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-
Of course, things may/will chance over time.


Chris Kronberg.

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Relevant Pages

  • RE: Re: Concepts: Security and Obscurity
    ... so long as you understand that the server location and port number ... security in the slightest." ... Beale's assertion that "Obscurity Potentially Slows Down the Attacker". ... BDO Kendalls is a national association of separate partnerships and entities. ...
  • RE: Re: Concepts: Security and Obscurity
    ... BDO Kendalls is a national association of separate partnerships and entities. ... last I heard availability had something to do with security. ... Maybe we can all agree that "port obscurity" is a special case of STO. ...
  • Re: Some new SSH exploit script?
    ... So for those small sites or sites only allowing ssh in for specific persons such as a few admin and perhaps a few application maintainers, and even a vendor or two, we find it easier to maintain the standard port and restrict access in the firewall and tcpd to specific addresses, and on occasion users via sshd_config settings as well. ... Log cruft is a pretty lame reason and rational for making a choice to implement a non-standard port setting, admins should have the skills to filter and parse logs in a manner such that the cruft does not interfere with their daily log monitoring chores, else they have likely a lot of other cruft that must as well be driving them to near madness as well not relating to sshd and the kiddie brute-forcing tool of the week. ... I believe in security in-depth, but this depth is so superficial, I ... Download FREE whitepaper on how a managed service can ...
  • Re: Re: Concepts: Security and Obscurity
    ... Then you must admit port obscurity is a special case, ... BDO Kendalls is a national association of separate partnerships and entities. ... Subject: Concepts: Security and Obscurity ...
  • and frequently asked questions
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