tiger 1:3.2.3-14 / usr / lib / tiger / doc / known.html

<HR><PRE>








</PRE><HR>
<CENTER><H2> Documents for known</H2></CENTER>
<A NAME="kis001a"><P><B>Code [kis001a]</B><P>
The indicated file is a directory. The file is a known location used
by intruders. This should be considered a sign that this system
has been compromised. The system should be checked for other signs
of intrusion and cleaned up.
<PRE>










</PRE><HR>
<A NAME="kis002a"><P><B>Code [kis002a]</B><P>
The indicated file is a known location used by intruders. This should
be considered a sign that this system has been compromised. The system
should be checked for other signs of intrusion and cleaned up.
<PRE>










</PRE><HR>
<A NAME="kis003a"><P><B>Code [kis003a]</B><P>
The indicated window server directory contains files other than UNIX
data-gram sockets. This should be considered a sign that this system
has been compromised. The system should be checked for other signs
of intrusion and cleaned up.
<PRE>










</PRE><HR>
<A NAME="kis004w"><P><B>Code [kis004w]</B><P>
The 'lost+found' directory (one exists for each file system) is used
by the `fsck' program as a directory for re-linking "dangling" files
during the file system check. These directories should be checked when
a file system check is not clean and files recovered from here. This
directory is also used by intruders to store files, as it is often
ignored. The files found here should be checked. If any unusual files
are found, the system should be checked for other signs of intrusion.
In any event, the 'lost+found' directories should be kept clean.
<PRE>










</PRE><HR>
<A NAME="kis005a"><P><B>Code [kis005a]</B><P>
The /bin/login program appears to have a back-door installed. The
program should be compared against distribution media and replaced
if it has been altered. The system should be checked for other
signs of intrusion and cleaned.
<PRE>










</PRE><HR>
<A NAME="kis006e"><P><B>Code [kis006e]</B><P>
The attempt to compile the program to check the setuid() system
call failed for some reason. This will prevent the test from
occurring.
<PRE>










</PRE><HR>
<A NAME="kis007a"><P><B>Code [kis007a]</B><P>
The setuid() system call succeeded even though the user was not
root. This most likely indicates that the system has been compromised
and the OS altered. A new kernel should be installed and the machine
rebooted.
<PRE>










</PRE><HR>
<A NAME="kis008w"><P><B>Code [kis008w]</B><P>
The indicated file in the system mail spool does not have a name which
matches the owner. This indicates either an attempt to create a mailbox
for another user (allowing someone else to read that persons mail),
or that the mail spool is being used to store files. These files should
be checked, and if unusual, the system should be examined for other signs
of intrusion.
<PRE>










</PRE><HR>
<A NAME="kis009w"><P><B>Code [kis009w]</B><P>
There is an .exrc file outside of any user's home directory. This file can
be loaded inadvertently by a user if executing an editor in that directory
and could introduce unexpected commands through it.
Note that in all modern versions of vi, you have to set the exrc option
in your home's directory .exrc file before vi will read the exrc in
the current directory (using 'set exrc').
If you are using an old version of vi or users have this option enabled,
however, commands in .exrc might compromise the security of your system.
<PRE>










</PRE><HR>
<A NAME="kis010w"><P><B>Code [kis010w]</B><P>
The indicated file in the system mail spool does not belong to any user
in the system. This might indicate that a user has been removed but not his
mailbox or that this mailbox has been created wrongly. These files should
be checked and, if belonging to former users, removed.
(Note: this warning will be given too if, for some reason, the user running
Tiger cannot access the user database)
<PRE>










</PRE><HR>
<A NAME="kis011f"><P><B>Code [kis011f]</B><P>
A server in the system (that is, a process with a listening socket towards
the Internet) or its parent process has an open file which has been removed
from the system. This might be a usual behaviour in the process or it might
be an indication of an intruder that has executed a backdoor in the system
(which opens a connection to accept requests from the Internet) and has
later removed the program from the system so that it cannot be traced back
to him.
This also can happen if a local service is using shared libraries which have
been upgraded but the service itself has not been restarted in order to
use the new libraries. Notice that if there was a vulnerability in the
library and the server is not restarted the system is still vulnerable.
<PRE>










</PRE><HR>
<A NAME="kis012w"><P><B>Code [kis012w]</B><P>
An application in the system is using a deleted file. This might be an
indication of an intruder executing rogue processes and removing the files
from disk so that they cannot be traced or detected by the local administrator.
This has been observed both in intruders running password cracking programs
or worms propagating through remote attacks.
This also can happen if a local application is using shared libraries which have
been upgraded but the service itself has not been restarted in order to
use the new libraries. Notice that if there was a vulnerability in the
library and the server was not restarted the system is still vulnerable.
<PRE>










</PRE><HR>
<A NAME="kis013a"><P><B>Code [kis013a]</B><P>
A interface is set up on promiscuous mode, this is a common method
used by attackers to capture user account and and password information.
For related information, see CERT advisory CA-94:01 available in
http://www.cert.org/advisories/CA-94.01.ongoing.network.monitoring.attacks.html
<PRE>










</PRE><HR>
<A NAME="kis014a"><P><B>Code [kis014a]</B><P>
A shell entry (/bin/sh or /bin/csh) has been defined in inetd.conf, this is
a common method used by attackers to introduce system backdoors and may
exploits run the following code:
<P>
echo 'ingreslock stream tcp nowait root /bin/sh sh -i' > /tmp/bob; /usr/sbin/inetd -s /tmp/bob
<P>
You should check all if the inetd running in the system is using a modified
configuration file and check all the programs specified in either that
configuration file or /etc/inetd.conf to verify that they are correct
and have not been replaced by Trojan horse programs.
Also check for legitimate services that you have commented
out in your /etc/inetd.conf. Intruders may turn on a service
that you previously thought you had turned off, or replace
the inetd program with a Trojan horse program.