Worm tries to fix infected Linux systems

The worm was identified early last week as reports of certain types of heightened network activity began to be seen, according to Kevin Houle, the artifacts analysis team leader at the Computer Emergency Response Team Coordination Center (CERT/CC). CERT/CC has issued an incident note about the worm.

Lion attacked Linux servers running a vulnerable version of BIND, the Berkeley Internet Name Domain server, stealing passwords and installing and hiding hacking tools on systems it infected. Systems compromised by Lion are open to attack at port 10008. A port is an address on an Internet host typically dedicated to handling a particular communications protocol. HTTP (hypertext transfer protocol) uses port 80 and FTP (file transfer protocol) uses port 21, for instance. A machine infected with Lion is available for use in further attacks.

Cheese scans computers looking for a vulnerability at port 10008 and enters in the same way. Once in the system, however, Cheese changes a number of files and attempts to close the hole, or backdoor, left by Lion, Houle said.

The attempt to close the backdoor "is very simplistic and won't be successful in all cases," though it might succeed in some, he said.

This is not the first worm that has attempted to clean up after other worms and close the doors they have left, Houle said. Worms have attempted to shut backdoors so as to protect compromised machines for the original attacker, keeping them from being taken over by others, since the advent of easy-to-use worm-writing kits, he said.

In addition to patching holes, Cheese leaves a file on servers it infects, which says it makes changes "to stop pesky haqz0rs (hackers) messing up your box even worse than it is already. This code was not written with malicious intent. In fact, it was written to try and do some good," according to a reader of the Incidents mailing list, where much early discussion of the worm took place.

Whether system administrators ought to be thankful for this attempt at beefing up their security is another matter.

Using one worm to patch backdoors left by another "may seem like a good idea, but it's not," Houle said.

"Anything that makes unauthorised access into a system and changes system files and uses it to (in essence) attack another system" should not be welcome by any systems administrator, he said. "While it might be an interesting thought, it's really not a good solution."

A better solution, Houle said, is for systems administrators to keep up to date on security issues regarding the systems they use and patch their machines as soon as bug fixes are released. Rather than truly fixing the problem, the presence of Cheese on a system is only a symptom, he said. If Cheese is present, that is an indication that the server is vulnerable to the sort of attack these worms exploit and ought to be patched immediately, he said.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Sam Costello

PC World
Show Comments

Cool Tech

Breitling Superocean Heritage Chronographe 44

Learn more >

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?