The last few days I have looked at ways to track open security +issues here at my work with the University of Oslo. My idea is that +it should be possible to use the information about security issues +available on the Internet, and check our locally +maintained/distributed software against this information. It should +allow us to verify that no known security issues are forgotten. The +CVE database listing vulnerabilities seem like a great central point, +and by using the package lists from Debian mapped to CVEs provided by +the testing security team, I believed it should be possible to figure +out which security holes were present in our free software +collection.
+ +After reading up on the topic, it became obvious that the first +building block is to be able to name software packages in a unique and +consistent way across data sources. I considered several ways to do +this, for example coming up with my own naming scheme like using URLs +to project home pages or URLs to the Freshmeat entries, or using some +existing naming scheme. And it seem like I am not the first one to +come across this problem, as MITRE already proposed and implemented a +solution. Enter the Common +Platform Enumeration dictionary, a vocabulary for referring to +software, hardware and other platform components. The CPE ids are +mapped to CVEs in the National +Vulnerability Database, allowing me to look up know security +issues for any CPE name. With this in place, all I need to do is to +locate the CPE id for the software packages we use at the university. +This is fairly trivial (I google for 'cve cpe $package' and check the +NVD entry if a CVE for the package exist).
+ +To give you an example. The GNU gzip source package have the CPE +name cpe:/a:gnu:gzip. If the old version 1.3.3 was the package to +check out, one could look up +cpe:/a:gnu:gzip:1.3.3 +in NVD and get a list of 6 security holes with public CVE entries. +The most recent one is +CVE-2010-0001, +and at the bottom of the NVD page for this vulnerability the complete +list of affected versions is provided.
+ +The NVD database of CVEs is also available as a XML dump, allowing +for offline processing of issues. Using this dump, I've written a +small script taking a list of CPEs as input and list all CVEs +affecting the packages represented by these CPEs. One give it CPEs +with version numbers as specified above and get a list of open +security issues out.
+ +Of course for this approach to be useful, the quality of the NVD +information need to be high. For that to happen, I believe as many as +possible need to use and contribute to the NVD database. I notice +RHEL is providing +a +map from CVE to CPE, indicating that they are using the CPE +information. I'm not aware of Debian and Ubuntu doing the same.
+ +To get an idea about the quality for free software, I spent some +time making it possible to compare the CVE database from Debian with +the CVE database in NVD. The result look fairly good, but there are +some inconsistencies in NVD (same software package having several +CPEs), and some inaccuracies (NVD not mentioning buggy packages that +Debian believe are affected by a CVE). Hope to find time to improve +the quality of NVD, but that require being able to get in touch with +someone maintaining it. So far my three emails with questions and +corrections have not seen any reply, but I hope contact can be +established soon.
+ +An interesting application for CPEs is cross platform package +mapping. It would be useful to know which packages in for example +RHEL, OpenSuSe and Mandriva are missing from Debian and Ubuntu, and +this would be trivial if all linux distributions provided CPE entries +for their packages.
+ +