In a shocking move, cyber criminals recently hacked the Linux Mint Web server and used it to launch an attack against the popular distro's user base.

The hackers managed to alter the official Linux Mint Web site to point to an infected ISO image. The infected image contains a valid installation of Linux Mint 17.3 Cinnamon edition, along with the Tsunami IRC backdoor. The backdoor allows the cyber criminals to access the unsuspecting user's system, steal data and gain control over the software and hardware.

The hack occurred on the night of the 20th of February and was detected the next day. Any users who downloaded and installed Linux Mint 17.3 Cinnamon edition during that period are at risk. Users who installed Mint before or after that date are not at risk.

The Mint team responded by taking the site down while they worked to patch the hole. They worked for more than a week to make their Web servers much more secure. This involved isolating the specific weaknesses that allowed the attack and hardening their system against future abuses.

The Tsunami backdoor, which was installed on the infected ISO image, is usually used by attackers to launch distributed denial-of-service attacks (DDOS). These attacks use infected machines to flood Web servers with malicious traffic, preventing legitimate users from accessing services.

But Tsunami has other darker uses too. It provides access to the local filesystem and any sensitive information that may be installed on the computer.

The attack was made possible by a weakness in the WordPress blog used on the official Mint site. This weakness gave the attackers root access to the Web server. They used this to alter public files on the site, pointing a download link to a malicious FTP site in Bulgaria. Unsuspecting users would assume the link was valid, as it was posted on an official Web site.

Now that the official Linux Mint Web site has been fixed, the offending links are gone. Moving forward, the Mint team is working to improve the security of the installation process, so users can verify that they have downloaded a legitimate ISO before installing it.

In one sense, an increase in attacks against desktop Linux systems is to be expected. As the user base grows, Linux distros become a more tempting target to cyber criminals. That means users can't afford to be complacent and assume that "malware affects only Windows".

Users have to take every precaution to keep their systems up to date and secure. Distributors have to crack down on security weaknesses and make it harder to exploit Linux systems. And, everyone has to work together to respond to the inevitable attacks that will occur.

In spite of the attacks, Linux Mint is still a great choice for the security-conscious. As with any software, it's important for users and developers to remember to be cautious and practice good security.