Stefan Schurtz has discovered multiple vulnerabilities in MGB, which can be exploited by malicious users to conduct SQL injection attacks and by malicious people to conduct cross-site scripting attacks.

1) Input passed via the "p" parameter to index.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

2) Input passed via the "name", "city", "email", "icq", "aim", "msn", "hp", and "message" parameters to newentry.php is not properly sanitised in the "template()" function in includes/functions.inc.php before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

3) Input passed via the "id" parameter to admin/admin.php (when "action" is set to "delete") is not properly sanitised in admin/delete.inc.php before being used in SQL queries. This can be exploited to manipulate SQL queries by injecting arbitrary SQL code.

Successful exploitation of this vulnerability requires the "Delete post" permission.

The vulnerabilities are confirmed in version 0.6.9.1. Prior versions may also be affected.

Solution
Update to version 0.6.9.2.

Provided and/or discovered by
Stefan Schurtz.

Changelog
Further details available to Secunia VIM customers

Original Advisory
SSCHADV2012-017:
http://www.darksecurity.de/index.php?/219-SSCHADV2012-017-MGB-OpenSource-Guestbook-0.6.9.1-Multiple-security-vulnerabilities.html

Deep Links
Links available to Secunia VIM customers