2011 CWE/SANS Top 25 Most Dangerous Software Errors

The 2011 CWE/SANS Top 25 Most Dangerous Software Errors is a list of the most widespread and critical errors that can lead to serious vulnerabilities in software. They are often easy to find, and easy to exploit. They are dangerous because they will frequently allow attackers to completely take over the software, steal data, or prevent the software from working at all.

The Top 25 list is a tool for education and awareness to help programmers to prevent the kinds of vulnerabilities that plague the software industry, by identifying and avoiding all-too-common mistakes that occur before software is even shipped. Software customers can use the same list to help them to ask for more secure software. Researchers in software security can use the Top 25 to focus on a narrow but important subset of all known security weaknesses. Finally, software managers and CIOs can use the Top 25 list as a measuring stick of progress in their efforts to secure their software.

The list is the result of collaboration between the SANS Institute, MITRE, and many top software security experts in the US and Europe. It leverages experiences in the development of the SANS Top 20 attack vectors (http://www.sans.org/top20/) and MITRE's Common Weakness Enumeration (CWE) (http://cwe.mitre.org/). MITRE maintains the CWE web site, with the support of the US Department of Homeland Security's National Cyber Security Division, presenting detailed descriptions of the top 25 programming errors along with authoritative guidance for mitigating and avoiding them. The CWE site contains data on more than 800 programming errors, design errors, and architecture errors that can lead to exploitable vulnerabilities.

The 2011 Top 25 makes improvements to the 2010 list, but the spirit and goals remain the same. This year's Top 25 entries are prioritized using inputs from over 20 different organizations, who evaluated each weakness based on prevalence, importance, and likelihood of exploit. It uses the Common Weakness Scoring System (CWSS) to score and rank the final results. The Top 25 list covers a small set of the most effective "Monster Mitigations," which help developers to reduce or eliminate entire groups of the Top 25 weaknesses, as well as many of the hundreds of weaknesses that are documented by CWE.