Lucian Constantin
CSO Senior Writer

Hackers infect MySQL servers with malware for DDoS attacks

news
Oct 29, 20152 mins

SQL injection is used to abuse a MySQL feature and install malware on servers

Data center servers
Credit: Pixabay

Hackers are exploiting SQL injection flaws to infect MySQL database servers with a malware program that’s used to launch distributed denial-of-service (DDoS) attacks.

Security researchers from Symantec found MySQL servers in different countries infected with a malware program dubbed Chikdos that has variants for both Windows and Linux.

This Trojan is not new and was first documented in 2013 by incident responders from the Polish Computer Emergency Response Team (CERT.PL). At that time the malware was being installed on servers after using brute-force dictionary attacks to guess SSH (Secure Shell) login credentials.

However, the new attacks observed by Symantec abuse the user-defined function (UDF) capability of the MySQL database engine. UDF allows developers to extend the functionality of MySQL with compiled code.

Symantec believes that attackers exploit SQL injection vulnerabilities in order to inject malicious UDF code in databases. They then use the DUMP SQL command to save the injected code as a library file that is later executed by the MySQL process.

The malicious UDF code downloads and installs the Chikdos Trojan, which allows attackers to abuse the server’s bandwidth for DDoS attacks.

The Symantec researchers found MySQL servers infected with Chikdos in many countries, including India, China, Brazil, Netherlands, the United States, South Korea, Mexico, Canada, Italy, Malaysia, Nigeria, and Turkey. The largest concentrations were in India and China, 25 and 15 percent respectively.

During their analysis the researchers saw the servers being used to launch DDoS attacks against a U.S. hosting provider and a Chinese IP address.

The reason for targeting MySQL servers is likely because their bandwidth is considerably larger than that of regular PCs, making them more suitable for large DDoS campaigns, the Symantec researchers said in a blog post.

To prevent such attacks, website owners should avoid running SQL servers with administrative privileges and should follow best programming practices for mitigating SQL injection vulnerabilities, they said.

Lucian Constantin

Lucian Constantin writes about information security, privacy, and data protection for CSO. Before joining CSO in 2019, Lucian was a freelance writer for VICE Motherboard, Security Boulevard, Forbes, and The New Stack. Earlier in his career, he was an information security correspondent for the IDG News Service and Information security news editor for Softpedia.

Before he became a journalist, Lucian worked as a system and network administrator. He enjoys attending security conferences and delving into interesting research papers. He lives and works in Romania.

You can reach him at lucian_constantin@foundryco.com or @lconstantin on X. For encrypted email, his PGP key's fingerprint is: 7A66 4901 5CDA 844E 8C6D 04D5 2BB4 6332 FC52 6D42

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