[Snort-users] Snort and SQL performance

Kevin Brown Kevin.M.Brown at ...1022...
Thu Sep 6 10:34:02 EDT 2001


Well, I tried running a query of the MySQL database to retrieve some
information for a report.  The query is basically what the ACID main page
looks like, but with a date restriction having been added to just show the
number and type of alerts for the previous month.  In Postgres this query
took, maybe, half an hour to complete, but with MySQL it was at 1400
mintutes and counting on just the first of 4 querys.  I asked for assistance
from the SQL guru here at work to see if there was a way to improve the
performance of the query, but no luck.

"SELECT count(*) FROM tcphdr INNER JOIN event ON event.cid = tcphdr.cid
WHERE MONTH(event.timestamp) = '$month'";
"SELECT count(*) FROM udphdr INNER JOIN event ON event.cid = udphdr.cid
WHERE MONTH(event.timestamp) = '$month'";
"SELECT count(*) FROM icmphdr INNER JOIN event ON event.cid = icmphdr.cid
WHERE MONTH(event.timestamp) = '$month'";
"SELECT count(*) FROM event INNER JOIN signature ON signature.sig_id =
event.signature WHERE signature.sig_name LIKE 'spp_portscan%' AND
MONTH(event.timestamp) = '$month'";

$month is set by calling the linux date command and then subtracting 1 to
find out lasts months number.

> -----Original Message-----
> From: Fraser Hugh [mailto:hugh_fraser at ...2804...]
> Sent: Wednesday, September 05, 2001 12:13
> To: 'Kevin Brown'; 'snort-users at lists.sourceforge.net'
> Subject: RE: [Snort-users] Snort and SQL performance
> 
> 
> Postgres's transaction overhead seems to make a considerable 
> difference to
> ACID, which issues a lot of queries building its pages. The 
> DB itself isn't
> slow... I've written some perl scripts to generate stats that 
> quickly churn
> through endless Code Red alerts, but they're based upon 
> queries written to
> use the DB efficiently, something that's more difficult to do 
> from a generic
> user query web page. Even with fsync turned off, deleting 
> 40000 Code Red
> alerts through ACID is painful, but very quick in Perl. I suspect some
> optimization in ACID would bring Postgres and MySQL closer  
> in performance.
> 
> In my environment, I wanted to merge Snort and ACID with DCL 
> (a free trouble
> ticket tracking system) to manage the audit trail that we 
> generate when
> there's a security alert. A bit of plpgsql to add some 
> triggers to the snort
> database , a couple of tables to identify alerts we're interested in
> tracking, and I've extended Snort to cut trouble tickets in 
> DCL without
> actually changing Snort or any rules. Eventually, I'll get around to a
> custom output plugin, but triggers in Postgres seemed much simpler. My
> solution for the performance issue has been to use scheduled 
> perl scripts to
> do daily pruning of old events to keep the size down.
> 
> > -----Original Message-----
> > From:	Kevin Brown [SMTP:Kevin.M.Brown at ...1022...]
> > Sent:	Wednesday, September 05, 2001 1:01 PM
> > To:	'snort-users at lists.sourceforge.net'
> > Subject:	[Snort-users] Snort and SQL performance
> > 
> > Currently running Version 1.8.1-RELEASE (Build 74) on a 
> Netra T1 AC200
> > (500MHz Sparc IIe, 1GB RAM, 2x 18GB 10k RPM SCSI drives) and have it
> > logging
> > to a remote SQL database, MySQL 3.23.40 running on a Quad 
> PII450 Xeon, 2GB
> > RAM, 40GB Hard drive space devoted to the database.  I have 
> noticed that
> > as
> > the database gets larger in size, the performance of snort 
> begins to slip.
> > During the summer when few to no students were present, 
> snort was clocking
> > along at 70% of the CPU.  The semester has begun and 
> network usage has
> > risen, yet snort has slowly gone down from 70% to 45%.  The 
> only thing
> > that
> > has changed on the network is that the SQL Database has grown from 0
> > records
> > on 8-13-01 to 2,632,460 records as of an hour and a half 
> ago, listening on
> > a
> > total of 200Mb of bandwidth to various ISPs that service 
> this campus.  I
> > have also tried this with PostgreSQL, but while the insert 
> performance may
> > have been better the ACID performance for viewing the data 
> was an order of
> > magnitude, or more, worse (e.g. 100s for postgres vs. 10s 
> for mysql).
> > 
> > To me this suggests that there may still be some tuning 
> options, either in
> > mysql or in the spo_database plugin to improve the speed of 
> the inserts to
> > see if that keeps snort chugging along happily.
> > 
> > END OF LINE...
> > 
> > Begin Geek Code;
> > 
> $_='while(read+STDIN,$_,2048){$a=29;$b=73;$c=142;$t=255;@t=map
> {$_%16or$t^=
> > $c
> > ^=(
> > 
> $m=(11,10,116,100,11,122,20,100)[$_/16%8])&110;$t^=(72, at z=(64,
> 72,$a^=12*($
> > _%
> > 16
> > 
> -2?0:$m&17)),$b^=$_%64?12:0, at z)[$_%8]}(16..271);if((@a=unx"C*"
> ,$_)[20]&48)
> > {$
> > h
> > 
> =5;$_=unxb24,join"", at b=map{xB8,unxb8,chr($_^$a[--$h+84])}@ARGV
> ;s/...$/1$&/
> > ;$
> > 
> d=unxV,xb25,$_;$e=256|(ord$b[4])<<9|ord$b[3];$d=$d>>8^($f=$t&(
> $d>>12^$d>>4
> > ^
> > 
> $d^$d/8))<<17,$e=$e>>8^($t&($g=($q=$e>>14&7^$e)^$q*8^$q<<6))<<
> 9,$_=$t[$_]^
> > 
> (($h>>=8)+=$f+(~$g&$t))for at ...1981...[128..$#a]}print+x"C*", at a}';s/x/pa
> ck+/g;eval
> > 
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