NXDOMAIN data leakage prevention

[Amanda Constant]

I am out of the office October 1st & 2nd and will respond to your message as quickly as possible once I return.

Amanda

On Oct 1, 2018, at 11:27 AM, Amanda Constant via Unbound-users <unbound-users at nlnetlabs.nl> wrote:

> I am out of the office October 1st & 2nd and will respond to your message as quickly as possible once I return.
> 
> Amanda
> 
> On Oct 1, 2018, at 11:21 AM, Chris via Unbound-users <unbound-users at nlnetlabs.nl> wrote:
> 
> Welllll.... Ive done a lot of looking around and I just dont see any solution to this issue. Im not concerned with DoS attacks, those i could deal with. Im concerned for the stunningly stealthy 5 or 6 NXDOMAIN lookups from a scary actor. That kind of thing could transmit a small amount of really damaging info. Or.. A company using this to monitor each client with pings once a minute. The uses of this low rate communications channel is Unbounded and truly scary.
> 
> I know this has been around a long time. Im sorry for my stunned amazement, I just ran into this.
> 
> No matter how I rack my brain, I can't think of any way around this. Short of a registry of every domain before they can be used. So nothing should ever come up NXDOMAIN. Even then,, it will get abused.
> 
> Man, just when I thought I was happy with TLS 1.3 for DNS and DNSSEC. Its just never ending.
> 
> On 10/1/2018 4:03 AM, Chris via Unbound-users wrote:
> I was reading a disturbing article on ways that DNS can be used to get data past firewalls and for malicious programs to communicate with a command and control center via DNS NXDOMAIN.
> 
> Right off hand I dont see a way to block this ? Looking at my NXDOMAIN lookups its quite pervasive and coming from a large number of sources. Its clearly being used by A LOT of people.
> 
> Is there a way I can use Unbound to mitigate this threat ? This is a serious issue because i don't see how to block this.
> 
> https://www.plixer.com/blog/detecting-malware/security-vendors-teaching-bad-actors-how-to-get-past-firewalls/ 
> 
> 
> 
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