Bro Auxiliary Programs


Handy auxiliary programs related to the use of the Bro Network Security Monitor (


Installation is simple and standard:

make install


The “adtrace” utility is used to compute the network address that compose the internal and extern nets that bro is monitoring. This program just reads a pcap (tcpdump) file and writes out the src MAC, dst MAC, src IP, dst IP for each packet seen in the file.


The “bro-cut” utility reads ASCII Bro logs on standard input and outputs them to standard output with only the specified columns (the column names can be found in each log file in the “#fields” header line). The specified order of the column names determines the output order of the columns (i.e., “bro-cut” can reorder the columns). If no column names are specified, then “bro-cut” simply outputs all columns.

There are several command-line options available to modify the output (run “bro-cut -h” to see a list of all options). For example, there are options to convert timestamps into human-readable format, and options to specify whether or not to include the format header lines in the output (by default, they’re not included). For example, the following command will output the three specified columns from conn.log with the timestamps from the “ts” column being converted to human-readable format:

cat conn.log | bro-cut -d ts id.orig_h id.orig_p

The “bro-cut” utility can read the concatenation of one or more uncompressed ASCII log files produced by Bro version 2.0 or newer, as long as each log file contains format header lines (i.e., lines at the beginning of the file starting with “#”). So, for example, “bro-cut” cannot read a Bro log file in the JSON format. To read a compressed log file, a tool such as “zcat” must be used to uncompress the file. For example, “bro-cut” can read a group of compressed conn.log files with a command like this:

zcat conn.*.log.gz | bro-cut


A set of scripts used commonly for Bro development. Note that none of these scripts are installed by ‘make install’.

Extracts a connection from a trace file based on its UID found in Bro’s conn.log
Generates list of Mozilla SSL root certificates in a format readable by Bro.
A script to maintain the CHANGES and VERSION files.
Show commits to the fastpath branch not yet merged into master.
Run a number of Bro benchmarks on a trace file.


The “rst” utility can be invoked by a Bro script to terminate an established TCP connection by forging RST tear-down packets.

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Copyright 2016, The Bro Project. Last updated on February 25, 2017. Created using Sphinx 1.4.8.