CDE Vulnerability Opens Unix Systems Up to Attacks

Security researchers have identified a serious vulnerability in the Common Desktop Environment GUI used by many Unix systems that could enable a remote attacker to gain root privileges on a target machine.

The flaw is a buffer overflow in the subprocess control server, which is typically started by the Internet service daemon when the CDE client tries to create a process on the daemons host. Using the new vulnerability, an attacker could create a special CDE client request that would enable him to execute arbitrary commands on the target system, according to an advisory published by Internet Security Systems Inc.s X-Force research team.

The subprocess control daemon runs by default on all operating systems with CDE installed.

Several Unix vendors are affected by the vulnerability, including Caldera Inc., Hewlett-Packard Co. and Sun Microsystems Inc.

Only a few of the vendors have patches available right now, and the others are working on them.

Security experts say that although it is somewhat difficult to exploit the vulnerability, it is likely only a matter of time before someone writes a worm to automate the exploitation.

“Were very concerned about it turning into a worm because there are so many vendors involved,” said Dan Ingevaldson, team leader at the X-Force in Atlanta.

ISS and the CERT Coordination Center worked together on the advisory and hadnt planned to send it out until December. However, Caldera issued its own bulletin earlier this month, forcing the hand of the researchers.

The incident underscores the need for a consensus on the responsible handling of vulnerabilities, said Ingevaldson.

“This is just what we were talking about last week,” Ingevaldson said, referring to discussions at the Microsoft Corp. Trusted Computing forum on vulnerability reporting. “Multivendor issues are always a big deal, and its hard to coordinate everything.”

CDE is a GUI environment that ships with many versions of Unix.

The complete list of vulnerable Unix variants as well as the advisory can be found at the CERT Web site, www.cert.org.