Snort mailing list archives

Re: snort black list issue

From: anton van der leun <anton () vanderleun com>
Date: Mon, 1 Aug 2016 22:45:04 +0200

Hi Hui,

Many thanks for reply.

"once per session" is new for me and does not ring a bell.



plse find below my preprocessor configuration:



= = = = = = = = = = = = = = = = = = = = = 

###################################################
# Step #5: Configure preprocessors
# For more information, see the Snort Manual, Configuring Snort - Preprocessors
###################################################

# GTP Control Channle Preprocessor. For more information, see README.GTP
# preprocessor gtp: ports { 2123 3386 2152 }

# Inline packet normalization. For more information, see README.normalize
# Does nothing in IDS mode
preprocessor normalize_ip4
preprocessor normalize_tcp: ips ecn stream
preprocessor normalize_icmp4
preprocessor normalize_ip6
preprocessor normalize_icmp6

# Target-based IP defragmentation.  For more inforation, see README.frag3
preprocessor frag3_global: max_frags 65536
preprocessor frag3_engine: policy windows detect_anomalies overlap_limit 10 min_fragment_length 100 timeout 180

# Target-Based stateful inspection/stream reassembly.  For more inforation, see README.stream5
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 81 311 383 443 465 563 591 593 636 901 989 992 993 994 995 1220 1414 1830 2301 2381 2809 3037 3128 
3702 4343 4848 5250 6988 7907 7000 7001 7144 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 8085 8088 8090 8118 8123 8180 8243 8280 8300 8800 8888 8899 9000 
9060 9080 9090 9091 9443 9999 11371 34443 34444 41080 50002 55555
preprocessor stream5_udp: timeout 180

# performance statistics.  For more information, see the Snort Manual, Configuring Snort - Preprocessors - Performance 
Monitor
# preprocessor perfmonitor: time 300 file /var/snort/snort.stats pktcnt 10000

# HTTP normalization and anomaly detection.  For more information, see README.http_inspect
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 81 311 383 591 593 901 1220 1414 1741 1830 2301 2381 2809 3037 3128 3702 4343 4848 5250 6988 7000 7001 
7144 7145 7510 7777 7779 8000 8008 8014 8028 8080 8085 8088 8090 8118 8123 8180 8181 8243 8280 8300 8800 8888 8899 9000 
9060 9080 9090 9091 9443 9999 11371 34443 34444 41080 50002 55555 } \
    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

# ONC-RPC normalization and anomaly detection.  For more information, see the Snort Manual, Configuring Snort - 
Preprocessors - RPC Decode
preprocessor rpc_decode: 111 32770 32771 32772 32773 32774 32775 32776 32777 32778 32779 no_alert_multiple_requests 
no_alert_large_fragments no_alert_incomplete

# Back Orifice detection.
preprocessor bo

# FTP / Telnet normalization and anomaly detection.  For more information, see README.ftptelnet
preprocessor ftp_telnet: global inspection_type stateful encrypted_traffic no check_encrypted
preprocessor ftp_telnet_protocol: telnet \
    ayt_attack_thresh 20 \
    normalize ports { 23 } \
    detect_anomalies
preprocessor ftp_telnet_protocol: ftp server default \
    def_max_param_len 100 \
    ports { 21 2100 3535 } \
    telnet_cmds yes \
    ignore_telnet_erase_cmds yes \
    ftp_cmds { ABOR ACCT ADAT ALLO APPE AUTH CCC CDUP } \
    ftp_cmds { CEL CLNT CMD CONF CWD DELE ENC EPRT } \
    ftp_cmds { EPSV ESTA ESTP FEAT HELP LANG LIST LPRT } \
    ftp_cmds { LPSV MACB MAIL MDTM MIC MKD MLSD MLST } \
    ftp_cmds { MODE NLST NOOP OPTS PASS PASV PBSZ PORT } \
    ftp_cmds { PROT PWD QUIT REIN REST RETR RMD RNFR } \
    ftp_cmds { RNTO SDUP SITE SIZE SMNT STAT STOR STOU } \
    ftp_cmds { STRU SYST TEST TYPE USER XCUP XCRC XCWD } \
    ftp_cmds { XMAS XMD5 XMKD XPWD XRCP XRMD XRSQ XSEM } \
    ftp_cmds { XSEN XSHA1 XSHA256 } \
    alt_max_param_len 0 { ABOR CCC CDUP ESTA FEAT LPSV NOOP PASV PWD QUIT REIN STOU SYST XCUP XPWD } \
    alt_max_param_len 200 { ALLO APPE CMD HELP NLST RETR RNFR STOR STOU XMKD } \
    alt_max_param_len 256 { CWD RNTO } \
    alt_max_param_len 400 { PORT } \
    alt_max_param_len 512 { SIZE } \
    chk_str_fmt { ACCT ADAT ALLO APPE AUTH CEL CLNT CMD } \
    chk_str_fmt { CONF CWD DELE ENC EPRT EPSV ESTP HELP } \
    chk_str_fmt { LANG LIST LPRT MACB MAIL MDTM MIC MKD } \
    chk_str_fmt { MLSD MLST MODE NLST OPTS PASS PBSZ PORT } \
    chk_str_fmt { PROT REST RETR RMD RNFR RNTO SDUP SITE } \
    chk_str_fmt { SIZE SMNT STAT STOR STRU TEST TYPE USER } \
    chk_str_fmt { XCRC XCWD XMAS XMD5 XMKD XRCP XRMD XRSQ } \
    chk_str_fmt { XSEM XSEN XSHA1 XSHA256 } \
    cmd_validity ALLO < int [ char R int ] > \   
    cmd_validity EPSV < [ { char 12 | char A char L char L } ] > \
    cmd_validity MACB < string > \
    cmd_validity MDTM < [ date nnnnnnnnnnnnnn[.n[n[n]]] ] string > \
    cmd_validity MODE < char ASBCZ > \
    cmd_validity PORT < host_port > \
    cmd_validity PROT < char CSEP > \
    cmd_validity STRU < char FRPO [ string ] > \   
    cmd_validity TYPE < { char AE [ char NTC ] | char I | char L [ number ] } >
preprocessor ftp_telnet_protocol: ftp client default \
    max_resp_len 256 \
    bounce yes \
    ignore_telnet_erase_cmds yes \
    telnet_cmds yes


# SMTP normalization and anomaly detection.  For more information, see README.SMTP
preprocessor smtp: ports { 25 465 587 691 } \
    inspection_type stateful \
    b64_decode_depth 0 \
    qp_decode_depth 0 \
    bitenc_decode_depth 0 \
    uu_decode_depth 0 \
    log_mailfrom \
    log_rcptto \
    log_filename \
    log_email_hdrs \
    normalize cmds \
    normalize_cmds { ATRN AUTH BDAT CHUNKING DATA DEBUG EHLO EMAL ESAM ESND ESOM ETRN EVFY } \
    normalize_cmds { EXPN HELO HELP IDENT MAIL NOOP ONEX QUEU QUIT RCPT RSET SAML SEND SOML } \
    normalize_cmds { STARTTLS TICK TIME TURN TURNME VERB VRFY X-ADAT X-DRCP X-ERCP X-EXCH50 } \
    normalize_cmds { X-EXPS X-LINK2STATE XADR XAUTH XCIR XEXCH50 XGEN XLICENSE XQUE XSTA XTRN XUSR } \
    max_command_line_len 512 \
    max_header_line_len 1000 \
    max_response_line_len 512 \
    alt_max_command_line_len 260 { MAIL } \
    alt_max_command_line_len 300 { RCPT } \
    alt_max_command_line_len 500 { HELP HELO ETRN EHLO } \
    alt_max_command_line_len 255 { EXPN VRFY ATRN SIZE BDAT DEBUG EMAL ESAM ESND ESOM EVFY IDENT NOOP RSET } \
    alt_max_command_line_len 246 { SEND SAML SOML AUTH TURN ETRN DATA RSET QUIT ONEX QUEU STARTTLS TICK TIME TURNME 
VERB X-EXPS X-LINK2STATE XADR XAUTH XCIR XEXCH50 XGEN XLICENSE XQUE XSTA XTRN XUSR } \
    valid_cmds { ATRN AUTH BDAT CHUNKING DATA DEBUG EHLO EMAL ESAM ESND ESOM ETRN EVFY } \
    valid_cmds { EXPN HELO HELP IDENT MAIL NOOP ONEX QUEU QUIT RCPT RSET SAML SEND SOML } \
    valid_cmds { STARTTLS TICK TIME TURN TURNME VERB VRFY X-ADAT X-DRCP X-ERCP X-EXCH50 } \
    valid_cmds { X-EXPS X-LINK2STATE XADR XAUTH XCIR XEXCH50 XGEN XLICENSE XQUE XSTA XTRN XUSR } \
    xlink2state { enabled }

# Portscan detection.  For more information, see README.sfportscan
# preprocessor sfportscan: proto  { all } memcap { 10000000 } sense_level { low }

# ARP spoof detection.  For more information, see the Snort Manual - Configuring Snort - Preprocessors - ARP Spoof 
Preprocessor
# preprocessor arpspoof
# preprocessor arpspoof_detect_host: 192.168.40.1 f0:0f:00:f0:0f:00

# SSH anomaly detection.  For more information, see README.ssh
preprocessor ssh: server_ports { 22 } \
                  autodetect \
                  max_client_bytes 19600 \
                  max_encrypted_packets 20 \
                  max_server_version_len 100 \
                  enable_respoverflow enable_ssh1crc32 \
                  enable_srvoverflow enable_protomismatch

# SMB / DCE-RPC normalization and anomaly detection.  For more information, see README.dcerpc2
preprocessor dcerpc2: memcap 102400, events [co ]
preprocessor dcerpc2_server: default, policy WinXP, \
    detect [smb [139,445], tcp 135, udp 135, rpc-over-http-server 593], \
    autodetect [tcp 1025:, udp 1025:, rpc-over-http-server 1025:], \
    smb_max_chain 3, smb_invalid_shares ["C$", "D$", "ADMIN$"]

# DNS anomaly detection.  For more information, see README.dns
preprocessor dns: ports { 53 } enable_rdata_overflow

# SSL anomaly detection and traffic bypass.  For more information, see README.ssl
preprocessor ssl: ports { 443 465 563 636 989 992 993 994 995 7801 7802 7900 7901 7902 7903 7904 7905 7906 7907 7908 
7909 7910 7911 7912 7913 7914 7915 7916 7917 7918 7919 7920 }, trustservers, noinspect_encrypted

# SDF sensitive data preprocessor.  For more information see README.sensitive_data
preprocessor sensitive_data: alert_threshold 25

# SIP Session Initiation Protocol preprocessor.  For more information see README.sip
preprocessor sip: max_sessions 40000, \
   ports { 5060 5061 5600 }, \
   methods { invite \
             cancel \
             ack \
             bye \
             register \
             options \
             refer \
             subscribe \
             update \
             join \
             info \
             message \
             notify \
             benotify \
             do \
             qauth \
             sprack \
             publish \
             service \
             unsubscribe \
             prack }, \
   max_uri_len 512, \
   max_call_id_len 80, \
   max_requestName_len 20, \
   max_from_len 256, \
   max_to_len 256, \
   max_via_len 1024, \
   max_contact_len 512, \
   max_content_len 2048

# IMAP preprocessor.  For more information see README.imap
preprocessor imap: \
   ports { 143 } \
   b64_decode_depth 0 \
   qp_decode_depth 0 \
   bitenc_decode_depth 0 \
   uu_decode_depth 0

# POP preprocessor. For more information see README.pop
preprocessor pop: \
   ports { 110 } \
   b64_decode_depth 0 \
   qp_decode_depth 0 \
   bitenc_decode_depth 0 \
   uu_decode_depth 0

# Modbus preprocessor. For more information see README.modbus
preprocessor modbus: ports { 502 }

# DNP3 preprocessor. For more information see README.dnp3
preprocessor dnp3: ports { 20000 } \
   memcap 262144 \
   check_crc

# Reputation preprocessor. For more information see README.reputation
preprocessor reputation: \
   memcap 500, \
   scan_local, \
   priority whitelist, \
   nested_ip inner, \
   whitelist /etc/snort/rules/white_list.rules, \
   blacklist /etc/snort/rules/black_list.rules, \
   blacklist /etc/snort/rules/black_list_local.rules, \
   white trust

##preprocessor appid : app_stats_filename appstats-unified.log, app_stats_period 60, app_detector_dir 
/usr/local/lib/openappid
##preprocessor appid: app_stats_filename appstats-u2.log, \
##   app_stats_period 60, \
##   app_detector_dir /usr/local/lib/openappid

= = = = = = = = = = = = = = = = = = = = =

-----Oorspronkelijk bericht-----
Afzender: Hui Cao (huica) <huica () cisco com>
Verstuurd: Maandag 1 Augustus 2016 21:16
Aan: anton van der leun <anton () vanderleun com>; snort-users () lists sourceforge net
Cc: anton () triple-t-services nl; alex () triple-t-services nl
Onderwerp: Re: [Snort-users] snort black list issue

Have you enabled session preprocessor?

Reputation preprocessor has been moved after session preprocessor. It is called once per session.

Best,
Hui.

From: anton van der leun <anton () vanderleun com <mailto:anton () vanderleun com> >
Date: Monday, August 1, 2016 at 6:08 AM
To: "snort-users () lists sourceforge net <mailto:snort-users () lists sourceforge net> " <snort-users () lists 
sourceforge net <mailto:snort-users () lists sourceforge net> >
Cc: "anton () triple-t-services nl <mailto:anton () triple-t-services nl> " <anton () triple-t-services nl 
<mailto:anton () triple-t-services nl> >, "alex () triple-t-services nl <mailto:alex () triple-t-services nl> " <alex 
() triple-t-services nl <mailto:alex () triple-t-services nl> >
Subject: [Snort-users] snort black list issue

Hello snort community

 
I ran into this issue while debugging a certain attack this weekend and noticed the following I don’t understand:

 
Conditions : snort blacklist has certain ip address

Results:  after adding this address and a warm reload of snort : ICMP messages are blocked, however tcp sessions are 
NOT.

 
Example (ip address is not yet added to black list)

 
root@xen2-zarafa-71-1:~# ping 5.157.87.137

PING 5.157.87.137 (5.157.87.137) 56(84) bytes of data.

64 bytes from 5.157.87.137: icmp_req=1 ttl=54 time=21.7 ms

64 bytes from 5.157.87.137: icmp_req=2 ttl=54 time=11.1 ms

^C

 
root@xen2-zarafa-71-1:~# telnet 5.157.87.137 80

Trying 5.157.87.137...

Connected to 5.157.87.137.

Escape character is '^]'.

^]

telnet> quit

Connection closed.

 
root@xen2-zarafa-71-1:~# ##snort blacklist added 5.157.87.137   and snort is reloaded

root@xen2-zarafa-71-1:~# ping 5.157.87.137     

PING 5.157.87.137 (5.157.87.137) 56(84) bytes of data.

^C

--- 5.157.87.137 ping statistics ---

5 packets transmitted, 0 received, 100% packet loss, time 4030ms

 
 
root@xen2-zarafa-71-1:~# telnet 5.157.87.137 80

Trying 5.157.87.137...

Connected to 5.157.87.137.

Escape character is '^]'.

^]

telnet> quit

Connection closed.

root@xen2-zarafa-71-1:~# 

 
The screenshot of my monitoring tool is included to show that the icmp message was indeed blocked

However a tcp sessiob to port 80 is still not blocked !

 
Here some config and version info:

 
[root@snort73 scripts]# /usr/local/bin/snort -V

 
   ,,_     -*> Snort! <*-

  o"  )~   Version 2.9.8.3 GRE (Build 383)

   ''''    By Martin Roesch & The Snort Team:http://www.snort.org/contact#team <http://www.snort.org/contact#team> 

           Copyright (C) 2014-2015 Cisco and/or its affiliates. All rights reserved.

           Copyright (C) 1998-2013 Sourcefire, Inc., et al.

           Using libpcap version 1.6.2

           Using PCRE version: 8.32 2012-11-30

           Using ZLIB version: 1.2.7

 
 
# Reputation preprocessor. For more information see README.reputation

preprocessor reputation: \

   memcap 500, \

   scan_local, \

   priority whitelist, \

   nested_ip inner, \

   whitelist /etc/snort/rules/white_list.rules, \

   blacklist /etc/snort/rules/black_list.rules, \

   blacklist /etc/snort/rules/black_list_local.rules, \

   white trust

 
 
In my opninion the reputation processor has absolute priority and all messages should be blocked.

I hope somebody can direct me in the right direction.

 
Thanks in advance,

Anton van der Leun

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Current thread:

snort black list issue anton van der leun (Aug 01)
- Re: snort black list issue Hui Cao (huica) (Aug 01)
- Message not available
  - Re: snort black list issue Hui cao (Aug 02)
- <Possible follow-ups>
- Re: snort black list issue anton van der leun (Aug 01)
- Re: snort black list issue anton van der leun (Aug 02)
  - Re: snort black list issue Hui cao (Aug 02)
- Re: snort black list issue anton van der leun (Aug 02)
- Re: snort black list issue anton van der leun (Aug 03)
- FW: snort black list issue anton van der leun (Aug 04)
- Re: snort black list issue anton van der leun (Aug 08)
  - Re: snort black list issue Hui cao (Aug 02)
    - Re: snort black list issue anton van der leun (Aug 02)
    - Re: snort black list issue anton van der leun (Aug 02)