Secunia

l0om has discovered two vulnerabilities and a security issue in Guestbox, which can be exploited by malicious people to disclose potentially sensitive information, bypass certain security restrictions, and conduct script insertion attacks.

1) An error in the authentication process can be exploited to post comments without being authenticated as the administrator.

2) Input passed to the "url" parameter in "guestbox.php" when posting an entry isn't properly sanitised before being used. This can be exploited to inject arbitrary HTML and script code, which will be executed in a user's browser session in context of an affected site when the malicious entry is viewed.

Successful exploitation requires that "magic_quotes_gpc" is disabled.

3) The problem is that users' IP addresses are stored insecurely in the "gblog" file inside the web root and can be exposed.

The vulnerabilities and the security issue have been confirmed in version 0.6. Other versions may also be affected.

Solution
Update to version 0.8 and restrict web access to the "gblog.dat" file (e.g. with a .htaccess file) or move it outside the webroot.
Further details available in Customer Area

Provided and/or discovered by
l0om

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