence. Anyone trying to stop DDoS with a firewall of any type is doing it wrong.

cmb

@firewalluser:

I thought DTrace was getting nowhere because it requires ESF to include it in the version of freebsd they use with pfsense?

You need more than just dtrace, various other debug options like PMC, and it needs to be replicated on stock FreeBSD with as basic of a test case as possible. We're not holding anything up there if someone wants to do it right. Doing it right doesn't involve "watch my Youtube videos of what happens when I have a criminal botnet hit me with traffic I won't describe, using an undocumented configuration that's full of sub-optimal settings for standing up to resource exhaustion attacks."

Doing it right would entail:
take this pf.conf
run this against it
end result is: …

So it's clear what's being done, the end result, and how to replicate. There's no big secret in how to run a large scale SYN flood where the world would end if it was put out there.

cmb

@tim.mcmanus:

There was nothing distributed about it unless Supermule has a botnet at his disposal and that's why he's not releasing any code

He's admitted to using a criminal-run botnet, which apparently isn't as strong as it used to be as machines have gotten cleaned.

dennypage

I missed this along the line. But it does explain why he has been unable or unwilling to offer details about the attack method.

@cmb:

He's admitted to using a criminal-run botnet, which apparently isn't as strong as it used to be as machines have gotten cleaned.

Supermule

So you are not sure??

Just because I pissed you off…

I thought you were older than the "name calling" age.

Tell me what I used... And since you have offered little to no help at all in configuring these "sub optimal" configurations, its very clear to everybody that nothing good comes from ESF other than bickering and "sub optimal" communication.

If I really DDoS'ed you then you wouldnt be online yet.

@cmb:

@KOM:

So we can't expect the pfSense team to fix a problem that's not in pfSense, and they are at the mercy of the FreeBSD code releases.

While we can't expect them to, they certainly have fixed some FreeBSD bugs and submitted the patches upstream, which were accepted for inclusion by the FreeBSD team.

Yup. And if there were truly a world-is-ending issue here, we'd already have done the same already.

All firewalls require some degree of tuning to stand up to resource exhaustion attacks. Settings appropriate for such circumstances aren't defaults because they would break many more circumstances than they would help, as they're too aggressive for many VoIP configurations, among other possible problems. Also general default behaviors that most people want, like logging all blocked traffic, are really terrible in that circumstance. Among a variety of other problems I've pointed out with the scenarios in these threads.

I've seen enough of Supermule's super-secret DDoS stuff from when he DDoSed our forum several times (not going to believe it wasn't him), and some things I've gathered from others, to be able to put together a proper analysis to get upstream at some point.

It's all doable with hping or other tools. Supermule uses shady illegal services you pay for in Bitcoin that use criminal-run botnets. The same circumstance can be lab replicated without paying criminals.

Investigating this further is still on my radar. There have just been real problems that affect many reasonable real world use cases that have taken precedence. Anyone trying to stop DDoS with a firewall of any type is doing it wrong.

cmb

I have offered numerous suggestions throughout your threads. If you want in-depth help with your configuration, purchase support, and we'll be glad to assist. Ultimately there's only so much you can do, because firewalls are the wrong answer to DDoS, but it's not horrible in any reasonable circumstance. If you'd even just provide a useful problem report, I would pursue from there.

If you think nothing good comes out of here, you should pay a lot more attention. Both here, and to the complete mess your buddy Franco is presiding over. We're getting serious work put into FreeBSD (passwd/group file corruption, AES-NI and AES-GCM, fixed DHCPv6 PD in ISC dhcpd port, just in the last month or so), have a power cycling chaos monkey proving we can now stand up to limitless back-to-back-to-back power cycles in worst-case file writing scenarios (where opnsense might last a handful, and probably 1-2 == dead box), while they still haven't fixed half the bugs we fixed between 2.2-BETA and 2.2.0-REL much less anything since and all the things they broke.

We're getting damn good stuff done. One of the future things you'll see is extremely high performance packet filtering. Which is ultimately what is needed for large scale DDoS handling purposes. While FreeBSD pf has improved significantly in performance over the years, and beats OpenBSD significantly on multi-core systems, there is still a lot of work to do there (or switch to a diff packet filter entirely) to make it multi-Mpps/new connections/sec capable.

Supermule

Thing is Chris… Franco is very kind to people.

I dont really dig into the opnsense/pfsense feud since its meaningless.

What I do mind, is that if people treat me nice, then I am nice to them and vice versa.

In regards to Opnsense, then I believe they are moving along quite nicely putting out a lot of updates very quickly. They chose a different path than ESF and thats about it.

kejianshi

You hired a power-cycling monkey? I'm pretty sure I'm qualified for that one…

phil.davis

How much power does the cycling monkey have?
Can it beat Chris Froome?
Should I hire it to pedal on the back of my tandem?