Advisory: Authentication bypass in phpBannerExchange

RedTeam identified two SQL injections in phpBannerExchange. It is
possible to bypass user authentication with them.

Details

Product: phpBannerExchange
Affected Versions: All versions up to phpBannerExchange 2.0 RC5
Fixed Versions: 2.0 RC6
Vulnerability Type: SQL injections
Security-Risk: medium
Vendor-URL: http://www.eschew.net/scripts/phpbe/2.0/
Vendor-Status: informed, fixed version released
Advisory-URL: http://www.redteam-pentesting.de/advisories/rt-sa-2006-004.txt
Advisory-Status: public
CVE: CVE-2006-3012
CVE-URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-3012

Introduction

From the vendor's homepage:
phpBannerExchange is a PHP/mySQL script that allows virtually anyone
with minimal knowledge of PHP, mySQL and web hosting to run their own
banner exchange.

More Details

In file "client/stats.php" the variables $login and $pass are not
sanitized at all.

[…]
42 $login=$_REQUEST['login'];
43 $pass=$_REQUEST['pass'];
[…]

If plaintext password are allowed ($usemd5 != "Y"), following SQL query
is used:

[…]
59 $result = mysql_query("select * from banneruser where
login='$login' AND pass='$pass'");
[…]

By passing the special character "'" it is possible to alter the SQL
query and bypass authentication.

A similar vulnerability exists in "admin/stats.php":

[…]
49 $login=$_SESSION['login'];
50 $pass=$_SESSION['pass'];
[…]
54 $result = mysql_query("select * from banneradmin where
adminuser='$login'
AND adminpass='$encpw'");
[…]

Proof of Concept

User login or administrator login:
Use "'or''='" for both login name and password. You will be
authenticated as the first user/admin in the database.

Workaround

Use PHP Magic Quotes.

Fix

Upgrade to version 2.0 RC6

Security Risk

The security risk is high because an attacker could gain access to an
administrator account and view and alter the database and hereby
compromise the whole application.

History

2006-06-09 Discovery of the problem
2006-06-10 Vendor is informed
2006-06-12 Vendor releases fixed version

References

[1] http://www.eschew.net/scripts/phpbe/2.0/

RedTeam

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pentests, performed by a team of specialised IT-security experts.
Hereby, security weaknesses in company networks are uncovered and can be
fixed immediately.

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knowledge and enhance the public knowledge with research in security
related areas. The results are made available as public security
advisories.

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