eXpBlog <= 0.3.5 Cross Site Scripting Vulnerabilities

2006-10-11T00:00:00
ID SECURITYVULNS:DOC:14627
Type securityvulns
Reporter Securityvulns
Modified 2006-10-11T00:00:00

Description

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  Advisory: eXpBlog <= 0.3.5 Cross Site Scripting Vulnerabilities

Release Date: 10/09/2006 Last Modified: 10/09/2006 Author: Tamriel [tamriel <at> gmx <dot> net] Application: eXpBlog <= 0.3.5 Risk: Low Vendor Status: contaced | replied Vendor Site: www.expblog.de

Overview:

Quote from www.expblog.de:

"Das eXpBlog ist eine beliebte Freeware weBlog Software basierend auf PHP und mySQL. Mit einem eXpBlog verfuegen Sie ueber ein flexibles und schnelles Mehrbenutzer-weBlog welches durch ein Plugin-System komfortabel erweiterbar ist."

There are some cross site scripting vulnerabilities which can be exploited by malicious people to conduct script insertion attacks.

The vulnerability has been discovered in the latest version. Other versions may also be affected.

Details:

1) Cross Site Scripting Vulnerability in kalender.php

  Arround the lines 130-140 the variable &#96;$_SERVER[&#39;PHP_SELF&#39;]&#96; is
  not properly sanitised before being used. This can be exploited
  to insert arbitrary HTML and script code, which is executed in a
  user&#39;s browser session in context of an affected site when the
  malicious data is viewed.

2) Cross Site Scripting Vulnerability in pre_details.php

  Arround the lines 15-20 the variable
  &#96;$_POST[&quot;captcha_session_code&quot;]&#96; is not properly sanitised before
  being used. This variable is used in the details.php arround
  line 152, here an attacker can insert malicious code. The
  captcha class may be affected too, because you can let it open a
  special file &#40;captcha_class.php, arround line 140&#41;.

Proof of Concept:

1) details.php/%3E%22%3E%3Cscript%3Ealert('Unsecure')%3C/script%3E

2) comment=1&captcha_session_code=>"><script>alert('hole')</script>...

Solution/Fix:

  Edit the source code to ensure that input is properly sanitised.
  Use functions like PHP&#96;s htmlentities&#40;&#41; function.

Disclosure Timeline:

  10/03/2006 - Discovery of the vulnerabilities
  10/03/2006 - Contacted the vendor
  10/04/2006 - Vendor reponse
  10/09/2006 - Supplied bugfix to the official forum
  10/09/2006 - Public disclosure

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