Malicious hackers have launched a zero-day bot attack against default Windows installations of the MySQL database engine, infecting vulnerable systems at the rate of 100 per minute, security experts warned on Thursday.

The bot takes advantage of the publicly released "MySQL UDF Dynamic Library Exploit" to break into the open-source MySQL package. Once a database is hijacked, infected systems will connect to an IRC (Internet Relay Chat) server and retrieve propagation instructions.

Johannes Ullrich, chief technology officer at the SANS Internet Storm Center, said his handlers discovered more than 8,000 hosts connected to the IRC server during the day on Thursday.

MySQL is a freely available database engine designed to provide fast access to stored data. It is installed on more than 8 million systems worldwide, according to MySQL AB, the Cupertino, Calif.-based firm that develops and manages the program.

Because of the wild popularity of MySQL, it is likely that many more MySQL systems could be infected but blocked from connecting to the swamped IRC server, Ullrich told eWEEK.com.

In order to launch the exploit, Ullrich said the bot first has to authenticate to "mysql" as "root" user. Once authenticated, brute-force attacks are launched using a list of passwords included with the bot.

Jacques Erasmus, security consultant at host intrusion detection firm Prevx, said the hijacked database engines are creating a zombie network of machines capable of being misused.

Attacking all MySQL Windows installations, Erasmus said the bot, identified as MySpooler, opens three listening ports on the target machine and drops in an eight-character random file name.

He said MySpooler also provides a backdoor for the attack to access the machine and deliver payload.

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According to an advisory from the SANS ISC, the bot creates a table called "bla" using the database "mysql," which is typically used to store such administrative information as passwords.

Ullrich said the bot includes the usual set of bot features such as a DDoS (distributed denial of service) engine, various scanners, commands to solicit information like system stats and software registration keys from infected systems.

"This bot does not use any vulnerability in MySQL. The fundamental weakness it uses is a weak 'root' account," he said.

The SANS ISC recommends that MySQL users select a strong password for the "root" account on Windows installations. Administrators should also set up restricted access to root accounts and apply firewall rules to make sure MySQL servers are not exposed to attackers.

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