Re: Problems with multipleconfigs.

[Bhagya Bantwal <bbantwal () sourcefire com>]

On Fri, Mar 11, 2011 at 1:48 PM, carlopmart <carlopmart () gmail com> wrote:

> On 03/11/2011 07:34 PM, Bhagya Bantwal wrote:
> > On Fri, Mar 11, 2011 at 12:34 PM, carlopmart <carlopmart () gmail com
> > <mailto:carlopmart () gmail com>> wrote:
> >
> >     On 03/11/2011 06:13 PM, Bhagya Bantwal wrote:
> >      > Http Inspect needs to be enabled when using http content
> >     modifiers such
> >      > as http_method, http_header, http_uri etc. It looks like you have
> >     rules
> >      > with http content modifiers in your all.rules.
> >      >
> >      > You dont have to turn them on in all configs. Just turn them on
> >     in the
> >      > config which includes the rule with http modifiers (In your case
> the
> >      > config which includes all.rules).
> >      >
> >      > Without http inspect the HTTP headers, uri etc are not be
> >     extracted and
> >      > hence the error.
> >      >
> >      > -B
> >      >
> >
> >     Thanks Bhagya for your response. I have turn on only on the secondary
> >     snort configuration, but if doesn't exists an entry about http
> instpect
> >     on snort.conf, snort doesn't starts. I have not activated any rule in
> >     the main configuration file. Only on the secondaries config files.
> >
> >
> > What is your http config?
> >
> > If you are using the http config variables such as compress_depth  and
> > decompress_depth you need to specify these in your base conf (
> > snort.conf in your case).
> >
> > -B
>
> This is my snort.conf (principal configuration file):
>
> ###################################################
> # Step #1: Configuration definition for all IDS sensors.
> ###################################################
>
> config binding: /data/config/etc/snort-prod/prod_ids.conf net
> 172.25.50.0/27
> config binding: /data/config/etc/snort-mgmt/mgmt_ids.conf net
> 172.17.47.16/28
>
> var LIB_PATH /usr/lib
> var COMMON_CONF_PATH /data/config/etc/snort-common
>
>
> ###################################################
> # Step #2: Configure the decoder.  For more information, see README.decode
> ###################################################
>
> 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 enable_decode_oversized_alerts
> # config enable_decode_oversized_drops
> config checksum_mode: all
> # config flowbits_size: 64
> # config ignore_ports: tcp 21 6667:6671 1356
> # config ignore_ports: udp 1:17 53
> # config response: eth0 attempts 2
>
>
> ###################################################
> # Step #3: Configure the base detection engine.  For more information,
> see  README.decode
> ###################################################
>
> 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
>
>
> ###################################################
> # Step #4: Configure dynamic loaded libraries.
> # For more information, see Snort Manual, Configuring Snort - Dynamic
> Modules
> ###################################################
>
> dynamicpreprocessor directory $LIB_PATH/snort_dynamicpreprocessor
> dynamicengine $LIB_PATH/snort_dynamicengine/libsf_engine.so
> dynamicdetection directory $LIB_PATH/snort_dynamicrules
>
>
> ###################################################
> # Step #5: Configure preprocessors
> # For more information, see the Snort Manual, Configuring Snort -
> Preprocessors
> ###################################################
>
> #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: max_tcp 8192, track_tcp yes, track_udp yes,
> track_icmp no 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 2100 3306 6070 6665 6666
> 6667 6668 6669 \
>         7000 32770 32771 32772 32773 32774 32775 32776 32777 32778 32779, \
>     ports both 80 311 443 465 563 591 593 636 901 989 992 993 994 995
> 1220 1414 1830 2301 2381 2809 3128 3702 5250 6907 7001 7702 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 8028 8080 8088 8118 8123 8180
> 8243 8280 8888 9090 9091 9443 9999 11371
> preprocessor stream5_udp: timeout 180
> 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
> preprocessor bo
> preprocessor ftp_telnet: global inspection_type stateful
> encrypted_traffic no
> 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
> preprocessor smtp: ports { 25 465 587 691 } \
>     inspection_type stateful \
>     enable_mime_decoding \
>     max_mime_depth 20480 \
>     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 }
> 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
> 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
> preprocessor dns: ports { 53 } enable_rdata_overflow
> preprocessor ssl: ports { 443 465 563 636 989 992 993 994 995 7801 7702
> 7900 7901 7902 7903 7904 7905 7906 6907 7908 7909 7910 7911 7912 7913
> 7914 7915 7916 7917 7918 7919 7920 }, trustservers, noinspec
> t_encrypted
> preprocessor sensitive_data: alert_threshold 25
> preprocessor sfportscan: proto { all } memcap { 10000000 } sense_level {
> high } scan_type { all } logfile { scans.log }
>
> And one of the my secondaries config files:
>
> ###################################################
> # Step #1: Set the network variables.  For more information, see
> README.variables
> ###################################################
>
> ipvar HOME_NET 172.25.50.0/27
> ipvar EXTERNAL_NET !$HOME_NET
> ipvar DNS_SERVERS 172.25.50.10
> ipvar SMTP_SERVERS 172.25.50.22
> ipvar HTTP_SERVERS 172.25.50.20
> ipvar SQL_SERVERS $HOME_NET
> ipvar TELNET_SERVERS $HOME_NET
> ipvar SSH_SERVERS $HOME_NET
> portvar HTTP_PORTS
>
> [80,311,591,593,901,1220,1414,1830,2301,2381,2809,3128,3702,5250,7001,7777,7779,8000,8008,8028,8080,8088,8118,8123,8180,8243,8280,8888,9090,9091,9443,9999,11371]
> portvar SHELLCODE_PORTS !80
> portvar ORACLE_PORTS 1024:
> portvar SSH_PORTS 22
> ipvar AIM_SERVERS
> [
> 64.12.24.0/23,64.12.28.0/23,64.12.161.0/24,64.12.163.0/24,64.12.200.0/24,205.188.3.0/24,205.188.5.0/24,205.188.7.0/24,205.188.9.0/24,205.188.153.0/24,205.188.179.0/24,205.188.248.0/24
> ]
>
> var LIB_PATH /usr/lib
> var CONF_PATH /data/config/etc/snort-prod
> var COMMON_CONF_PATH /data/config/etc/snort-common
> var RULE_PATH $COMMON_CONF_PATH/rules
> var SO_RULE_PATH $COMMON_CONF_PATH/so_rules
>
>
>
> ###################################################
> # Step #5: Configure preprocessors
> # For more information, see the Snort Manual, Configuring Snort -
> Preprocessors
> ###################################################
>
> preprocessor http_inspect: global iis_unicode_map
> $COMMON_CONF_PATH/unicode.map 1252 compress_depth 20480 decompress_depth

20480
>


As mentioned in my earlier email, you have compress and decompress depths
set in your secondary confs. This requires the http inspect config to be
enabled in the primary or base conf.

All you need to do is add

preprocessor http_inspect: global compress_depth 20480 decompress_depth
20480 disabled

in your primary conf. This does not enable http inspect in the primary
config. Refer to the snort manual for further details.

-B



> preprocessor http_inspect_server: server default \
>     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 \
>     ports { 80 311 591 593 901 1220 1414 1830 2301 2381 2809 3128 3702
> 5250 7001 7777 7779 8000 8008 8028 8080 8088 8118 8123 8180 8243 8280
> 8888 9090 9091 9443 9999 11371 } \
>     non_rfc_char { 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 } \
>     enable_cookie \
>     extended_response_inspection \
>     inspect_gzip \
>     normalize_utf \
>     unlimited_decompress \
>     apache_whitespace no \
>     ascii no \
>     bare_byte no \
>     base36 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
>
>
>
> ###################################################
> # Step #7: Customize your rule set
> # For more information, see Snort Manual, Writing Snort Rules
> #
> # NOTE: All categories are enabled in this conf file
> ###################################################
>
> ### include $RULE_PATH/local.rules
> include $RULE_PATH/all.rules
>
>
>
> --
> CL Martinez
> carlopmart {at} gmail {d0t} com
>
>
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