oss-sec mailing list archives

Re: shodan.io actively infiltrating ntp.org IPv6 pools for scanning purposes


From: "Zach W." <kestrel () trylinux us>
Date: Wed, 27 Jan 2016 09:23:26 -0800

I'm also not sure that having scanners scan and publish these results is
such a bad thing, it raises awareness, and hopfully long term leads to
things like legislation that forces device makers to make safe devices
(e.g. no web interface with password "Admin")

I agree with Kurt.

Having worked heavily with projects such as Shodan, I understand that
there are two sides to the coin. However, many issues have been brought
to light with such services that would otherwise not have been known to
the sec community.

I'm not sure if @achillean (John Matherly) is on oss-sec, but he is
always very forthcoming in dealing with these kinds of things. My
suggestion would be to reach out to him and find out.

Zach W.

On 1/27/2016 6:43 AM, Kurt Seifried wrote:
On Wed, Jan 27, 2016 at 4:24 AM, Luca BRUNO <lucab () debian org> wrote:

[cross-posted to pool-ntp and oss-sec]

Hi,
while reviewing network logs this morning I spotted some anomalies related
to scan probes, ntp.org pools and IPv6.

It looks like Brad already observed and blogged about this some days ago,
but I haven't seen this discussed in the usual ntp-pools, Debian and
oss-sec ML, so I'm reposting this here:

http://netpatterns.blogspot.de/2016/01/the-rising-sophistication-of-network.html

In summary, some machines (which seem related to the shodan.io scanning
project)
are actively participating in pool.ntp.org as IPv6 endpoints.
However, clients connecting to them for NTP timesync, are subsequently
scanned
by probes originating from *.scan6.shodan.io hosts.

Confirming original report from Brad, I can add that those scanners seem to
implement some kind of rate-limiting: they will timeout NTP and won't
re-scan
recent clients when doing multiple/subsequent NTP requests.
Moreover, this is not targeted/restricted to the Debian pool only, but
plague
the whole IPv6 pool, as seen on a sample query to the RedHat pool:

```
$ dig +short -t AAAA 2.rhel.pool.ntp.org | grep -E
':[[:xdigit:]]00[[:xdigit:]]$'
2a03:b0c0:3:d0::18:b001
$ dig +short -x 2a03:b0c0:3:d0::18:b001
analog.data.shodan.io.
```
(Upon querying this server for NTP, the machine immediately got
IPv6-scanned
by rock.scan6.shodan.io)

pool.ntp.org services are the default NTP servers in many default
configurations
(at least most of Linux distro) and I guess that this kind of behavior is
dangerously
increasing the exposure level of way too many systems.

For ntp.org admins: can those rogue server be expunged from the pools,
and the whole
shodan.io situation clarified? (Brad's post has a comprehensive endpoints
list and
helper tools for detection)

For oss-sec crowd: is there anything we can do to improve the situation
and avoid
similar cases in the future? Should crowd-sourced and fundamental services
like this
be encouraged to move to a stronger WoT?

Ciao, Luca

--
 .''`.  ** Debian GNU/Linux **  | Luca Bruno (kaeso)
: :'  :   The Universal O.S.    | lucab (AT) debian.org
`. `'`                          | GPG: 0xBB1A3A854F3BBEBF
  `-     http://www.debian.org  | Debian GNU/Linux Developer


Unfortunately there are strong economic incentives for this kind of
behavior. scanning is a great example, you want to scan the Internet of
things, this is easy with IPv4 (just bulk scan the used public space which
is like 3 billion IPs) and basically impossible with IPv6. Simply leverage
the fact that these IoT things often connect out to NTP servers by default
using the pool.ntp.org servers. No matter what you do on the ntp.org pool
the people who want to scan will most likely be willing to spend time and
money to get at that data (hosting ntp servers, sniffing traffic to them,
etc.). Sadly what you need is business process to detect this activity (and
other forms of shenanigans) and then deal with the offender (e.g. remove
their ntp server from the pool).

Sadly we can't really rely on the IoT device makers to fix this, they have
basically 0 incentive to prevent scanners from hitting their products
(they're already sold, to late for the customer to make an informed
decision).

I'm also not sure that having scanners scan and publish these results is
such a bad thing, it raises awareness, and hopfully long term leads to
things like legislation that forces device makers to make safe devices
(e.g. no web interface with password "Admin").



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