[Snort-users] ACID Alert Cache Empty

Kevin Brown Kevin.M.Brown at ...1022...
Wed Jul 24 11:37:03 EDT 2002


I still haven't found a solution for this.  I did go to cvs to see what the
difference between the 104 and 105 schemas are and the only thing that was
changed was the version number stuck into the database.  I have tried
downgrading software on the system to see if that fixes it (one program at a
time).  Still no success.  Backed down to ADODB 2.1.2, php 4.1.2, acid
.9.6b18.  The only thing I haven't reinstalled is MySQL, but I can't see a
reason why a minor version number change would cause this.

As a test I brought all the programs back up to date (ADODB 2.2.1, PHP
4.2.2, ACID .9.6b22), then went to an archive db that was logged to by an
older version of snort to schema 104 of the db (archive is from last
october).  Dropped the acid created tables, then using ACID rebuilt them and
loaded the page.  All the alerts were moved to the cache, so I'm left with
only one conclusion.  The problem must be with snort itself and the way it
is logging to the MySQL database that is causing the issue.  Currently have
Snort 1.9-dev build 167 running on the sensor.

-----Original Message-----
From: Kevin Brown
To: ''Snort-users ' '
Sent: 7/22/02 9:29 AM
Subject: RE: [Snort-users] ACID Alert Cache Empty

Well I still haven't been able to isolate the cause of this problem.
Near the end of last weeks archive ACID started moving some of the
alerts into the alert cache.  Unfortunately only 600,000 of the nearly
1.4 million alerts were moved to the cache.  This weeks current alerts
are again not being moved to the cache.  I don't know what broke it
other than possibly moving up to schema 105 of the database.

P.S.  Just went through the weekly archives and sure enough the cache
stopped pulling all the alerts up into it after moving to schema 105.
Only reason I did move up was because snort complained about schema 104.

-----Original Message----- 
From: Imran William Smith 
To: Kevin Brown 
Cc: 'Snort-users ' 
Sent: 7/21/02 4:49 PM 
Subject: Re: [Snort-users] ACID Alert Cache Empty 

IT's not a single function, it's about 5 inserts, 1 for TCP, 1 for UDP, 
etc. 
I think it's acid_cache.inc 
  
You'll still need to implement something similar to the below algorithm 
if you 
want it to run exactly how acid does it at the moment.  Or at least, 
make sure 
you do it sensor by sensor. 
  
I'd be grateful if you let me know what the cause was... 
  
Imran 
  
-- 
Imran William Smith 
Security Products Development 
Mimos Bhd, Malaysia 
  
  
  

----- Original Message ----- 
From: Kevin  < mailto:Kevin.M.Brown at ...1022...
<mailto:Kevin.M.Brown at ...1022...> > Brown 
To: 'Imran William Smith ' < mailto:iwsmith at ...487...
<mailto:iwsmith at ...487...> >  ; 'Kevin Brown 
< mailto:Kevin.M.Brown at ...1022... <mailto:Kevin.M.Brown at ...1022...> > ' 
Cc: 'Snort-users ' < mailto:Snort-users at lists.sourceforge.net
<mailto:Snort-users at lists.sourceforge.net> >  
Sent: Friday, July 19, 2002 11:23 PM 
Subject: RE: [Snort-users] ACID Alert Cache Empty 


Sorry, should have been more clear.  I dropped the ACID cache and event 
tables from the mysql command prompt (drop table <table name>), then 
went to the PHP frontend and it remade the tables from the script that 
came with ACID (create_acid_tbls_mysql.sql).  Still no data is being 
propogated from the event table (which has continued to grow) to the 
acid_event table.  I guess I'll try to find the function in ACID that 
updates the ACID cache tables and see if I can run it from the mysql 
prompt on the server. 

-----Original Message----- 
From: Imran William Smith 
To: Kevin Brown 
Cc: Snort-users 
Sent: 7/18/02 6:15 PM 
Subject: Re: [Snort-users] ACID Alert Cache Empty 

The algorithm acid uses is something like 
  
for each sensor 
    get highest sid in acid_event table     -> (call it 
acid_event_max_sid) 
  
    for all rows in event where event.sid > acid_event_max_sid 
        insert corresponding rows into acid_event 
    end for 
end for 
  
This all has to happen this way, because MySQL does not handle the 
where not exists (subquery) structure, which would mean the whole thing 
could 
be done in a single query. 
  
  
So my guess is some auto-increment problem is stopping the insert 
happening, 
Acid somehow thinks acid_event is already full.  You could try dropping 
and recreate the 
acid_event table.  That might probably solve it.  Because when you 
say 'rebuilding', I presume you mean 'rebuilding' in the frontend, 
rather than a 
drop ; create operation.  So you've totally reset the snort schema, but 
not the acid 
schema. 
  
  
  
-- 
Imran William Smith 
Security Products Development 
Mimos Bhd, Malaysia 
  
  
  

----- Original Message ----- 
From: Kevin  < mailto:Kevin.M.Brown at ...1022...
<mailto:Kevin.M.Brown at ...1022...>  
< mailto:Kevin.M.Brown at ...1022... <mailto:Kevin.M.Brown at ...1022...> > > Brown 
To: 'snort-users at lists.sourceforge.net' 
< mailto:'snort-users at lists.sourceforge.net'
<mailto:'snort-users at lists.sourceforge.net'>  
< mailto:'snort-users at lists.sourceforge.net'
<mailto:'snort-users at lists.sourceforge.net'> > >  
Sent: Friday, July 19, 2002 12:57 AM 
Subject: [Snort-users] ACID Alert Cache Empty 


An issue seems to have popped up this week with Snort (1.9-dev from CVS)


and ACID (0.9.6b22). 

MySQL Server setup: 
ACID 0.9.6b22 
MySQL 3.23.51 
Schema 105 
ADODB 2.12 

Last week worked fine.  Snort was logging to the MySQL server and ACID 
would properly update the cache with the new events.  This week it is 
properly logging to the db, but ACID won't update the cache of events. 

What happens (and this has been working for almost a year) is that on 
Sunday night the old database is moved to a new folder and a new snort 
database (completely empty) is put into place by rerunning the db schema


creation script (create_mysql). 

I have tried deleting the ACID cache tables and rebuilding them, but it 
still didn't update the chache with the now over 700,000 alerts.  I can 
go to the "Cache and Status" page and see that the database has has a 
large number of alerts, but it shows 0 for the cached events.  Hit 
update alert cache and it adds 0 alerts to the cache.  Repair tables 
doesn't seem to do anything, nor does Rebuild Alert Cache from the same 
page. 

No software has been changed while I was gone. 

Any other suggestions? 

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