[louisk@bend.com: snort, postgres, bridge]
From: Louis Kowolowski (louisk_at_bend.com)
Date: 08/28/03
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Date: Thu, 28 Aug 2003 12:21:51 -0700 To: freebsd-security@freebsd.org
----- Forwarded message from Louis Kowolowski <louisk@bend.com> -----
Date: Thu, 28 Aug 2003 11:37:42 -0700
From: Louis Kowolowski <louisk@bend.com>
To: freebsd-security@freebsd.org
Subject: snort, postgres, bridge
User-Agent: Mutt/1.5.4i
I've been prowling through the FreeBSD and Snort list archives in
search of information on setting up snort on a FreeBSD bridge(4)
that logs to a remote postgres box via a third interface (hme0)
Snort is being started with the following command:
/usr/local/bin/snort -A full -D -e -d -s -i fxp0 -c /usr
/local/etc/snort.conf
Where fxp0 and fxp1 are in the bridge
output from sysctl:
net.link.ether.bridge_cfg: fxp0:0,fxp1:0
net.link.ether.bridge: 1
net.link.ether.bridge_ipfw: 0
net.link.ether.bridge_ipf: 1
net.link.ether.bridge_ipfw_drop: 0
net.link.ether.bridge_ipfw_collisions: 0
The snort.conf is attached. I've attempted to start with a pretty
generic config, just to ensure things work.
The problem appears to be that snort simply doesn't log to the remote
postgres box (yes, there are host entries in pg_hba.conf, and other
databases are accessible remotely, so I believe that is not the issue).
I've just been running trafshow to watch connections.
Any hints/pointers/solutions welcome.
Thanks
-- ----- End forwarded message ----- Appending snort.conf: #-------------------------------------------------- # http://www.snort.org Snort 2.0.0 Ruleset # Contact: snort-sigs@lists.sourceforge.net #-------------------------------------------------- # $Id: snort.conf,v 1.124 2003/05/16 02:52:41 cazz Exp $ # ################################################### # This file contains a sample snort configuration. # You can take the following steps to create your # own custom configuration: # # 1) Set the network variables for your network # 2) Configure preprocessors # 3) Configure output plugins # 4) Customize your rule set # ################################################### # Step #1: Set the network variables: # # You must change the following variables to reflect # your local network. The variable is currently # setup for an RFC 1918 address space. # # You can specify it explicitly as: # # var HOME_NET 10.1.1.0/24 # # or use global variable $<interfacename>_ADDRESS # which will be always initialized to IP address and # netmask of the network interface which you run # snort at. Under Windows, this must be specified # as $(<interfacename>_ADDRESS), such as: # $(\Device\Packet_{12345678-90AB-CDEF-1234567890AB}_ADDRESS) # # var HOME_NET $eth0_ADDRESS # # You can specify lists of IP addresses for HOME_NET # by separating the IPs with commas like this: # # var HOME_NET [10.1.1.0/24,192.168.1.0/24] # # MAKE SURE YOU DON'T PLACE ANY SPACES IN YOUR LIST! # # or you can specify the variable to be any IP address # like this: var HOME_NET any # Set up the external network addresses as well. # A good start may be "any" var EXTERNAL_NET any # Configure your server lists. This allows snort to only look for attacks # to systems that have a service up. Why look for HTTP attacks if you are # not running a web server? This allows quick filtering based on IP addresses # These configurations MUST follow the same configuration scheme as defined # above for $HOME_NET. # List of DNS servers on your network var DNS_SERVERS $HOME_NET # List of SMTP servers on your network var SMTP_SERVERS $HOME_NET # List of web servers on your network var HTTP_SERVERS $HOME_NET # List of sql servers on your network var SQL_SERVERS $HOME_NET # List of telnet servers on your network var TELNET_SERVERS $HOME_NET # Configure your service ports. This allows snort to look for attacks # destined to a specific application only on the ports that application # runs on. For example, if you run a web server on port 8081, set your # HTTP_PORTS variable like this: # # var HTTP_PORTS 8010 # # Port lists must either be continuous [eg 80:8080], or a single port [eg 80]. # We will adding support for a real list of ports in the future. # Ports you run web servers on var HTTP_PORTS 80 # Ports you want to look for SHELLCODE on. var SHELLCODE_PORTS !80 # Ports you do oracle attacks on var ORACLE_PORTS 1521 # other variables # # AIM servers. AOL has a habit of adding new AIM servers, so instead of # modifying the signatures when they do, we add them to this list of # servers. var AIM_SERVERS [64.12.24.0/24,64.12.25.0/24,64.12.26.14/24,64.12.28.0/24,64.12.29.0/24,64.12.161.0/24,64.12.163.0/24,205.188.5.0/24,205.188.9.0/24] # Path to your rules files (this can be a relative path) var RULE_PATH ../share/snort # Configure the snort decoder: # ============================ # # Stop generic decode events: # # config disable_decode_alerts # # Stop Alerts on experimental TCP options # # config disable_tcpopt_experimental_alerts # # Stop Alerts on obsolete TCP options # # config disable_tcpopt_obsolete_alerts # # Stop Alerts on T/TCP alerts # # config disable_ttcp_alerts # # Stop Alerts on all other TCPOption type events: # # config disable_tcpopt_alerts # # Stop Alerts on invalid ip options # # config disable_ipopt_alerts # Configure the detection engine # =============================== # # Use a different pattern matcher in case you have a machine with very # limited resources: # # config detection: search-method lowmem ################################################### # Step #2: Configure preprocessors # # General configuration for preprocessors is of # the form # preprocessor <name_of_processor>: <configuration_options> # frag2: IP defragmentation support # ------------------------------- # This preprocessor performs IP defragmentation. This plugin will also detect # people launching fragmentation attacks (usually DoS) against hosts. No # arguments loads the default configuration of the preprocessor, which is a # 60 second timeout and a 4MB fragment buffer. # The following (comma delimited) options are available for frag2 # timeout [seconds] - sets the number of [seconds] than an unfinished # fragment will be kept around waiting for completion, # if this time expires the fragment will be flushed # memcap [bytes] - limit frag2 memory usage to [number] bytes # (default: 4194304) # # min_ttl [number] - minimum ttl to accept # # ttl_limit [number] - difference of ttl to accept without alerting # will cause false positves with router flap # # Frag2 uses Generator ID 113 and uses the following SIDS # for that GID: # SID Event description # ----- ------------------- # 1 Oversized fragment (reassembled frag > 64k bytes) # 2 Teardrop-type attack preprocessor frag2 # stream4: stateful inspection/stream reassembly for Snort #---------------------------------------------------------------------- # Use in concert with the -z [all|est] command line switch to defeat # stick/snot against TCP rules. Also performs full TCP stream # reassembly, stateful inspection of TCP streams, etc. Can statefully # detect various portscan types, fingerprinting, ECN, etc. # stateful inspection directive # no arguments loads the defaults (timeout 30, memcap 8388608) # options (options are comma delimited): # detect_scans - stream4 will detect stealth portscans and generate alerts # when it sees them when this option is set # detect_state_problems - detect TCP state problems, this tends to be very # noisy because there are a lot of crappy ip stack # implementations out there # # disable_evasion_alerts - turn off the possibly noisy mitigation of # overlapping sequences. # # # min_ttl [number] - set a minium ttl that snort will accept to # stream reassembly # # ttl_limit [number] - differential of the initial ttl on a session versus # the normal that someone may be playing games. # Routing flap may cause lots of false positives. # # keepstats [machine|binary] - keep session statistics, add "machine" to # get them in a flat format for machine reading, add # "binary" to get them in a unified binary output # format # noinspect - turn off stateful inspection only # timeout [number] - set the session timeout counter to [number] seconds, # default is 30 seconds # memcap [number] - limit stream4 memory usage to [number] bytes # log_flushed_streams - if an event is detected on a stream this option will # cause all packets that are stored in the stream4 # packet buffers to be flushed to disk. This only # works when logging in pcap mode! # # Stream4 uses Generator ID 111 and uses the following SIDS # for that GID: # SID Event description # ----- ------------------- # 1 Stealth activity # 2 Evasive RST packet # 3 Evasive TCP packet retransmission # 4 TCP Window violation # 5 Data on SYN packet # 6 Stealth scan: full XMAS # 7 Stealth scan: SYN-ACK-PSH-URG # 8 Stealth scan: FIN scan # 9 Stealth scan: NULL scan # 10 Stealth scan: NMAP XMAS scan # 11 Stealth scan: Vecna scan # 12 Stealth scan: NMAP fingerprint scan stateful detect # 13 Stealth scan: SYN-FIN scan # 14 TCP forward overlap preprocessor stream4: detect_scans, disable_evasion_alerts # tcp stream reassembly directive # no arguments loads the default configuration # Only reassemble the client, # Only reassemble the default list of ports (See below), # Give alerts for "bad" streams # # Available options (comma delimited): # clientonly - reassemble traffic for the client side of a connection only # serveronly - reassemble traffic for the server side of a connection only # both - reassemble both sides of a session # noalerts - turn off alerts from the stream reassembly stage of stream4 # ports [list] - use the space separated list of ports in [list], "all" # will turn on reassembly for all ports, "default" will turn # on reassembly for ports 21, 23, 25, 53, 80, 143, 110, 111 # and 513 preprocessor stream4_reassemble # http_decode: normalize HTTP requests # ------------------------------------ # http_decode normalizes HTTP requests from remote # machines by converting any %XX character # substitutions to their ASCII equivalent. This is # very useful for doing things like defeating hostile # attackers trying to stealth themselves from IDSs by # mixing these substitutions in with the request. # Specify the port numbers you want it to analyze as arguments. # # Major code cleanups thanks to rfp # # unicode - normalize unicode # iis_alt_unicode - %u encoding from iis # double_encode - alert on possible double encodings # iis_flip_slash - normalize \ as / # full_whitespace - treat \t as whitespace ( for apache ) # # for that GID: # SID Event description # ----- ------------------- # 1 UNICODE attack # 2 NULL byte attack preprocessor http_decode: 80 unicode iis_alt_unicode double_encode iis_flip_slash full_whitespace # rpc_decode: normalize RPC traffic # --------------------------------- # RPC may be sent in alternate encodings besides the usual # 4-byte encoding that is used by default. This preprocessor # normalized RPC traffic in much the same way as the http_decode # preprocessor. This plugin takes the ports numbers that RPC # services are running on as arguments. # The RPC decode preprocessor uses generator ID 106 # # arguments: space separated list # alert_fragments - alert on any rpc fragmented TCP data # no_alert_multiple_requests - don't alert when >1 rpc query is in a packet # no_alert_large_fragments - don't alert when the fragmented # sizes exceed the current packet size # no_alert_incomplete - don't alert when a single segment # exceeds the current packet size preprocessor rpc_decode: 111 32771 # bo: Back Orifice detector # ------------------------- # Detects Back Orifice traffic on the network. Takes no arguments in 2.0. # # The Back Orifice detector uses Generator ID 105 and uses the # following SIDS for that GID: # SID Event description # ----- ------------------- # 1 Back Orifice traffic detected preprocessor bo # telnet_decode: Telnet negotiation string normalizer # --------------------------------------------------- # This preprocessor "normalizes" telnet negotiation strings from # telnet and ftp traffic. It works in much the same way as the # http_decode preprocessor, searching for traffic that breaks up # the normal data stream of a protocol and replacing it with # a normalized representation of that traffic so that the "content" # pattern matching keyword can work without requiring modifications. # This preprocessor requires no arguments. # Portscan uses Generator ID 109 and does not generate any SID currently. preprocessor telnet_decode # Portscan: detect a variety of portscans # --------------------------------------- # portscan preprocessor by Patrick Mullen <p_mullen@linuxrc.net> # This preprocessor detects UDP packets or TCP SYN packets going to # four different ports in less than three seconds. "Stealth" TCP # packets are always detected, regardless of these settings. # Portscan uses Generator ID 100 and uses the following SIDS for that GID: # SID Event description # ----- ------------------- # 1 Portscan detect # 2 Inter-scan info # 3 Portscan End # preprocessor portscan: $HOME_NET 4 3 portscan.log # Use portscan-ignorehosts to ignore TCP SYN and UDP "scans" from # specific networks or hosts to reduce false alerts. It is typical # to see many false alerts from DNS servers so you may want to # add your DNS servers here. You can all multiple hosts/networks # in a whitespace-delimited list. # #preprocessor portscan-ignorehosts: 0.0.0.0 # arpspoof #---------------------------------------- # Experimental ARP detection code from Jeff Nathan, detects ARP attacks, # unicast ARP requests, and specific ARP mapping monitoring. To make use # of this preprocessor you must specify the IP and hardware address of hosts on # the same layer 2 segment as you. Specify one host IP MAC combo per line. # Also takes a "-unicast" option to turn on unicast ARP request detection. # Arpspoof uses Generator ID 112 and uses the following SIDS for that GID: # SID Event description # ----- ------------------- # 1 Unicast ARP request # 2 Etherframe ARP mismatch (src) # 3 Etherframe ARP mismatch (dst) # 4 ARP cache overwrite attack #preprocessor arpspoof #preprocessor arpspoof_detect_host: 192.168.40.1 f0:0f:00:f0:0f:00 # Conversation #------------------------------------------ # This preprocessor tracks conversations for tcp, udp and icmp traffic. It # is a prerequisite for running portscan2. # # allowed_ip_protcols 1 6 17 # list of allowed ip protcols ( defaults to any ) # # timeout [num] # conversation timeout ( defaults to 60 ) # # # max_conversations [num] # number of conversations to support at once (defaults to 65335) # # # alert_odd_protocols # alert on protocols not listed in allowed_ip_protocols # # preprocessor conversation: allowed_ip_protocols all, timeout 60, max_conversations 3000 # # Portscan2 #------------------------------------------- # Portscan 2, detect portscans in a new and exciting way. You must enable # spp_conversation in order to use this preprocessor. # # Available options: # scanners_max [num] # targets_max [num] # target_limit [num] # port_limit [num] # timeout [num] # log [logdir] # #preprocessor portscan2: scanners_max 256, targets_max 1024, target_limit 5, port_limit 20, timeout 60 # Too many false alerts from portscan2? Tone it down with # portscan2-ignorehosts! # # A space delimited list of addresses in CIDR notation to ignore # # preprocessor portscan2-ignorehosts: 10.0.0.0/8 192.168.24.0/24 # # Experimental Perf stats # ----------------------- # No docs. Highly subject to change. # # preprocessor perfmonitor: console flow events time 10 #################################################################### # Step #3: Configure output plugins # # Uncomment and configure the output plugins you decide to use. # General configuration for output plugins is of the form: # # output <name_of_plugin>: <configuration_options> # # alert_syslog: log alerts to syslog # ---------------------------------- # Use one or more syslog facilities as arguments. Win32 can also # optionally specify a particular hostname/port. Under Win32, the # default hostname is '127.0.0.1', and the default port is 514. # # [Unix flavours should use this format...] # output alert_syslog: LOG_AUTH LOG_ALERT # # [Win32 can use any of these formats...] # output alert_syslog: LOG_AUTH LOG_ALERT # output alert_syslog: host=hostname, LOG_AUTH LOG_ALERT # output alert_syslog: host=hostname:port, LOG_AUTH LOG_ALERT # log_tcpdump: log packets in binary tcpdump format # ------------------------------------------------- # The only argument is the output file name. # # output log_tcpdump: tcpdump.log # database: log to a variety of databases # --------------------------------------- # See the README.database file for more information about configuring # and using this plugin. # # output database: log, mysql, user=root password=test dbname=db host=localhost output database: log, postgresql, sensor_name=externalfirewall encoding=hex port=5432 user=snort dbname=snort host=postgres.csia.sou.edu # output database: alert, postgresql, user=snort dbname=snort # output database: log, unixodbc, user=snort dbname=snort # output database: log, mssql, dbname=snort user=snort password=test # unified: Snort unified binary format alerting and logging # ------------------------------------------------------------- # The unified output plugin provides two new formats for logging # and generating alerts from Snort, the "unified" format. The # unified format is a straight binary format for logging data # out of Snort that is designed to be fast and efficient. Used # with barnyard (the new alert/log processor), most of the overhead # for logging and alerting to various slow storage mechanisms # such as databases or the network can now be avoided. # # Check out the spo_unified.h file for the data formats. # # Two arguments are supported. # filename - base filename to write to (current time_t is appended) # limit - maximum size of spool file in MB (default: 128) # # output alert_unified: filename snort.alert, limit 128 # output log_unified: filename snort.log, limit 128 # You can optionally define new rule types and associate one or # more output plugins specifically to that type. # # This example will create a type that will log to just tcpdump. # ruletype suspicious # { # type log # output log_tcpdump: suspicious.log # } # # EXAMPLE RULE FOR SUSPICIOUS RULETYPE: # suspicious $HOME_NET any -> $HOME_NET 6667 (msg:"Internal IRC Server";) # # This example will create a rule type that will log to syslog # and a mysql database. # ruletype redalert # { # type alert # output alert_syslog: LOG_AUTH LOG_ALERT # output database: log, mysql, user=snort dbname=snort host=localhost # } # # EXAMPLE RULE FOR REDALERT RULETYPE # redalert tcp $HOME_NET any -> $EXTERNAL_NET 31337 \ # (msg:"Someone is being LEET"; flags:A+;) # # Include classification & priority settings # include ../share/snort/classification.config # # Include reference systems # include ../share/snort/reference.config #################################################################### # Step #4: Customize your rule set # # Up to date snort rules are available at http://www.snort.org # # The snort web site has documentation about how to write your own # custom snort rules. # # The rules included with this distribution generate alerts based on # on suspicious activity. Depending on your network environment, your # security policies, and what you consider to be suspicious, some of # these rules may either generate false positives ore may be detecting # activity you consider to be acceptable; therefore, you are # encouraged to comment out rules that are not applicable in your # environment. # # Note that using all of the rules at the same time may lead to # serious packet loss on slower machines. YMMV, use with caution, # standard disclaimers apply. :) # # The following individuals contributed many of rules in this # distribution. # # Credits: # Ron Gula <rgula@securitywizards.com> of Network Security Wizards # Max Vision <vision@whitehats.com> # Martin Markgraf <martin@mail.du.gtn.com> # Fyodor Yarochkin <fygrave@tigerteam.net> # Nick Rogness <nick@rapidnet.com> # Jim Forster <jforster@rapidnet.com> # Scott McIntyre <scott@whoi.edu> # Tom Vandepoel <Tom.Vandepoel@ubizen.com> # Brian Caswell <bmc@snort.org> # Zeno <admin@cgisecurity.com> # Ryan Russell <ryan@securityfocus.com> # #========================================= # Include all relevant rulesets here # # shellcode, policy, info, backdoor, and virus rulesets are # disabled by default. These require tuning and maintance. # Please read the included specific file for more information. #========================================= include $RULE_PATH/bad-traffic.rules include $RULE_PATH/exploit.rules include $RULE_PATH/scan.rules include $RULE_PATH/finger.rules include $RULE_PATH/ftp.rules include $RULE_PATH/telnet.rules include $RULE_PATH/rpc.rules include $RULE_PATH/rservices.rules include $RULE_PATH/dos.rules include $RULE_PATH/ddos.rules include $RULE_PATH/dns.rules include $RULE_PATH/tftp.rules include $RULE_PATH/web-cgi.rules include $RULE_PATH/web-coldfusion.rules include $RULE_PATH/web-iis.rules include $RULE_PATH/web-frontpage.rules include $RULE_PATH/web-misc.rules include $RULE_PATH/web-client.rules include $RULE_PATH/web-php.rules include $RULE_PATH/sql.rules include $RULE_PATH/x11.rules include $RULE_PATH/icmp.rules include $RULE_PATH/netbios.rules include $RULE_PATH/misc.rules include $RULE_PATH/attack-responses.rules include $RULE_PATH/oracle.rules include $RULE_PATH/mysql.rules include $RULE_PATH/snmp.rules include $RULE_PATH/smtp.rules include $RULE_PATH/imap.rules include $RULE_PATH/pop2.rules include $RULE_PATH/pop3.rules include $RULE_PATH/nntp.rules include $RULE_PATH/other-ids.rules # include $RULE_PATH/web-attacks.rules # include $RULE_PATH/backdoor.rules # include $RULE_PATH/shellcode.rules # include $RULE_PATH/policy.rules # include $RULE_PATH/porn.rules # include $RULE_PATH/info.rules # include $RULE_PATH/icmp-info.rules # include $RULE_PATH/virus.rules # include $RULE_PATH/chat.rules # include $RULE_PATH/multimedia.rules # include $RULE_PATH/p2p.rules include $RULE_PATH/experimental.rules include $RULE_PATH/local.rules # end snort.conf -- Louis Kowolowski louisk@cryptomonkeys.org Crypto Monkeys: http://www.cryptomonkeys.org/~louisk IRC: outcast-consultants.biz#outcasts gpg info: http://www.cryptomonkeys.org/~louisk/gurgi.html gpg print: F04B 9A37 822A 4CE1 95CE 4D28 1AFF CCB7 DE4B A841 Everyone is a genius. It's just that some people are too stupid to realize it.
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