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Re: buffer space



Hi David,

I too would like to know what version of SECSCAN you are using for the "required watches". I run the STIGS, SECSCAN, and a myriad of vulnerability analysis tools (outside looking in --> inside looking around) on systems that I ISSE and provision. I do not recall "required watches" that need to be set with this tool, but I maybe off a version and I may need to visit another sight to pick up the latest and greatest....

I know SECSCAN would like the System to be configured to HALT on audit failure using the disk_ful_action_setting in /etc/audit/auditd.conf. It would also like the system to be configured to halt on audit disk error as well as the audit data to be synchronously flushed to disk to avoid data loss. To do this (respectfully) I have set in my KickStarts and Satellite:

perl -npe 's/disk_full_action = SUSPEND/disk_full_action = HALT/' -i /etc/audit/auditd.conf perl -npe 's/disk_error_action = SUSPEND/disk_error_action = HALT/' -i /etc/audit/auditd.conf
perl -npe 's/flush = INCREMENTAL/flush = SYNC/' -i /etc/audit/auditd.conf

Currently I set the /var/log/audit logs to rotate daily for 90 days... in /etc/logrotate.d/audit and the capp.rules ; nispom.rules in /usr/share/doc/audit* all work great and provide nice examples to comply with Security Policy.

Because of the logrotation and the way aureport works, I have written a wrapper script to be able to search and report all the log files. Something of this type would help the Security Officers look threw the log files. The script also keeps a pristine copy of the log files for investigation with digital sigs to watch the tampering (as well as aide) for investigation if need be --> this keeps processing the files (MAC Times) and a pristine copy separated.

I am very interested in finding our more about these set watches that are required in SECSCAN.

Best regards,


Norman Mark St. Laurent
Conceras | Chief Technology Officer and ISSE



David Flatley wrote:

Thanks Steve!
If I were to move all the rotated logs to another directory, say /home/logs. So instead of doing "ausearch -i" to capture all the information in the rotated logs in /var/log/audit directory. I would do "ausearch -i -f /home/logs" , correct?

Backlog is set to 12288 right now.

The SECSCAN requires many -w (watches) and a fair amount of syscalls. I modified the syscalls to add your recommendation for using "arch=b32" and "arch=b64". Because I was getting errors restarting the auditd on some of their recommendations one of which was mount?

Another setting I believe was doing me in was the log size is 20 megs and I allow 8 rotated logs. But I had admin_disk_full set to 160 and the action was suspend.
So this could have been tripping me up also.

I would like to be able to do the audit log extractions (ausearch and aureport) when I get say 8 - 20 megs logs. I see I can do an exec on a script in max_log_file_action. So if I set the max_log_file to 160, I can then run a script to move the rotated logs and process them, thus not stopping auditd and keeping things working? I would set the max rotated logs to 10 to allow the new rotated log space then move the logs as you suggest.

Thanks.

David Flatley CISSP




Inactive hide details for Steve Grubb ---08/13/2009 02:29:34 PM---On Thursday 13 August 2009 10:56:50 am David Flatley wrote: > Steve Grubb ---08/13/2009 02:29:34 PM---On Thursday 13 August 2009 10:56:50 am David Flatley wrote: > Red Hat 5.3 running audit 1.7.7-6


From: 	
Steve Grubb <sgrubb redhat com>

To: 	
linux-audit redhat com

Cc: 	
David Flatley/Burlington/IBM IBMUS

Date: 	
08/13/2009 02:29 PM

Subject: 	
Re: buffer space




On Thursday 13 August 2009 10:56:50 am David Flatley wrote:
>   Red Hat 5.3 running audit 1.7.7-6
> Rotating logs at 20 megs and allowing 8 logs
> Rules have watches and syscalls from the SECSCAN recommendations, and have
> added some of Steve Grubb's recommendations.

I would be curious what the SECSCAN recommendations are. Never heard of it...


> When we extract and archive the audit logs we get "Error receiving audit
> netlink packet (No buffer space available) an "error sending signal info
> request"
> Our extract is: stop auditd then create a file and run ausearch -i > file
> then run an aureport -i > file then once that is done we delete all the
> logs and restart auditd.

I think this is your problem. If you have audit rules loaded and stop auditd,
then audit events are going to pile up in the queue waiting for auditd to
download them. At some point the kernel will decide auditd doesn't exist and
will dump all events to syslog. This probably is not what you want either.

I would recommend calling "service auditd rotate" and then grab logs
audit.log.1 -> audit.logs.7 and move them away to another directory for post processing the contents.

You may also want to check you backlog size settings too.


> If I run this manually it works fine but if I have it running it in a cron > we get Kernel panics, lockups and log data loss plus the buffer messages.

Shouldn't really make a difference.

-Steve


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