<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7036.0"> <TITLE>Security Breach?</TITLE> </HEAD> <BODY>  Hi all, hope you can help me out with this question I have just been sent which is as follows: - "We have had a security warning from the hosting company, one of the Nagios User processes was using up 90% of the CPU: 8521 nagios 25 0 6144 2168 1524 R 90.4 0.0 566:17.51 x A review of the users access logs show this appeared to start last night, and the account has been remotely logged in to, suggesting its fully compromised: nagios pts/3 :pts/1:S.0 Sat Apr 3 11:35 - 11:36 (00:00) nagios pts/3 :pts/1:S.0 Sat Apr 3 11:32 - 11:35 (00:03) nagios pts/3 :pts/1:S.0 Sat Apr 3 01:41 - 11:30 (09:49) nagios pts/1 79.119.233.48 Sat Apr 3 01:36 - 15:36 (13:59) nagios pts/3 :pts/1:S.0 Fri Apr 2 23:50 - 01:36 (01:45) nagios pts/3 :pts/1:S.0 Fri Apr 2 22:25 - 23:37 (01:12) nagios pts/1 79.119.233.48 Fri Apr 2 20:55 - 01:36 (04:41) nagios pts/3 :pts/1:S.0 Fri Apr 2 12:47 - 13:18 (00:31) nagios pts/3 :pts/1:S.0 Fri Apr 2 10:50 - 12:47 (01:56) nagios pts/3 :pts/1:S.0 Fri Apr 2 10:49 - 10:49 (00:00) nagios pts/2 :pts/1:S.0 Fri Apr 2 10:36 - 10:49 (00:12) nagios pts/2 :pts/1:S.0 Fri Apr 2 10:02 - 10:36 (00:33) nagios pts/1 79.119.227.50 Fri Apr 2 09:35 - 13:18 (03:43) nagios pts/1 91.194.84.177 Fri Apr 2 01:52 - 01:52 (00:00" Could you help me out to try and understand how this has happened please as I'm at a complete loss, if you need more info I will endeavour to get it for you. Thanks all Nrpe.cfg and hosts allow are below. ###################################################### # LOG FACILITY # The syslog facility that should be used for logging purposes. log_facility=daemon # PID FILE # The name of the file in which the NRPE daemon should write it's process ID # number. The file is only written if the NRPE daemon is started by the root # user and is running in standalone mode. pid_file=/var/run/nrpe.pid # PORT NUMBER # Port number we should wait for connections on. # NOTE: This must be a non-priviledged port (i.e. > 1024). # NOTE: This option is ignored if NRPE is running under either inetd or xinetd server_port=5666 # SERVER ADDRESS # Address that nrpe should bind to in case there are more than one interface # and you do not want nrpe to bind on all interfaces. # NOTE: This option is ignored if NRPE is running under either inetd or xinetd #server_address=127.0.0.1 # NRPE USER # This determines the effective user that the NRPE daemon should run as. # You can either supply a username or a UID. # # NOTE: This option is ignored if NRPE is running under either inetd or xinetd nrpe_user=nagios # NRPE GROUP # This determines the effective group that the NRPE daemon should run as. # You can either supply a group name or a GID. # # NOTE: This option is ignored if NRPE is running under either inetd or xinetd nrpe_group=nagios # ALLOWED HOST ADDRESSES # This is an optional comma-delimited list of IP address or hostnames # that are allowed to talk to the NRPE daemon. # # Note: The daemon only does rudimentary checking of the client's IP # address. I would highly recommend adding entries in your /etc/hosts.allow # file to allow only the specified host to connect to the port # you are running this daemon on. # # NOTE: This option is ignored if NRPE is running under either inetd or xinetd allowed_hosts=127.0.0.1 # COMMAND ARGUMENT PROCESSING # This option determines whether or not the NRPE daemon will allow clients # to specify arguments to commands that are executed. This option only works # if the daemon was configured with the --enable-command-args configure script # option. # # *** ENABLING THIS OPTION IS A SECURITY RISK! *** # Read the SECURITY file for information on some of the security implications # of enabling this variable. # # Values: 0=do not allow arguments, 1=allow command arguments dont_blame_nrpe=0 # COMMAND PREFIX # This option allows you to prefix all commands with a user-defined string. # A space is automatically added between the specified prefix string and the # command line from the command definition. # # *** THIS EXAMPLE MAY POSE A POTENTIAL SECURITY RISK, SO USE WITH CAUTION! *** # Usage scenario: # Execute restricted commmands using sudo. For this to work, you need to add # the nagios user to your /etc/sudoers. An example entry for alllowing # execution of the plugins from might be: # # nagios ALL=(ALL) NOPASSWD: /usr/lib/nagios/plugins/ # # This lets the nagios user run all commands in that directory (and only them) # without asking for a password. If you do this, make sure you don't give # random users write access to that directory or its contents! # command_prefix=/usr/bin/sudo # DEBUGGING OPTION # This option determines whether or not debugging messages are logged to the # syslog facility. # Values: 0=debugging off, 1=debugging on debug=0 # COMMAND TIMEOUT # This specifies the maximum number of seconds that the NRPE daemon will # allow plugins to finish executing before killing them off. command_timeout=60 # CONNECTION TIMEOUT # This specifies the maximum number of seconds that the NRPE daemon will # wait for a connection to be established before exiting. This is sometimes # seen where a network problem stops the SSL being established even though # all network sessions are connected. This causes the nrpe daemons to # accumulate, eating system resources. Do not set this too low. connection_timeout=300 # WEEK RANDOM SEED OPTION # This directive allows you to use SSL even if your system does not have # a /dev/random or /dev/urandom (on purpose or because the necessary patches # were not applied). The random number generator will be seeded from a file # which is either a file pointed to by the environment valiable $RANDFILE # or $HOME/.rnd. If neither exists, the pseudo random number generator will # be initialized and a warning will be issued. # Values: 0=only seed from /dev/[u]random, 1=also seed from weak randomness #allow_weak_random_seed=1 # INCLUDE CONFIG FILE # This directive allows you to include definitions from an external config file. #include=<somefile.cfg> # INCLUDE CONFIG DIRECTORY # This directive allows you to include definitions from config files (with a # .cfg extension) in one or more directories (with recursion). #include_dir=<somedirectory> #include_dir=<someotherdirectory> # COMMAND DEFINITIONS # Command definitions that this daemon will run. Definitions # are in the following format: # # command[<command_name>]=<command_line> # # When the daemon receives a request to return the results of <command_name> # it will execute the command specified by the <command_line> argument. # # Unlike Nagios, the command line cannot contain macros - it must be # typed exactly as it should be executed. # # Note: Any plugins that are used in the command lines must reside # on the machine that this daemon is running on! The examples below # assume that you have plugins installed in a /usr/local/nagios/libexec # directory. Also note that you will have to modify the definitions below # to match the argument format the plugins expect. Remember, these are # examples only! # The following examples use hardcoded command arguments... command[check_users]=/usr/local/nagios/libexec/check_users -w 5 -c 10 command[check_load]=/usr/local/nagios/libexec/check_load -w 35,30,25 -c 50,45,40 command[check_hda1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/hda1 command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 1500 -c 2000 command[check_disk1]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/sda3 command[check_disk2]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p /dev/sda1 command[check_disk3]=/usr/local/nagios/libexec/check_disk -w 20% -c 10% -p tmpfscommand[check_local_swap]=/usr/local/nagios/libexec/check_swap -w 20% -c 10% command[check_local_swap]=/usr/local/nagios/libexec/check_swap -w 20% -c 10% #command[check_users]=/usr/local/nagios/libexec/check_users -w $ARG1$ -c $ARG2$ #command[check_load]=/usr/local/nagios/libexec/check_load -w $ARG1$ -c $ARG2$ #command[check_disk]=/usr/local/nagios/libexec/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$ #command[check_procs]=/usr/local/nagios/libexec/check_procs -w $ARG1$ -c $ARG2$ -s $ARG3$ hosts.allow # # hosts.allow This file describes the names of the hosts which are # allowed to use the local INET services, as decided # by the '/usr/sbin/tcpd' server. # nrpe: 17.0.0.1 xxx.27.117.xxx </BODY> </HTML>