By Robert Lemos
9th January 2006
After three years of modest or no gains, the number of publicly
reported vulnerabilities jumped in 2005, boosted by easy-to-find bugs
in web applications. Yet, questions remain about the value of
analyzing current databases, whose data rarely correlates easily.
A survey of four major vulnerability databases found that the number
of flaws counted by each in the past five years differed
significantly. However, three of the four databases exhibited a
relative plateau in the number of flaws publicly disclosed in 2002
through 2004. And, every database saw a significant increase in their
count of the flaws disclosed in 2005.
A few common themes emerged from the data as well. In 2005,
easy-to-find flaws in web applications were likely responsible for the
majority of the increase, the database managers said in interviews
with SecurityFocus. However, some of the increase came from a doubling
in the number of flaws released by large software companies.
The most important, and perhaps obvious, lesson is that the software
flaws are here to stay, said Peter Mell, a senior computer scientist
for the National Institute of Standards and Technology (NIST) and the
creator of the National Vulnerability Database (NVD) , one of the
four databases surveyed.
"The problem of people breaking into computers is not going away any
time soon," Mell said. "There is certainly more patches every year
that system administrators need to install, but the caveat is that
more vulnerabilities seem to apply to less important software."
Vulnerability databases are coming of age. In 2005, NIST created the
National Vulnerability Database  and software makers and security
service providers have cooperated to create the Common Vulnerability
Scoring System (CVSS) , a standardized measure of the severity of
software flaws. The National Vulnerability Database completed scoring
flaws  in its database using the CVSS in late November. While
auctions of vulnerability research have not taken off , two
companies now buy vulnerability information  from flaw finders.
Four databases were surveyed: The Computer Emergency Response Team
(CERT) Coordination Center's database, the National Vulnerability
Database (NVD), the Open-Source Vulnerability Database (OSVDB), and
the Symantec Vulnerability Database. (SecurityFocus is owned by
The number of flaws cataloged by each database in 2005 varied widely,
because of differing definitions of what constitutes a vulnerability
and differing editorial policy. The OSVDB  - which counted the
highest number of flaws in 2005 at 7,187 - breaks down vulnerabilities
into their component parts, so what another database might classify as
one flaw might be assigned multiple entries. SecurityFocus  had the
lowest count of the vulnerabilities at 3,766.
The variations in editorial policy and lack of cross-referencing
between databases as well as unmeasurable biases in the research
community and disclosure policy mean that the databases - or refined
vulnerability information (RVI) sources - do not produce statistics
that can be meaningfully compared, Steve Christey, the editor of the
Common Vulnerability and Exposures (CVE) , wrote in an e-mail to
security mailing lists  on Thursday. The CVE is a dictionary of
security issues compiled by The MITRE Corp., a government contractor
and nonprofit organization.
"In my opinion, RVI sources are still a year or two away from being
able to produce reliable, repeatable, and comparable statistics," he
wrote. "In general, consumers should treat current statistics as
suggestive, not conclusive."
Recent numbers produced by the U.S. Computer Emergency Readiness Team
(US-CERT) revealed some of the problems with refined vulnerability
sources. Managed by the CERT Coordination Center, the US-CERT's
security bulletins outline security issues but are updated each week.
In a year end list published last week, the US-CERT announced that
5,198 vulnerabilities had been reported in 2005. Some mainstream media
outlets noted the number , compared it to the CERT Coordination
Center's previous data - which is compiled from a different set of
vulnerability reports - and concluded there was a 38 per cent increase
in vulnerabilities in 2005 over the previous year.
In fact, discounting the updated reports resulted in a 41 per cent
decrease to 3,074 vulnerabilities, according to an analysis done by
Alan Wylie, an independent computer programmer. If the data point
could be compared with statistics from CERT/CC, that would have placed
the number of flaws reported in line with the previous three years.
Yet, while the data is significantly flawed, the original story told
by US-CERT's list seems to be the right one. The number of
vulnerabilities reported in 2005 increased, mainly due to researchers
looking into the security of Web applications. The National
Vulnerability Database noted the largest increase of 96 percent from
2004 to 2005, while the Symantec Vulnerability Database saw the
smallest increase of 40 percent.
While publicly reported flaws jumped, that does not necessarily mean
dire prospects for home users' or businesses' security, said David
Ahmad, manager for development at Symantec's Security Response team.
"Web-based vulnerabilities are all over the place and they are really
easy to find--they are the low-hanging fruit," Ahmad said." We have
had high-profile vulnerabilities, but that is not what is driving this
Finding those flaws does not require much skills, said Brian Martin,
content manager for the OSVDB.
"We are seeing people discover vulnerabilities in software with tiny
distribution and low installed base--free guestbooks that are written
left and right, available by the thousands," he said. "And we are
seeing that it takes no skill to find vulnerabilities in these
The number of vulnerabilities entered into four major databases vary
widely over the past five years, but seem to indicate that 2005 was a
banner year for bugs.
2005 2004 2003 2002 2001
CERT/CC 5,990 3,780 3,784 4,129 2,437
NVD 4,584 2,340 1,248 1,943 1,672
OSVDB 7,187 4,629 2,632 2,184 1,656
Symantec 3,766 2,691 2,676 2,604 1,472
Sources: Computer Emergency Response Team Coordination Center
(CERT/CC), National Vulnerability Database, Open-Source Vulnerability
Database, and the Symantec Vulnerability Database.
Yet, the entire focus should not be on the rash of Web application
flaws, Mell said.
The computer scientist conducted an informal survey of entries for
flaws in products from well-known companies and found that six of 14
software makers had seen a doubling in the number of vulnerability
reports, while another four firms saw a decrease in the number of
reports. The remaining four companies reported a similar number of
flaws as the year before.
"I find it amazing that large and reputable software companies are
seeing a large number more flaws this year (2005) than last year,"
The database managers also cautioned that the vulnerability counts for
any particular year generally do not reflect the state of secure
software development, only where the research community's interests
"These numbers are showing the state of practice from a few years ago,
rather than what the current state of practice is today," said Jeff
Havrilla, team leader of vulnerability analysis at the CERT
Making the issue more difficult, several software vendors move to
release patches on a specific day has resulted in most security
bulletins detailing multiple vulnerabilities, a situation that makes
the true number of flaws harder to count, Havrilla said.
This article was originally published at SecurityFocus .
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