[Snort-users] base64 snort options

whliudunjun whliudunjun at ...7427...
Mon Jun 11 22:55:38 EDT 2012


should be like this:
 
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Suspicious outbound post"; flow:to_server,established; content:"POST"; http_method; content:"index.php"; http_uri;flow    bits:set,badpost;flowbits:noalert;sid:10000088;)
alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"base64 returned from outbound post";flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code;     content:"text/html"; base64_decode:relative; base64_data;  content:"webmail.vigilante.dk";sid:10000089;)
 
But still can't detecte the given pcap traffic,seems the base64 decode doesn't work?

At 2012-06-12 01:40:51,whliudunjun <whliudunjun at ...7427...> wrote:

hi,Joel Esler,
  sorry for that I'm not familiar with the snort signature,i read the snort_manual.pdf and read:3.6.10 flowbits
i use the signature you wrote ,it still didn't output any alert.
 
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Suspicious outbound post"; flow:to_server,established; content:"POST"; http_method; content:"index.php"; http_uri;flow    bits:set,badpost;flowbits:noalert;sid:10000088;)
 
alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; base64_decode:relative; base64_data;  content:"webmail.vigilante.dk";sid:10000089;)
 
Thanks and best regards.


At 2012-06-11 20:32:00,"Joel Esler" <jesler at ...1935...> wrote:
><have not looked at pcap>
>
>You have to use both sigs I gave you below.
>
>
>On Jun 10, 2012, at 11:53 PM, whliudunjun wrote:
>
>> 
>> Hi,Joel Esler,
>> Thanks for your quickly reply,here i will post my pcap :f43b7121dadb17ff057bfdbba9b0c18f.pcap and the snort -T output if that you can know what's my trouble,i still cant use any sig detected the said traffic,when i use:
>> ----------------------------------------------------------------------------------------------------------------------------------------------------------
>> alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; http_header; base64_decode:relative; base64_data;  content:"webmail.vigilante.dk"; sid:10000043;rev:1;).
>> ----------------------------------------------------------------------------------------------------------------------------------------------------------
>> snort -A fast -b -d -r f43b7121dadb17ff057bfdbba9b0c18f.pcap  -c /opt/snort/etc/test.conf
>>  
>> nothing alert log.
>>  
>> Thanks.
>> 
>> At 2012-06-09 03:44:38,"Joel Esler" <jesler at ...1935...> wrote:
>> >alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Suspicious outbound post"; flow:to_server,established; content:"POST"; http_method; content:"index.php"; http_uri; flowbits:set,badpost; flowbits:noalert; sid:1;)
>> >
>> >alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; base64_decode:relative; base64_data;  content:"webmail.vigilante.dk"; sid:2;)
>> >
>> >or
>> >
>> >alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; base64_decode:relative; base64_data;  content:"varchar("; content:"cast("; distance:0; sid:3;)
>> >
>> >Actually the below won't work, the above should.
>> >
>> >
>> >On Jun 8, 2012, at 3:43 PM, Joel Esler wrote:
>> >
>> >> Maybe something like this:
>> >> 
>> >> alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"Suspicious outbound post"; flow:to_server,established; content:"POST"; http_method; content:"index.php"; http_uri; flowbits:set,badpost; flowbits:noalert; sid:1;)
>> >> 
>> >> alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; http_header; base64_decode:relative; base64_data;  content:"webmail.vigilante.dk"; sid:2;)
>> >> 
>> >> or
>> >> 
>> >> alert tcp $EXTERNAL_NET $HTTP_PORTS -> $EXTERNAL_NET $HTTP_PORTS (msg:"base64 returned from outbound post"; flow:to_client,established; flowbits:isset,badpost; content:"200"; http_stat_code; content:"text/html"; http_header; base64_decode:relative; base64_data;  content:"varchar("; content:"cast("; distance:0; sid:3;)
>> >> 
>> >> 
>> >> 
>> >> 
>> >> Note, I wrote those off the top of my head.  I didn't test them as I don't have a pcap of the traffic.
>> >> 
>> >> --
>> >> Joel Esler
>> >> Senior Research Engineer, VRT
>> >> OpenSource Community Manager
>> >> Sourcefire
>> >> 
>> >> 
>> >> On Jun 8, 2012, at 2:05 AM, whliudunjun wrote:
>> >> 
>> >>> when i use snort to scan pcap package,the net traffic like following:
>> >>> 
>> >>> the traffic:---------------------------------------------------------------------------------------
>> >>> send:
>> >>> POST /metcon/index.php?id=73EEFFDBC2080030429BE52FA2866576 HTTP/1.1
>> >>> Content-Type: application/x-www-form-urlencoded
>> >>> User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Axo 9.104.044 )
>> >>> Host: 178.157.202.31
>> >>> Content-Length: 4
>> >>> Cache-Control: no-cache
>> >>> INIT
>> >>> receive:
>> >>> HTTP/1.1 200 OK
>> >>> Date: Wed, 06 Jun 2012 09:58:00 GMT
>> >>> Server: Apache
>> >>> Vary: Accept-Encoding
>> >>> Content-Length: 2196
>> >>> Content-Type: text/html
>> >>> d2VibWFpbC52aWdpbGFudGUuZGs=#ODA=#MDAwMA==#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#X19fXw==#TW96aWxsYS81LjAgKFdpbmRvd3MgTlQgNS4xKSBBcHBsZVdlYktpdC81MzUuMTkgKEtIVE1MLCBsaWtlIEdlY2tvKSBDaHJvbWUvMTguMC4xMDI1LjE2MiBTYWZhcmkvNTM1LjE5##fDgxMw==#
>> >>> 
>> >>> end-------------------------------------------------------------------------------------------------------------------------------------------------------
>> >>> 
>> >>> base64:
>> >>> d2VibWFpbC52aWdpbGFudGUuZGs=#
>> >>> ascii:webmail.vigilante.dk
>> >>> 
>> >>> the receive data is encode using base64,so i write a snort rules to detected it:
>> >>> 41 alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"Trojan SQL injection code receive"; flow:to_client,established;content:"HTTP/1.1 200 OK";content:"webmail.vigilante.dk";clas    stype:trojan-activity; sid:10000043; rev:1;)
>> >>> 
>> >>> why this sig can't detect above traffic,is there anyone can tell me why?or i write rules at a wrong way,or i need to open some config option.
>> >>> 
>> >>> 
>> >>> 
>> >>> 
>> >>> 
>> >>> ------------------------------------------------------------------------------
>> >>> Live Security Virtual Conference
>> >>> Exclusive live event will cover all the ways today's security and 
>> >>> threat landscape has changed and how IT managers can respond. Discussions 
>> >>> will include endpoint security, mobile security and the latest in malware 
>> >>> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/_______________________________________________
>> >>> Snort-users mailing list
>> >>> Snort-users at lists.sourceforge.net
>> >>> Go to this URL to change user options or unsubscribe:
>> >>> https://lists.sourceforge.net/lists/listinfo/snort-users
>> >>> Snort-users list archive:
>> >>> http://www.geocrawler.com/redir-sf.php3?list=snort-users
>> >>> 
>> >>> Please visit http://blog.snort.org to stay current on all the latest Snort news!
>> >> 
>> >
>> 
>> 
>> 
>> <pcap.zip>
>



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.snort.org/pipermail/snort-users/attachments/20120612/cb553854/attachment.html>


More information about the Snort-users mailing list