Update searchHash() to handle single-line file

[jawaad-ahmad]

Povl Ole Haarlev Olsen commented on the original blog on 25 Apr 2015 (https://blog.rootshell.be/2010/11/03/bruteforcing-ssh-known_hosts-files/) stating:

... a known_hosts file with only one line where I knew the correct hostname beforehand. Unfortunately your program couldn’t find anything...

In searchHash() you return 0, if the $host doesn’t match any of the lines and the line number(*) if it does. Unfortunately the first line is line number 0 and the code therefore won’t show any matches for the first (and maybe only) entry in known_hosts, no matter how long you’ll let it run.

Quick fix: Change searchHash() to return $i+1; on success and remove the “+ 1”-part from the various printf(“*** Found host: %s (line %d) ***\n”, $tmpHostShort, $line + 1); lines.

(*) It’s not really the line number, since you only increment $idx if ($hostHash =~ m/|1|/). Maybe store the real line numbers too and use those for the output? ($. might be useful.)

Here is the original searchHash() from https://blog.rootshell.be/wp-content/uploads/2010/11/known_hosts_bruteforcer.pl.txt that is referenced in the comment:

#
# Generate SHA1 hashes of a hostname/IP and compare it to the available hashes
# Returns the line index of the initial known_hosts file
#
sub searchHash() {
	$host = shift;
	($host) || return 0;

	# Process the list containing our hashes
	# For each one, generate a new hash and compare it
	for ($i = 0; $i < scalar(@saltStr); $i++) {
		$decoded = decode_base64($saltStr[$i]);
		$hmac = Digest::HMAC_SHA1->new($decoded);
		$hmac->add($host);
		$digest = $hmac->b64digest;
		$digest .= "="; # Quick fix ;-)
		if ($digest eq $base64Str[$i]) {
			return $i;
		}
	}
	return 0;
}