Re: Some new SSH exploit script?



On Mon, 5 Jun 2006, Michael Sierchio wrote:
Morning Wood wrote:

> I beg to differ with you -- running a standard service on a non-standard
> port is a bid for security through obscurity.

This wasnt implied as a full stop measure, but security through obscurity
coupled with other protections can enhance the overal security posture.
( not to mention stopping 99.9% of unauthorized traffic )

I don't see what the net effect is. You'll still see unauthorized connection

The net effect is (currently) that this silly attempts are no longer
spoiling the logfiles. On one host I moved my sshd to some other port
as well. Not because of security concerns but simply to better view my
log entries.

attempts by ankle-biters on port 22. If your implementation is vulnerable,

A syn coming in getting an rst. End of connection. From a single syn
I cannot tell if it is authorized or not unless I specify network ranges
that are allowed to get to my node on that port. In this case the other
side gets a port unreachable or nothing at all depending on how I restrict
access. A single syn doesn't worry me. An endless chain of syns to a
specific port will raise questions directed to the location the syns
originate from. But honestly, this only happens on rare occasions.

running a service on a non-standard port offers little-to-no protection.

Definitely. Being vulnerable is being vulnerable on any port you place
an application.

The number of TCP ports is very small, and the number of potential source
computers for a lazy and quiet scan to determine what service you're
running SSHD on is large. Are you going to change the service port on
a daily basis? Hourly?

For what? It's not necessary. Since the day I moved the port I just
saw one single attempt to connect to that host on that port, which does
not belong to the allowed ones. And that one checked it for being a web-
server.
Of course, things may/will chance over time.

Cheers,

Chris Kronberg.


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