Snort mailing list archives
Re: Simple IPS config for snort
From: kay <kay.diam () gmail com>
Date: Fri, 6 Jul 2012 10:43:23 +0400
My investigation gave some result. I've configured snort to dump all alert data. When I use INPUT table with NFQUEUE, snort dumps whole packet content. When I use PREROUTING table with NFQUEUE, snort dumps only TCP headers. Is that normal? 2012/7/5 kay <kay.diam () gmail com>:
Finally I've figured out what was wrong. I used PREROUTING table instead of INPUT. For some reason "content" rules doesn't work for PREROUTING table. Why? My task is to detect bad traffic and DNAT it to another server. Is it possible? 2012/7/5 kay <kay.diam () gmail com>:P.S. Simple trafic drop rule works perfect, ie: drop tcp any any -> any 80 (msg:"tcp packet dropped"; sid:123456789) But when I try to use "content" option it doesn't work even on simple rule when I try to connect to FTP server: drop tcp any any -> any 21 (content: "user root"; msg: "FTP root login"; sid:9573;) drop tcp any any -> any 21 (content: "USER root"; msg: "FTP root login"; sid:9574;) I also modified iptables rule to allow snort listen all ports: iptables -t nat -A PREROUTING -p tcp -j NFQUEUE --queue-num 1 2012/7/4 Joel Esler <jesler () sourcefire com>:I'm not sure what "snort-inline-plain" is. Snort is inherently an inline IPS when invoked with the -Q command line parameter and depending on the DAQ set up used to accept the packets. If Snort is NOT running, do the packets get through? -- Joel Esler Senior Research Engineer, VRT OpenSource Community Manager Sourcefire On Jul 4, 2012, at 10:37 AM, kay <kay.diam () gmail com> wrote:I've just compiled snort-inline:snort-inline-plain -V ,,_ -*> Snort! <*- o" )~ Version 2.9.2.3 IPv6 GRE (Build 205) '''' By Martin Roesch & The Snort Team: http://www.snort.org/snort/snort-team Copyright (C) 1998-2012 Sourcefire, Inc., et al. Using libpcap version 1.0.0 Using PCRE version: 7.8 2008-09-05 Using ZLIB version: 1.2.3snort-inline-plain --daq-list Available DAQ modules: pcap(v3): readback live multi unpriv nfq(v6): live inline multi dump(v1): readback live inline multi unpriv afpacket(v4): live inline multi unprivAnd trying to block something to test. I wrote the following rule: drop tcp any any -> any 80 (msg:"ROOTtest"; content:"USERroot"; nocase; sid:123123;) Then send the following packet to IPS server:echo "USERroot" | netcat ipstest 80 wget "http://ipstest/USERroot"Snort detects it and that's all... It should block, but it doesn't:Allow: 15 (100.000%)Here is the command I run: snort-inline-plain -vv -Q --daq nfq --daq-var queue=1 -c /etc/snort/snort.conf -A full Here is the iptables-save: iptables-save # Generated by iptables-save v1.4.7 on Wed Jul 4 18:31:43 2012 *filter :INPUT ACCEPT [23450:9358484] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [12016:2551103] COMMIT # Completed on Wed Jul 4 18:31:43 2012 # Generated by iptables-save v1.4.7 on Wed Jul 4 18:31:43 2012 *nat :PREROUTING ACCEPT [2722:367273] :POSTROUTING ACCEPT [2:123] :OUTPUT ACCEPT [2:123] -A PREROUTING -p tcp -m tcp --dport 80 -j NFQUEUE --queue-num 1 COMMIT # Completed on Wed Jul 4 18:31:43 2012 Here is my config: ipvar HOME_NET any ipvar EXTERNAL_NET any ipvar HTTP_SERVERS $HOME_NET portvar HTTP_PORTS [80,8080] var RULE_PATH rules var SO_RULE_PATH so_rules var PREPROC_RULE_PATH preproc_rules config disable_decode_alerts config disable_tcpopt_experimental_alerts config disable_tcpopt_obsolete_alerts config disable_tcpopt_ttcp_alerts config disable_tcpopt_alerts config disable_ipopt_alerts config checksum_mode: all config pcre_match_limit: 3500 config pcre_match_limit_recursion: 1500 config detection: search-method ac-split search-optimize max-pattern-len 20 config event_queue: max_queue 8 log 3 order_events content_length config paf_max: 16000 dynamicpreprocessor directory /usr/lib64/snort-2.9.2.3_dynamicpreprocessor dynamicengine /usr/lib64/snort-2.9.2.3_dynamicengine/libsf_engine.so preprocessor normalize_ip4 preprocessor normalize_tcp: ips ecn stream preprocessor normalize_icmp4 preprocessor normalize_ip6 preprocessor normalize_icmp6 preprocessor frag3_global: max_frags 65536 preprocessor frag3_engine: policy windows detect_anomalies overlap_limit 10 min_fragment_length 100 timeout 180 preprocessor stream5_global: track_tcp yes, \ track_udp yes, \ track_icmp no, \ max_tcp 262144, \ max_udp 131072, \ max_active_responses 2, \ min_response_seconds 5 preprocessor stream5_tcp: policy windows, detect_anomalies, require_3whs 180, \ overlap_limit 10, small_segments 3 bytes 150, timeout 180, \ ports client 21 22 23 25 42 53 79 109 110 111 113 119 135 136 137 139 143 \ 161 445 513 514 587 593 691 1433 1521 1741 2100 3306 6070 6665 6666 6667 6668 6669 \ 7000 8181 32770 32771 32772 32773 32774 32775 32776 32777 32778 32779, \ ports both 80 81 311 443 465 563 591 593 636 901 989 992 993 994 995 1220 1414 1830 2301 2381 2809 3128 3702 4343 4848 5250 7907 7001 7145 7510 7802 7777 7779 \ 7801 7900 7901 7902 7903 7904 7905 7906 7908 7909 7910 7911 7912 7913 7914 7915 7916 \ 7917 7918 7919 7920 8000 8008 8014 8028 8080 8088 8090 8118 8123 8180 8243 8280 8800 8888 8899 9080 9090 9091 9443 9999 11371 55555 preprocessor stream5_udp: timeout 180 preprocessor http_inspect: global iis_unicode_map unicode.map 1252 compress_depth 65535 decompress_depth 65535 preprocessor http_inspect_server: server default \ http_methods { GET POST PUT SEARCH MKCOL COPY MOVE LOCK UNLOCK NOTIFY POLL BCOPY BDELETE BMOVE LINK UNLINK OPTIONS HEAD DELETE TRACE TRACK CONNECT SOURCE SUBSCRIBE UNSUBSCRIBE PROPFIND PROPPATCH BPROPFIND BPROPPATCH RPC_CONNECT PROXY_SUCCESS BITS_POST CCM_POST SMS_POST RPC_IN_DATA RPC_OUT_DATA RPC_ECHO_DATA } \ chunk_length 500000 \ server_flow_depth 0 \ client_flow_depth 0 \ post_depth 65495 \ oversize_dir_length 500 \ max_header_length 750 \ max_headers 100 \ max_spaces 200 \ small_chunk_length { 10 5 } \ ports { 80 } \ non_rfc_char { 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 } \ enable_cookie \ extended_response_inspection \ inspect_gzip \ normalize_utf \ unlimited_decompress \ normalize_javascript \ apache_whitespace no \ ascii no \ bare_byte no \ directory no \ double_decode no \ iis_backslash no \ iis_delimiter no \ iis_unicode no \ multi_slash no \ utf_8 no \ u_encode yes \ webroot no output alert_syslog: LOG_AUTH LOG_ALERT include classification.config include reference.config include $RULE_PATH/test.rules ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users Please visit http://blog.snort.org to stay current on all the latest Snort news!
------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users Please visit http://blog.snort.org to stay current on all the latest Snort news!
Current thread:
- Simple IPS config for snort kay (Jul 04)
- Re: Simple IPS config for snort Joel Esler (Jul 04)
- Re: Simple IPS config for snort kay (Jul 05)
- Re: Simple IPS config for snort kay (Jul 05)
- Re: Simple IPS config for snort kay (Jul 05)
- Re: Simple IPS config for snort kay (Jul 05)
- Re: Simple IPS config for snort Joel Esler (Jul 04)