[Bro] event suppression

Azoff, Justin S jazoff at illinois.edu
Tue Feb 16 06:56:18 PST 2016

port_scan_interval is not the suppression interval:

        ## Port scans detect that an attacking host appears to be
        ## scanning a single victim host on several ports.  This notice
        ## is generated when an attacking host attempts to connect to
        ## :bro:id:`Scan::port_scan_threshold`
        ## unique ports on a single host over the previous
        ## :bro:id:`Scan::port_scan_interval` time range.

    ## Failed connection attempts are tracked over this time interval for
    ## the port scan detection.  A higher interval will detect slower
    ## scanners, but may also yield more false positives.

If you want to change the suppression interval, use:

redef Notice::type_suppression_intervals += {
    [Scan::Port_Scan]           = 300sec,
    [Scan::Address_Scan]        = 300sec,

- Justin Azoff

> On Feb 16, 2016, at 9:50 AM, Martin Arlitt <martin.arlitt at ucalgary.ca> wrote:
> hi
> the event suppression in Bro does not appear to work the way I thought 
> it would. For example, in my notice.log file, the suppress_for value 
> always appears to be 3600. In misc/scan.bro (loaded in local.bro), 
> addr_scan_interval and port_scan_interval both are set to 5min by 
> default, yet still report 3600 in the suppress_for column of the log. Is 
> there something obvious that I am overlooking?
> thanks Martin
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