OPNsense Forum

Archive => 17.7 Legacy Series => Topic started by: bobbythomas on January 25, 2018, 03:39:44 pm

Title: Lots of Parsing errors in Surricata logs for snort_vrt rules
Post by: bobbythomas on January 25, 2018, 03:39:44 pm

Hi,

I am seeing a large number of parsing errors in the Surricata logs and most of these are related to the snort_vrt rules. It looks like Surricata is not able to parse snort rules, how can we fix this?

Code: [Select]

19/1/2018 -- 03:55:14 - <Error> - [ERRCODE: SC_ERR_INVALID_SIGNATURE(39)] - previous keyword has a fast_pattern:only; set. Can't have relative keywords around a fast_pattern only content
19/1/2018 -- 03:55:14 - <Error> - [ERRCODE: SC_ERR_INVALID_SIGNATURE(39)] - error parsing signature "drop  tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"MALWARE-OTHER Win.Trojan.Zeus Spam 2013 dated zip/exe HTTP Response - potential malware download"; flow:to_client,established; content:"-2013.zip|0D 0A|"; fast_pattern:only; content:"-2013.zip|0D 0A|"; http_header; content:"-"; within:1; distance:-14; http_header; file_data; content:"-2013.exe"; content:"-"; within:1; distance:-14; metadata:impact_flag red, policy balanced-ips drop, policy security-ips drop, ruleset community, service http; reference:url,www.virustotal.com/en/file/2eff3ee6ac7f5bf85e4ebcbe51974d0708cef666581ef1385c628233614b22c0/analysis/; classtype:trojan-activity; sid:26470; rev:1;)" from file /usr/local/etc/suricata/opnsense.rules/snort_vrt.malware-other.rules at line 44
19/1/2018 -- 03:55:16 - <Error> - [ERRCODE: SC_ERR_PCRE_PARSE(7)] - parse error, ret -1, string 1,=,0x05,6,relative,bitmask 0x14
19/1/2018 -- 03:55:16 - <Error> - [ERRCODE: SC_ERR_INVALID_SIGNATURE(39)] - error parsing signature "drop  tcp $EXTERNAL_NET any -> $HOME_NET 445 (msg:"SERVER-SAMBA Samba unsigned connections attempt"; flow:to_server, established; content:"|FF|SMB"; depth:4; offset:4; byte_test:1,=,0x05,6,relative,bitmask 0x14; content:"|00 00 00 00 00 00 00 00|"; within:8; distance:10; metadata:policy balanced-ips drop, policy max-detect-ips drop, policy security-ips drop; reference:cve,2017-12150; reference:url,samba.org/samba/security/CVE-2017-12150.html; classtype:attempted-user; sid:45074; rev:3;)" from file /usr/local/etc/suricata/opnsense.rules/snort_vrt.server-samba.rules at line 53
19/1/2018 -- 03:55:16 - <Error> - [ERRCODE: SC_ERR_INVALID_SIGNATURE(39)] - pcre with /R (relative) needs preceeding match in the same buffer
19/1/2018 -- 03:55:16 - <Error> - [ERRCODE: SC_ERR_INVALID_SIGNATURE(39)] - error parsing signature "alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (msg:"SERVER-WEBAPP Oracle GlassFish Server authentication bypass attempt"; flow:to_server,established; content:"GET"; nocase; http_method; content:"/applications/upload"; http_uri; pcre:"/^(Frame)?\.jsf/R"; content:!"JSESSIONID="; flowbits:set,glassfish_unauth_attempt; metadata:service http; reference:bugtraq,47438; reference:cve,2011-0807; classtype:attempted-admin; sid:20159; rev:8;)" from file /usr/local/etc/suricata/opnsense.rules/snort_vrt.server-webapp.rules at line 278
19/1/2018 -- 03:55:55 - <Notice> - rule reload complete

Thank you,
Regards,
Bobby Thomas

Title: Re: Lots of Parsing errors in Surricata logs for snort_vrt rules
Post by: franco on January 25, 2018, 03:41:03 pm

You can only fix this by using Snort, or disabling the offending rules.

Some rules are compatible, some are not. In general it's better to have the VRT rules rather than not having them.


Cheers,
Franco

Title: Re: Lots of Parsing errors in Surricata logs for snort_vrt rules
Post by: bobbythomas on January 25, 2018, 04:00:20 pm

Thank you Franco for the clarification. Yes, it's better to have something than nothing.

Regards,
Bobby Thomas