Federal flaw database commits to grading system

Some software makers worry that rating vulnerabilities could have some legal implications. For example, if a company gave a flaw a low rating and then that issue was used as an avenue for a costly attack, the firm could be held liable for its severity ranking. Such worries have caused companies to take their time debating the merits of adopting the Common Vulnerability Scoring System, said Gavin Reid, team lead for the CVSS program at the Forum of Incident Response and Security Teams (FIRST), which was chosen to host the CVSS project.

"I think there is significant hurdles for people adopting the scoring system," said Reid, who also works for Cisco, one of the companies that supported the creation of the CVSS. "But once one or two of them start using it, I think we will see a lot more adopting CVSS."

For that reason, the National Vulnerability Database's decision to use the scoring system and the group's ranking of more than 13,000 previous vulnerabilities has given CVSS a major boost, Reid said.

The NVD is managed by National Institute of Standards and Technology (NIST) but funded through the Department of Homeland Security. The group's staff adds 16 new vulnerabilities to the the database each day, up from 8 per day in August, and keeps a variety of current statistics, including a measure of the workload that the release of such flaws has on network administrators.

The National Vulnerability Database (NVD) is an initiative funded by the US Department of Homeland Security to boost the preparedness of the nation's Internet and computer infrastructure, as called for by the Bush Administration's National Strategy to Secure Cyberspace. Other DHS initiatives, such as the US Computer Emergency Readiness Team (US-CERT), release some information on serious vulnerabilities, but do not try to create a complete collection of critical and non-critical flaws.

The NVD piggybacks on the Common Vulnerability and Exposures (CVE) to do just that. The CVE, a listing of serious vulnerabilities maintained by the Mitre Corporation, expands on the Internet Catalog (ICAT)--a previous NIST project--that archived the vulnerabilities defined by the Common Vulnerability and Exposures list.

The NVD team scored the vulnerabilities using an automated process. The CVE database only had about 80 percent of the information needed to give an exact score, Mell said, so the group has generated the scores based on the information at hand and labeled each one "approximate."

The CVE definitions are one of the standards that the National Vulnerability Database depends on. The database also uses the Open Vulnerability and Assessment Language (OVAL) to describe the security issues in a standard language, NIST's Mell said.

"The reason we chose CVSS as opposed to another scoring system was that we believe in standards," Mell said. "If everyone uses a different scoring system, then the effectiveness of each scoring system is limited."

Currently, the database gets nearly 1.5 million hits a month from the private sector as well as government and academic users, Mell said. The group also provides a calculator for companies to generate an environmental score based on the vulnerable systems and the company's use of those systems.

Copyright © 2005, SecurityFocus

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