Feeds

‘Friendly’ Cheese worm reveals many compromised boxes

And it's a tiny step from being highly destructive, too

  • alert
  • submit to reddit

Secure remote control for conventional and virtual desktops

The so-called 'cheese worm' has attracted a great deal of attention in the past 24 hours for its benign payload, which seeks to mend Linux boxes infected with at least one version of the li0n worm (which exploits a BIND vulnerability). However, it also demonstrates that there's a large number of already-compromised machines connected to the Net; and furthermore, a tiny modification to its code could render it immensely destructive.

The worm scans for machines with a secure root shell listening on TCP port 10008, as set up by a variant of the li0n worm. If the shell exists, cheese will install in the directory /tmp/.cheese and execute a script thus:

/tmp/.cheese/go:
#!/bin/sh
nohup ./cheese $1 1>/dev/null 2>&1 &

Cheese reads the file inetd.conf and rewrites it, deleting any line that contains the string /bin/sh. It then restarts inetd, with all /bin/sh processes killed indiscriminately.

"Until the 'cheese' process is somehow killed, it repeats a cycle of scanning semi-random /16 (e.g., class B) network blocks for hosts listening on TCP port 10008 using the 'psm' program," a detailed incident report by the Computer Emergency Response Team Coordination Center (CERT/CC) at Carnegie Mellon University explains.

The first octet of the address may be from 193 to 218; and the second may be from 1 to 254, Cert/CC says.

What's most interesting here is that cheese may be the first worm which automates the exploitation not of an existing vulnerability, as most do, but of an existing compromise.

"This is perhaps the first successful example of this type of exploit," CERT/CC artifact analysis team leader Kevin Houle told The Register.

Houle believes that the example here, while relatively harmless in itself, is alarming.

"We've seen an increase in reconnaissance (scanning) related to port 10008," he observes -- an increase which strongly implies activity by the cheese worm.

That, in turn, implies that there is quite a large number of machines already compromised, whose owners remain blithely ignorant of the fact. Call it proof-of-concept that the Net is teeming with already-rooted boxes.

He also emphasizes that it would be child's play to modify cheese for extremely destructive activity. Developing destructive exploits for existing compromises is not a trend Houle would like to see carried forward -- and we'll just second that ourselves. ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Phones 4u slips into administration after EE cuts ties with Brit mobe retailer
More than 5,500 jobs could be axed if rescue mission fails
Apple CEO Tim Cook: TV is TERRIBLE and stuck in the 1970s
The iKing thinks telly is far too fiddly and ugly – basically, iTunes
Huawei ditches new Windows Phone mobe plans, blames poor sales
Giganto mobe firm slams door shut on Microsoft. OH DEAR
Phones 4u website DIES as wounded mobe retailer struggles to stay above water
Founder blames 'ruthless network partners' for implosion
Found inside ISIS terror chap's laptop: CELINE DION tunes
REPORT: Stash of terrorist material found in Syria Dell box
Show us your Five-Eyes SECRETS says Privacy International
Refusal to disclose GCHQ canteen menus and prices triggers Euro Human Rights Court action
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
Saudi Petroleum chooses Tegile storage solution
A storage solution that addresses company growth and performance for business-critical applications of caseware archive and search along with other key operational systems.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.