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Problem with customized login pages for Oracle SSO
From: advisories () madison-gurkha com
Date: Tue, 30 Mar 2004 19:24:51 +0200
Name: Problem with customized login pages for Oracle SSO
Authors: Guido van Rooij (Madison Gurkha)
Arjan de Vet (Madison Gurkha)
Application: All known versions
Platforms: All supported platforms
Oracle has a Single Sign-on application called OSSO.
Among others, it has a web based login form. This form can be
customized as explained in "Oracle 9iAS Single Sign-on
Administrators Guide, Release 2(9.0.2), Part No. A96115-01". In
this document, a sample login form is published (section 8).
The problem with this login form is that it can be abused by
unauthorized persons to gain access to the supplied usercode and
password. This can be done by tricking a valid user to open a
URL that is the real URL of the customized SSO login page but
with a modified URL parameter.
The problem is that the attack makes use of the real login page.
Thus, if users check host certificates only, they will not be
able to detect that they are being tricked. Also, after logging
in, they can be redirected to the proper application on the
intended system to hide the fact that usercode and password have
Note that the problem is a design problem in the way custom
login pages must be implemented, not a problem with a sample
Users can accidentally reveal their SSO usercode/password
combination to unauthorized persons.
Oracle came with the following solution:
The p_submit_url value in the customized login page can be
hard-coded. This will mitigate this issue since it will not be
an input value to the page anymore. The p_submit_url URL value
in the 902 SSO server is in the following format:
We recommend implementing the proposed solution.
Of course, we hope that Oracle will update its documentation as
well such that the p_submit_url parameter will be removed from
all example code.
2004-01-12: vendor informed
2004-02-18: vendor came with solution
2004-03-10: communicated solution
Full-Disclosure - We believe in it.
- Problem with customized login pages for Oracle SSO advisories (Mar 30)