Re: Syslog over Internet

[Damian Menscher <menscher () uiuc edu>]

On Mon, 18 Aug 2003, Vineet Mehta wrote:

> I have hired a server located in a different country. I heard that its
> better to log all your syslog messages on a different machine. As i dont
> have access to any other machine on that network except in my own
> country.
>
> My question is how safe and efficient it is to log Syslogd messages from
> my server in other country to my server in this country?
>
> Is it really safe? is it adviced to do so, of not then why?

The reason to do it is so an intruder can't remove evidence of their
attack, since the evidence will be stored elsewhere.  Normally, this is
a good thing to do, if you want to be able to trace suspected
intrusions.

In your case, however, I don't recommend doing it in the default
configuration.  The problem is that syslog messages are typically sent
in plaintext (over port 514/udp).  And it's possible for logs to contain
sensitive information.  For example, what if you accidentally type your
password at a login prompt?  It will log a failed login attempt from
unauthorized user <password>.  Therefore your password will be sent
across the internet in plaintext!

It is possible to pipe syslog messages through a program (often used for
advanced log filtering).  In your case, you might consider piping them
through a program that encrypts them before sending them over the wire.
Be advised that the encryption algorithm should be secure against
known-, chosen-, or repeated-plaintext attacks, since all log messages
begin the same way, and an attacker can induce certain error messages to
appear.

Damian Menscher
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