Linux/Kork

Threat description

Details

CATEGORYMalware
TYPEWorm
PLATFORMLinux

Summary

Kork is a worm that uses the known vulnerability in lpd service to propagate from a vulnerable Linux system to another. This service is part of the default installation of Red Hat Linux 7.0.



Removal

Automatic action

Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.

More scanning & removal options

More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.

You may also refer to the Knowledge Base on the F-Secure Community site for more information.

Contact Support

F-Secure customers can request support online via the Request support or the Chat forms on our Home - Global site.

Technical Details


Variant:Kork.A

If the worm finds a vulnerable host, it first creates two users, "kork" and "kork2", to the system without a password. "kork2" user has a root priviledge.

Kork also adds an open shell to port 666.

Next it attempts to download a trojanized login and the main part of the trojan from a web site. Since April 26th, 2001, neither of these files are available, so the worm cannot replicate any further. However, already infected machines are able to compromise other vulnerable machines by adding an open shell and users to the system.

If the download is completed, the worm installs trojanized "/bin/login" and "/bin/ps" to the system. It attemps to send sensitive system data propably to the virus writer.

Original "/bin/ps" is copied to "/usr/bin/.ps" and the original "/bin/login" is copied to "/bin/.login".

Finally the worm starts to scan random Class-B subnets for vulnerable hosts.

The vulnerability in the lpd daemon is known and already fixed within updated provided by Red Hat at: https://www.redhat.com/support/errata/rh7-errata-security.html

Submit a Sample

Suspect a file or URL was wrongly detected? Send it to our Labs for further analysis

Submit a Sample

Give And Get Advice

Give advice. Get advice. Share the knowledge on our free discussion forum.

More Info