MySQL Authentication Vulnerabilities

Secunia Advisory: SA12020
Release Date: 2004-07-06

Critical: Moderately critical
Impact: Security Bypass
Privilege escalation Where: From local network
Software: MySQL 4.x


Chris Anley has reported two vulnerabilities in MySQL, allowing malicious people to gain access to the database or the local system.

1) MySQL fails to properly verify passwords if the client has set a specific client capability flag and specifies a “passwd_len” of NULL. This causes MySQL to accept a NULL password as a valid password and authenticates the user.

Successful exploitation requires that the attacker knows a valid username.

2) A boundary error within the handling of “scramble” strings can reportedly be exploited to execute arbitrary code if the attacker knows a password hash or through brute forcing.

The vulnerabilities only affect beta / developement branches of MySQL 4.1.x and MySQL 5.


MySQL production releases 3.x and 4.0.x are not affected.

The vulnerabilities has been fixed in version 4.1.3-beta.

Provided and/or discovered by:
Chris Anley, NGSSoftware


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