Re: Are these rules from community.rules redundant?

[Tyler Smith <tyler.smith () adventiumlabs com>]

Is this an error in community.rules, or is the redundancy intentional?

-Tyler

> On Jun 22, 2015, at 10:57 AM, Nick Randolph <drandolph () sourcefire com> wrote:
>
> 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; refere
> > nce: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 <ftp://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
> >
> >
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