The third Linux worm this year, which tries to exploit lax security on Web sites running the open source OS, has been discovered.

Adore, which is similar to the earlier Ramen and Lion worms, scans Linux hosts on the Internet to determine whether they are vulnerable to well known exploits.

These include a well publicised vulnerability with BIND, as well as security weaknesses that may be present within Linux services called LPRng, rpc-statd and wu-ftpd (which may be left insecure in default installations).

On hosts with vulnerabilities, the Adore worm replaces a system binary, called ps, with a Trojaned version which creates backdoor access to compromised host.

The worm replaces an Internet service, known as ICMP (Internet Control Message Protocol), with a version containing a back door feature that allows a hacker access to systems whenever a properly formatted command sequence is received over the Internet. Adore also attempt to send sensitive system information to four different email addresses.

According to the SANS (System Administration, Networking, and Security) Institute, Adore appears to have begun spreading on April Fool's Day. Antivirus firms are in the process of updating protection to detect the bug and early indications are that the worm, though dangerous, is not spreading particularly quickly.

SANS, a co-operative research and education body with over 96,000 members, has developed a utility called adorefind that is designed to detect and remove the worm from an infected system. This utility can be downloaded from here. ®

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