Server hacked on known port Post: 303029984

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Special Forums Cybersecurity Server hacked on known port Post 303029984 by bakunin on Monday 4th of February 2019 06:37:06 AM

02-04-2019

Registered User

If i remember correctly 1521 is one of the standard ports for the Oracle listener, so i suppose you have an Oracle database running there. That the listener listens is quite as it should be, no?

What makes you think the server "was hacked"?

I mean, iptables is just a packet filter and as such it cannot discern between legitimate content and an illegitimate one. It filters packets based on IP address (layer 3) and port (layer 4), nothing more, nothing less. Obviously you need to allow traffic to the configured port of the listener otherwise the database would not be usable. So either you allow this port or you disable it (eventually restricting to a certain range of IP addresses), but what content goes over this port (i.e. legitimate database queries vs. malicious content) the packet filter is the wrong tool to assess. For that you will need a "stateful inspection" type of firewall which iptables is not.

Also be aware that the concept of "host based firewalls" is a flawed one per design. A hosts role is either providing a service (that is: some application) OR providing firewall services, but not both! The reason is you don't want the host you want to protect run the firewall itself, beause in this scenario the malicious packages already have reached the interface they are trying to attack. You want the firewall in front of (and separated from) the host you try to protect so that the malicious content doesn't even reach the interface you want to protect.

I hope this helps.

bakunin

Last edited by bakunin; 02-04-2019 at 05:08 PM.. Reason: confused "stateful inspection" with "deep state inspection" - oh, the paranoia

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ka-forwarder

KA-FORWARDER(8) 					       AFS Command Reference						   KA-FORWARDER(8)

NAME

       ka-forwarder - Forward AFS Authentication Server requests to another server

SYNOPSIS

       ka-forwarder [-p <port>] <server>[/<port>] [...]

DESCRIPTION

       ka-forwarder listens for requests for an AFS Authentication Server and forwards them to a remove fakeka server.	fakeka is a server that
       answers AFS Authentication Server protocol requests using a regular Kerberos KDC and is provided with some Kerberos 5 implementations.
       fakeka has to run on the same host as the Kerberos KDC, however, and AFS clients send all native AFS authentication requests to the AFS
       database servers.  If you don't want to run your Kerberos KDCs and your AFS database servers on the same host, run ka-forwarder on the AFS
       database servers and point it to fakeka running on the Kerberos KDCs.

       ka-forwarder takes one or more servers to which to forward the requests.  The default port on the remote server to which to forward the
       command is 7004, but a different port can be specified by following the server name with a slash ("/") and the port number.  If multiple
       servers are given, ka-forwarder will send queries to each server in turn in a round-robin fashion.

CAUTIONS

       Due to the way that ka-forwarder distinguishes from client requests and server responses, any messages from one of the servers to which ka-
       forwarder is forwarding will be considered a reply rather than a command and will not be forwarded.  This means that the servers running
       fakeka will not be able to use native AFS authentication requests and rely on ka-forwarder to send the requests to the right server.

       ka-forwarder does not background itself.  It should either be run in the background via the shell, or run via the Basic OverSeer Server
       (see bosserver(8)).

OPTIONS

       -p <port>
	   By default, ka-forwarder listens to the standard AFS Authentication Server port (7004).  To listen to a different port, specify it with
	   the -p option.

EXAMPLES

       Forward AFS Authentication Server requests to the fakeka servers on kdc1.example.com and kdc2.example.com:

	   % ka-forwarder kdc1.example.com kdc2.example.com &

       Note the "&" to tell the shell to run this command in the background.

PRIVILEGE REQUIRED

       ka-forwarder only has to listen to port 7004 and therefore does not require any special privileges unless a privileged port is specified
       with the -p option.

SEE ALSO

       bosserver(8), fakeka(8), kaserver(8)

COPYRIGHT

       Copyright 2006 Russ Allbery <rra@stanford.edu>

       This documentation is covered by the IBM Public License Version 1.0.  This man page was written by Russ Allbery for OpenAFS.

OpenAFS 							    2012-03-26							   KA-FORWARDER(8)