Brute Force Detection
Put up a barrier between you and the bad guys with Brute Force Detection (BFD), published by Rfx Networks (www.rfxn .com/projects/brute-force-detection/). This free software tool helps defend against brute force hacking attacks on dedicated web servers.
Brute force attacks are characterized by their scattergun approach, such as using the entire dictionary as username and password inputs — methodically seeking the correct combination that will allow access to web server roots — or to paysite members areas.
BFD detects these multiple, malicious login attempts, blocking the hacker’s efforts.
According to R-fx Networks, BFD is a modular shell script for parsing application logs and checking for authentication failures.
“It does this using a rules system where application specific options are stored including regular expressions for each unique auth format,” the company website says. “The regular expressions are parsed against logs using the ‘sed’ tool (stream editor) which allows for excellent performance in all environments.”
BFD employs a log tracking system that allows logs to be parsed from their last read point, boosting the performance of BFD, as it is not constantly reading the same log data.
BFD can be leveraged to block attackers using tools such as APF, Shorewall, raw IP tables, IP route or custom commands. A customizable email alerting system and simple flat text files are added benefits, as is the attack pool “where trending data is stored on all hosts that have been blocked including which rule the block was triggered by.”
By default, a cron job executes BFD once every three minutes, but this can be as little as one minute without causing any performance issues.
“Although cron execution does not permit BFD to act in real time, the log tracking system ensures it never misses a beat in authentication failures,” the BFD website notes. “Further, using cron provides a reliable frame work for consistent execution of BFD in a very simplified fashion across all *nix platforms.”
BFD is free to use, but its ongoing development is dependent on public contributions and donations, so a small usage gratuity is requested.