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 11:33 AM, John Peacock via Unbound-users <[email protected]> wrote: > It's not just NXDOMAIN; this exfiltration vector is simply a fact of life > with a distributed "database" like DNS. For example, consider a synthetic > CNAME query from an already infected system that encodes dynamic information > in the query itself; then the answer to the CNAME could be updated > instructions for the exploit code. > > You'd almost have to log all queries and try to analyze them on the fly for > anything that was "suspicious". > > John > > On Mon, Oct 1, 2018 at 1:22 PM Chris via Unbound-users > <[email protected]> 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/ > > > > > > > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please visit http://www.symanteccloud.com > ______________________________________________________________________
