Bug 14412: SQL injection possible

There is a SQL Injection vulnerability in the
/cgi-bin/koha/opac-tags_subject.pl script.

By manipulating the variable 'number', the database can be accessed
via time-based blind injections.

The following string serves as an example:

/cgi-bin/koha/opac-tags_subject.pl?number=1+PROCEDURE+ANALYSE+(EXTRACTVALUE(9743,CONCAT(0x5c,(BENCHMARK(5000000,MD5('evil'))))),1)

To exploit the vulnerability, no authentication is needed

To test
1/ Turn on mysql query logging
2/ Hit /cgi-bin/koha/opac-tags_subject.pl?number=1+PROCEDURE+ANALYSE+(EXTRACTVALUE(9743,CONCAT(0x5c,(BENCHMARK(5000000,MD5('evil'))))),1)
3/ Check the logs notice something like
  SELECT entry,weight FROM tags ORDER BY weight DESC LIMIT 1
  PROCEDURE ANALYSE
  (EXTRACTVALUE(9743,CONCAT(0x5c,(BENCHMARK(5000000,MD5('evil'))))),1)
4/ Apply patch
5/ Hit the url again
6/ Notice the log now only has
   SELECT entry,weight FROM tags ORDER BY weight DESC LIMIT 1

Signed-off-by: Jonathan Druart <jonathan.druart@koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Confirmed the problem and the fix for it.
Signed-off-by: Tomas Cohen Arazi <tomascohen@unc.edu.ar>

diff --git a/opac/opac-tags_subject.pl b/opac/opac-tags_subject.pl
index d879d51..590e7a5 100755 (executable)
--- a/opac/opac-tags_subject.pl
+++ b/opac/opac-tags_subject.pl
@@ -51,8 +51,8 @@ my ( $template, $loggedinuser, $cookie ) = get_template_and_user(
 
 my $number = $query->param('number') || 100;
 
-my $sth = $dbh->prepare("SELECT entry,weight FROM tags ORDER BY weight DESC LIMIT $number");
-$sth->execute;
+my $sth = $dbh->prepare("SELECT entry,weight FROM tags ORDER BY weight DESC LIMIT ?");
+$sth->execute($number);
 
 my %result;
 my $max=0;