Secunia

Multiple vulnerabilities have been discovered in YaPiG, which can be exploited by malicious people to conduct cross-site scripting, script insertion, and cross-site request forgery attacks.

1) Input passed to the "Website" field when adding a comment is not 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 comment is viewed.

2) Input passed to the "img_size" parameter in view.php and the "D_REFRESH_URL" parameter in template/default/thanks_comment.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 a vulnerable site.

Successful exploitation requires that "register_globals" is enabled.

3) An error caused due to the application allowing users to perform certain actions via HTTP POST requests without performing any validity checks to verify the user's request, can be exploited to perform certain administrative tasks.

This can further be exploited to inject arbitrary PHP code into the guid_info.php file via the "title" field when modifying a gallery.

4) Input passed to the "I_ADD_COMMENT" parameter in template/default/add_comment_form.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 a vulnerable site.

5) Input passed to the "I_ADMIN_TASKS" parameter in template/default/admin_task_bar.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 a vulnerable site.

6) Input passed to the "I_SELECT_OPT" parameters in /template/default/delete_gallery_form.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 a vulnerable site.

7) Input passed to the "I_TITLE" parameter in template/default/face_begin.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 a vulnerable site.

Successful exploitation of the vulnerabilities #4 to #7 requires that "register_globals" is enabled.

8) Input passed to the "interval" parameter in slideshow.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 a vulnerable site.

Successful exploitation requires that a gallery exists.

The vulnerabilities have been confirmed in version 0.95b. Other versions may also be affected.

Solution
Edit the source code to ensure that input is properly verified and sanitised or use a different product.

Provided and/or discovered by
1 - 3) Nenad Jovanovic, Secure Systems Lab, Technical University of Vienna.
2) Kuon, Armorize Security Team.
4 - 8) High-Tech Bridge SA Security Research Lab

Changelog
Further details available in Customer Area

Original Advisory
International Secure Systems Lab:
http://www.seclab.tuwien.ac.at/advisories/TUVSA-0510-001.txt

HTB22962:
http://www.htbridge.ch/advisory/multiple_xss_in_yapig.html

Deep Links
Links available in Customer Area