VRT Rules 2013-10-15
Sourcefire VRT Rules Update
This release contains updated base policies and also adds and modifies rules in several categories.
This SEU/SRU contains updated base policies for use in your Sourcefire devices.
To help customers understand these changes, we are taking this opportunity to explain the process used by the VRT for deciding how rules are assigned to each policy.
The main metric used is the CVSS score assigned to each vulnerability that might be covered by a rule. For more information on CVSS please visit http://www.first.org/cvss. The second criteria is temporal-based and concerns the age of a particular vulnerability. The final criteria is the particular area of coverage for the rule. So for example, SQL Injection rules are considered to be important enough to have influence when being considered for policy inclusion. Note that, the vulnerabilities covered by the rules in these categories are considered important regardless of age.
The considerations for each policy are described below.
Connectivity over Security Base Policy:
1. CVSS Score must be 10 2. Age of the vulnerability: Current year (2013 for example) Last year (2012 in this example) Year before last (2011 in this example) 3. Rule Category Not used for this policy
Balanced Base Policy:
1. CVSS Score 9 or greater 2. Age of the vulnerability: Current year (2013 for example) Last year (2012 in this example) Year before last (2011 in this example) 3. Rule Category Malware-Cnc Blacklist SQL Injection Exploit-kit
Security over Connectivity Base Policy:
1. CVSS Score 8 or greater 2. Age of the vulnerability: Current year (2013 for example) Last year (2012 in this example) Year before last (2011 in this example) Year prior (2010 in this example) 3. Rule Category Malware-Cnc Blacklist SQL Injection Exploit-kit App-detect
All new rules are placed into the policies based on these criteria. Every year during the third quarter of the year, the policies will be re-assessed and rules from previous years, as the vulnerabilities age, will be removed from the policy to keep the policy compliant with our temporal selection criteria. Thus, in the third quarter of 2014, the rules from 2011 will be removed from the “Connectivity over Security” and “Balanced” policies while the rules from 2010 will be removed from the “Security over Connectivity” policy. If rules move between categories, their presence in policies will also be decided based on the category selection process. Likewise, should the CVSS score change for a particular vulnerability that is covered by a rule, its presence in a policy based on the CVSS metric is also re-assessed.
Rules in the listed policies are evaluated on a rule by rule basis.
Policies that will be affected:
Those policies that create or have created a policy based on one of the Sourcefire base policies. Those policies that have not modified any of the rule states manually.
The Sourcefire VRT has also added and modified multiple rules in the blacklist, browser-chrome, browser-firefox, browser-ie, browser-other, browser-plugins, browser-webkit, content-replace, exploit-kit, file-executable, file-flash, file-identify, file-image, file-java, file-multimedia, file-office, file-other, file-pdf, indicator-compromise, indicator-obfuscation, indicator-scan, indicator-shellcode, malware-cnc, netbios, os-linux, os-mobile, os-other, os-solaris, os-windows, policy-other, policy-social, policy-spam, protocol-dns, protocol-ftp, protocol-icmp, protocol-imap, protocol-nntp, protocol-rpc, protocol-scada, protocol-services, protocol-snmp, protocol-telnet, protocol-tftp, protocol-voip, pua-adware, pua-other, pua-p2p, pua-toolbars, server-apache, server-iis, server-mail, server-mssql, server-mysql, server-oracle, server-other and server-webapp rule sets to provide coverage for emerging threats from these technologies.
Rule Pack Summary:
For a complete list of new and modified rules, click here.
Sourcefire VRT rule packs often utilize enhancements made to Snort. Operators should upgrade to the latest revision or patch level for Snort to ensure these enhancements are available before using these rules.
About the VRT:
The Sourcefire VRT is a group of leading edge intrusion detection and prevention experts working to proactively discover, assess and respond to the latest trends in hacking activity, intrusion attempts and vulnerabilities. This team is also supported by the vast resources of the open source Snort community, making it the largest group dedicated to advances in the network security industry.why subscribe? || download rules