X-Git-Url: http://git.ipfire.org/?p=people%2Fstevee%2Fguardian.git;a=blobdiff_plain;f=modules%2FParser.pm;h=4f03bf958064598ff5e9a38974f6ea46805bb713;hp=ad55d20085afdee3ec106cc587c6f053e1249ebf;hb=7587e837c071ac35993b942e1786deca87abdc51;hpb=ebd440a9314ad6a179403b6938f3a182bf2278d5

diff --git a/modules/Parser.pm b/modules/Parser.pm
index ad55d20..4f03bf9 100644
--- a/modules/Parser.pm
+++ b/modules/Parser.pm
@@ -4,12 +4,13 @@ use warnings;
 
 use Exporter qw(import);
 
-our @EXPORT_OK = qw(Parser);
+our @EXPORT_OK = qw(IsSupportedParser Parser);
 
-# This hash contains all supported logfiles and which function
-# has to be called to parse them in the right way.
+# This hash contains all supported parsers and which function
+# has to be called to parse messages in the right way.
 my %logfile_parsers = (
-	"/var/log/snort/alert" => \&message_parser_snort,
+	"snort" => \&message_parser_snort,
+	"ssh" => \&message_parser_ssh,
 );
 
 #
@@ -20,18 +21,47 @@ my %logfile_parsers = (
 ## any action should be performed.
 #
 sub Parser ($$) {
-        my ($file, @message) = @_;
+        my ($parser, @message) = @_;
 
 	# If no responsible message parser could be found, just return nothing.
-	unless (exists($logfile_parsers{$file})) {
+	unless (exists($logfile_parsers{$parser})) {
 		return;
 	}
 
-	# Call responsible logfile parser.
-	my $action = $logfile_parsers{$file}->(@message);
+	# Call responsible message parser.
+	my $action = $logfile_parsers{$parser}->(@message);
 
-	# Return which action should be performed.
-	return "count $action";
+	# In case an action has been returned, return it too. 
+	if (defined($action)) {
+		# Return which action should be performed.
+		return "count $action";
+	}
+
+	# Return undef, no action required.
+	return undef;
+}
+
+#
+## IsSupportedParser function.
+#
+## This very tiny function checks if a given parser name is available and
+## therefore a supported parser.
+#
+## To perform these check, the function is going to lookup if a key in the
+## hash of supported parsers is available
+#
+sub IsSupportedParser ($) {
+	my $parser = $_[0];
+
+	# Check if a key for the given parser exists in the hash of logfile_parsers.
+	if(exists($logfile_parsers{$parser})) {
+		# Found a valid parser, so return nothing.
+		return 1;
+	}
+
+	# Return "False" if we got here, and therefore no parser
+	# is available.
+	return;
 }
 
 #
@@ -48,4 +78,55 @@ sub message_parser_snort($) {
 	return "$message[0] SNORT A simple Snort Message";
 }
 
+#
+## The SSH message parser.
+#
+## This subfunction is used for parsing and detecting different attacks
+## against the SSH service.
+#
+sub message_parser_ssh (@) {
+	my @message = @_;
+
+	# The name of the parser module.
+	my $name = "SSH";
+
+	# Variable to store the grabbed IP-address.
+	my $address;
+
+	# Variable to store the parsed event.
+	my $message;
+
+	# Loop through all lines, in case multiple one have
+	# been passed.
+	foreach my $line (@message) {
+		# Check for failed password attempts.
+		if ($line =~/.*sshd.*Failed password for (.*) from (.*) port.*/) {
+			# Store the grabbed IP-address.
+			$address = $2;
+
+			# Set event message.
+			$message = "Possible SSH-Bruteforce Attack for user: $1.";
+		}
+
+		# This should catch Bruteforce Attacks with enabled preauth
+		elsif ($line =~ /.*sshd.*Received disconnect from (.*):.*\[preauth\]/) {
+			# Store obtained IP-address.
+			$address = $1;
+
+			# Set event message.
+			$message = "Possible SSH-Bruteforce Attack - failed preauth.";
+		}
+	}
+
+	# Check if at least the IP-address information has been extracted.
+	if (defined ($address)) {
+		# Return the extracted values and event message.
+		return "$address $name $message";
+	}
+
+	# If we got here, the provided message is not affected by any filter and
+	# therefore can be skipped. Return nothing (False) in this case.
+	return;
+}
+
 1;