Three vulnerabilities have been identified in BlackBook, which can be exploited by malicious people to gain knowledge of sensitive information.

Missing input validation makes it possible to conduct Cross-Site Scripting attacks against visitors. This can be exploited by posting a message and including script code in any field except the message body. The script code will be executed in a visitors browser when viewing the guest book.

Successful exploitation may result in disclosure of various information (eg. cookie-based authentication information) associated with the site running BlackBook or inclusion of malicious content, which the user thinks is part of the real website.

Due to an access control error anyone can access the file "data.dat" in the "data/" directory. This discloses various information including other users' IP addresses.

The file "phpinfo.php" discloses various system information, which could help a malicious person during the preliminary information gathering phases of an attack.

The vulnerabilities have been reported in version 1.0.

Solution
Use another guest book.
Further details available to Secunia VIM customers

Provided and/or discovered by
Donnie Werner

Original Advisory
http://exploitlabs.com/files/advisories/EXPL-A-2003-015-blackbook.txt

Deep Links
Links available to Secunia VIM customers