Vulnerability Note VU#184030

MySQL fails to properly evaluate zero-length strings in the check_scramble_323() function

Overview

There is a vulnerability in the password authentication mechanism of MySQL which could allow an attacker to bypass authentication by supplying a zero-length string.

I. Description

MySQL is an open-source database system available for Microsoft Windows, Linux, and other UNIX-based operating systems. There is a vulnerability in the check_scramble_323() function that could allow an attacker to bypass authentication by supplying a "passwd_len" value of NULL. It has been reported that versions 4.1 prior to 4.1.3 and version 5.0 are affected.

Note: In order to exploit this vulnerability, an attacker would have to use a modified MySQL client library.

II. Impact

A remote, unauthenticated attacker with network access to the MySQL server could successfully authenticate without knowledge of the user's password.

III. Solution

Upgrade

According to the NGSSoftware Security Advisory, this vulnerability has been fixed in version 4.1.3 (Beta) and version 5.0 (Alpha).

Note: Users should exercise caution before installing beta or alpha releases.

Restrict access

Block or restrict access to the MySQL service (typically 3306/tcp) from untrusted networks such as the Internet.

Systems Affected

Vendor	Status	Date Notified	Date Updated
MySQL	Vulnerable	12-Jul-2004

References

http://www.nextgenss.com/advisories/mysql-authbypass.txt
http://secunia.com/advisories/12020/
http://www.securitytracker.com/alerts/2004/Jul/1010645.html
http://www.securityfocus.com/bid/10654
http://dev.mysql.com/doc/mysql/en/News-4.1.3.html

Credit

This vulnerability was reported by Chris Anley of NGSSoftware.

This document was written by Damon Morda.

Other Information

Date Public:	2004-07-01
Date First Published:	2004-07-12
Date Last Updated:	2004-07-12
CERT Advisory:
CVE-ID(s):	CAN-2004-0627
NVD-ID(s):	CAN-2004-0627
US-CERT Technical Alerts:
Metric:	5.74
Document Revision:	26

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