Snort mailing list archives
Re: Are these rules from community.rules redundant?
From: Nick Randolph <drandolph () sourcefire com>
Date: Mon, 22 Jun 2015 11:57:52 -0400
Yes, in addition to sid:27628. On 06/22/2015 11:03 AM, Tyler Smith wrote:
I was doing an evaluation of the community.rules made available on the Snort web page <https://www.snort.org/downloads/#rule-downloads>, and noticed these two rules:|Rule @ line 2643: alert udp $HOME_NET any -> any 53 (msg:"BLACKLIST DNS request for known malware domain documents.myPicture.info"; flow:to_server; byte_test:1,!&,0xF8,2; content:"|09|documents|09|myPicture|04|info|00|"; fast_pattern:only; metadata:impact_flag red, policy balanced-ips drop, policy security-ips drop, ruleset community, service dns; reference:url,fireeye.com/blog/technical/2013/08/survival-of-the-fittest-new-york-times-attackers-evolve-quickly.html <http://fireeye.com/blog/technical/2013/08/survival-of-the-fittest-new-york-times-attackers-evolve-quickly.html>; classtype:trojan-activity; sid:27625; rev:2;) Rule @ line 2644: alert udp $HOME_NET any -> any 53 (msg:"BLACKLIST DNS request for known malware domain ftp.documents.myPicture.info"; flow:to_server; byte_test:1,!&,0xF8,2; content:"|03|ftp|09|documents|09|myPicture|04|info|00|"; fast_pattern:only; metadata:impact_flag red, policy balanced-ips drop, policy security-ips drop, ruleset community, service dns; reference:url,fireeye.com/blog/technical/2013/08/survival-of-the-fittest-new-york-times-attackers-evolve-quickly.html <http://fireeye.com/blog/technical/2013/08/survival-of-the-fittest-new-york-times-attackers-evolve-quickly.html>; classtype:trojan-activity; sid:27626; rev:2;) |Doesn't the |content| option in the first rule (||09|documents|09|myPicture|04|info|00||) make the 2nd rule redundant? That is, the 1st rule will always trigger if the 2nd rule does because its |content| option is a substring of the 2nd's |content| option (||03|ftp|09|documents|09|myPicture|04|info|00||)Thanks, Tyler ------------------------------------------------------------------------------ Monitor 25 network devices or servers for free with OpManager! OpManager is web-based network management software that monitors network devices and physical & virtual servers, alerts via email & sms for fault. Monitor 25 devices for free with no restriction. Download now http://ad.doubleclick.net/ddm/clk/292181274;119417398;o _______________________________________________ Snort-sigs mailing list Snort-sigs () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-sigs http://www.snort.org Please visit http://blog.snort.org for the latest news about Snort!
------------------------------------------------------------------------------ Monitor 25 network devices or servers for free with OpManager! OpManager is web-based network management software that monitors network devices and physical & virtual servers, alerts via email & sms for fault. Monitor 25 devices for free with no restriction. Download now http://ad.doubleclick.net/ddm/clk/292181274;119417398;o
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Current thread:
- Are these rules from community.rules redundant? Tyler Smith (Jun 22)
- Re: Are these rules from community.rules redundant? Nick Randolph (Jun 22)
- Re: Are these rules from community.rules redundant? Tyler Smith (Jun 22)
- Re: Are these rules from community.rules redundant? Patrick Mullen (Jun 23)
- Re: Are these rules from community.rules redundant? Tyler Smith (Jun 22)
- Re: Are these rules from community.rules redundant? Nick Randolph (Jun 22)