Gray Hat hackers have posted proof-of-concept code for a worm designed to spread using vulnerabilities in Oracle's database software. The Oracle Voyager worm, which targets Oracle databases with default user accounts and passwords, was posted on a full disclosure list on Monday (31 October). Although not a threat in itself, security researchers fear the code might be used as a template to develop future malware.

The worm uses the a net connection package (called UTL_TCP) to scan for Oracle databases on the same local network. Once it finds another database, the SID is retrieved and the worm uses several default username and password combinations to attempt to log onto the remote database. The proof-of-concept worm is harmless but possible follow-up code may not be so polite.

"In its current state, the worm isn't a terribly significant threat. However, is can be treated as an early warning sign for future variants of the worm that include additional propagation methods," according to a posting by the SANS Institute's Internet Storm Centre, an organisation which tracks net-based threats.

The scope of the potential threat remains unclear. Security experts nonetheless urge Oracle system administrators to take precautions to shore up security defence. US-CERT, for example, offers the following advice:

• Change default user credentials for Oracle installations
• Change the default port for the TNS listener
• Restrict Oracle network access to trusted hosts only
• Revoke CREATE DATABASE LINK privileges from the CONNECT role

The emergence of what's said to be the first worm targeting Oracle databases illustrates that malicious code is ceasing to be a Windows only concern as malware authors look to exploit security holes beyond the desktop. A detailed analysis of the Oracle Voyager worm by Red Database Security can be found here. ®