The security holes could allow a hacker to break into the servers, steal data, deface Web sites or substitute false data for information a company provides to its customers, according to PGP Security, a Network Associates business unit.
FTP servers are used by more than 90 per cent of all enterprise networks to share data with employees, partners and customers, and the vulnerability could affect a significant portion of those networks, PGP Security said.
The COVERT lab isn't aware of any serious failures attributed to the vulnerability, but as news of the security hole spreads, "it's kind of a race to see if vendors can patch their systems before they are exploited by the bad guys," said Jim Magdych, manager of COVERT Lab.
The problem was discovered in Unix systems from Sun Microsystems, Silicon Graphics and Hewlett-Packard, Magdych said. PGP Security is working with these vendors so they can provide patches, he said. In addition, COVERT is working with other vendors to help them confirm whether their servers are vulnerable and to get patches out to their end users.
Sun, HP and SGI didn't immediately return calls seeking comment for this story.
The vulnerability is linked to the "glob" function, which is programming shorthand for a function that allows users to conduct a search using a truncated version of a name or a word. When the glob function is used it often returns more data than expected to the FTP server, causing it to overflow the buffer. This is a common type of vulnerability which leaves that data open to exploitation by software that can be written to alter it, Magdych said.
"If someone could compromise the FTP server, they could potentially replace Web sites, deface them or replace files with Trojan (virus) programs," Magdych said. Trojan programs would be especially insidious because they can be set up to run when unsuspecting users try to download a patch.
The notification about the FTP vulnerability follows the lab's warning in January of a possible vulnerability in the software used in most DNS (Domain Name System) servers. Magdych said the efforts were a continuation of COVERT lab's efforts to identify vulnerabilities in systems that are used broadly by the Intenet community and help close those gaps before they can be exploited. PGP Security does not provide the patches, but it sells a risk assessment product called CyberCop Scanner, which has been updated to detect the latest vulnerability.