Sybase has issued a security patch for three vulnerabilities affecting the newest versions of its database software that could allow a malicious hacker to gain control of a Sybase server and run arbitrary code on it.

Sybase said it wasn't aware of any systems that have been affected by the problem, but advised customers to download and install the patches, which were made available on its Web site last week.

The security holes can be used to create a "buffer overflow," a memory problem frequently exploited in cyberattacks. The holes affect users running the latest versions of its Adaptive Server database, versions 12.0 and 12.5, on both Unix and Windows platforms, said Application Security, which discovered the problem.

Sybase downplayed the risk. The vulnerabilities are "predominantly hypothetical" and can be exploited only by those who are able to log into a system as a "trusted user," said Tom Traubitz, a Sybase senior marketing manager.

Application Security, which called the vulnerabilities "high risk," disagreed.

"A non-privileged user can execute these things; we stand by that," said Stephen Grey, an Application Security marketing manager.

One exploit uses the command "DROP DATABASE."

"This is meant to only be run by privileged users, however if a non-privileged user runs this command, the buffer overflow occurs before any access control takes place," Application Security said on its Web site. "Therefore a non-privileged user can use this security hole to take complete control of a Sybase server."

Application Security has posted a description of the vulnerabilities on its Web site.

The IDG News Service is a Network World affiliate.