Focus on Top 10 Most Critical Web Application Security Risk

Forward

Insecure software is already undermining our financial, healthcare, defense, energy, and other critical infrastructure. As our digital infrastructure gets increasingly complex and interconnected, the difficulty of achieving application security increases exponentially. We can no longer afford to tolerate relatively simple security problems like those presented in the OWASP Top 10.

The goal of the Top 10 project is to raise awareness about application security by identifying some of the most critical risks facing organizations. The Top 10 project is referenced by many standards, books, tools, and organizations, including MITRE, PCI DSS, DISA, FTC, and many more. This release of the OWASP Top 10 marks this project’s eighth year of raising awareness of the importance of application security risks. The OWASP Top 10 was first released in 2003, minor updates were made in 2004 and 2007, and this is the 2010 release.

We encourage you to use the Top 10 to get your organization started with application security. Developers can learn from the mistakes of other organizations. Executives should start thinking about how to manage the risk that software applications create in their enterprise.

But the Top 10 is not an application security program. Going forward, OWASP recommends that organizations establish a strong foundation of training, standards, and tools that makes secure coding possible. On top of that foundation, organizations should integrate security into their development, verification, and maintenance processes. Management can use the data generated by these activities to manage cost and risk associated with application security.

We hope that the OWASP Top 10 is useful to your application security efforts. Please don’t hesitate to contact OWASP with your questions, comments, and ideas, either publicly to OWASP-TopTen@lists.owasp.org or privately to dave.wichers@owasp.org.

Welcome

Welcome to the OWASP Top 10 2010! This significant update presents a more concise, risk focused list of the Top 10 Most Critical Web Application Security Risks. The OWASP Top 10 has always been about risk, but this update makes this much more clear than previous editions. It also provides additional information on how to assess these risks for your applications.

For each item in the top 10, this release discusses the general likelihood and consequence factors that are used to categorize the typical severity of the risk. It then presents guidance on how to verify whether you have problems in this area, how to avoid them, some example flaws, and pointers to links with more information.

The primary aim of the OWASP Top 10 is to educate developers, designers, architects, managers, and organizations about the consequences of the most important web application security weaknesses. The Top 10 provides basic techniques to protect against these high risk problem areas – and also provides guidance on where to go from here.

Warnings

Don’t stop at 10. There are hundreds of issues that could affect the overall security of a web application as discussed in the OWASP Developer’s Guide. This is essential reading for anyone developing web applications today. Guidance on how to effectively find vulnerabilities in web applications are provided in the OWASP Testing Guide and the OWASP Code Review Guide, which have both been significantly updated since the previous release of the OWASP Top 10.

Constant change. This Top 10 will continue to change. Even without changing a single line of your application’s code, you may already be vulnerable to something nobody ever thought of before. Please review the advice at the end of the Top 10 in “What’s Next For Developers, Verifiers, and Organizations” for more information.

Think positive. When you’re ready to stop chasing vulnerabilities and focus on establishing strong application security controls, OWASP has just produced the Application Security Verification Standard (ASVS) as a guide to organizations and application reviewers on what to verify. Use tools wisely. Security vulnerabilities can be quite complex and buried in mountains of code. In virtually all cases, the most cost-effective approach for finding and eliminating these weaknesses is human experts armed with good tools.

Push left. Secure web applications are only possible when a secure software development life-cycle is used. For guidance on how to implement a secure SDLC, we recently released the Open Software Assurance Maturity Model (SAMM), which is a major update to the OWASP CLASP Project.

What Are Application Security Risks?

Attackers can potentially use many different paths through your application to do harm to your business or organization. Each of these paths represents a risk that may, or may not, be serious enough to warrant attention.

Sometimes, these paths are trivial to find and exploit and sometimes they are extremely difficult. Similarly, the harm that is caused may range from nothing, all the way through putting you out of business. To determine the risk to your organization, you can evaluate the likelihood associated with each threat agent, attack vector, and security weakness and combine it with an estimate of the technical and business impact to your organization. Together, these factors determine the overall risk.

What’s My Risk?

This update to the OWASP Top 10 focuses on identifying the most serious risks for a broad array of organizations. For each of these risks, we provide generic information about likelihood and technical impact using the following simple ratings scheme, which is based on the OWASP Risk Rating Methodology.

Threat Agent	Attack Vector	Weakness Prevalence	Weakness Detectability	Technical Impact	Business Impact
?	Easy	Widespread	Easy	Severe	?
?	Average	Common	Average	Moderate	?
?	Difficult	Uncommon	Difficult	Minor	?

However, only you know the specifics of your environment and your business. For any given application, there may not be a threat agent that can perform the relevant attack, or the technical impact may not make any difference. Therefore, you should evaluate each risk for yourself, focusing on the threat agents, security controls, and business impacts in your enterprise.

Although previous versions of the OWASP Top 10 focused on identifying the most common “vulnerabilities”, they were also designed around risk. The names of the risks in the Top 10 stem from the type of attack, the type of weakness, or the type of impact they cause. We chose the name that is best known and will achieve the highest level of awareness.

OWASP Top 10 Application Security Risks – 2010

A1-Injection	Injection flaws, such as SQL, OS, and LDAP injection, occur when untrusted data is sent to an interpreter as part of a command or query. The attacker’s hostile data can trick the interpreter into executing unintended commands or accessing unauthorized data.
A2-Cross Site Scripting (XSS)	XSS flaws occur whenever an application takes untrusted data and sends it to a web browser without proper validation and escaping. XSS allows attackers to execute scripts in the victim’s browser which can hijack user sessions, deface web sites, or redirect the user to malicious sites.
A3-Broken Authentication and Session Management	Application functions related to authentication and session management are often not implemented correctly, allowing attackers to compromise passwords, keys, session tokens, or exploit other implementation flaws to assume other users’ identities.
A4-Insecure Direct Object References	A direct object reference occurs when a developer exposes a reference to an internal implementation object, such as a file, directory, or database key. Without an access control check or other protection, attackers can manipulate these references to access unauthorized data.
A5-Cross Site Request Forgery (CSRF)	A CSRF attack forces a logged-on victim’s browser to send a forged HTTP request, including the victim’s session cookie and any other automatically included authentication information, to a vulnerable web application. This allows the attacker to force the victim’s browser to generate requests the vulnerable application thinks are legitimate requests from the victim.
A6-Security Misconfiguration	Good security requires having a secure configuration defined and deployed for the application, frameworks, application server, web server, database server, and platform. All these settings should be defined, implemented, and maintained as many are not shipped with secure defaults. This includes keeping all software up to date, including all code libraries used by the application.
A7-Insecure Cryptographic Storage	Many web applications do not properly protect sensitive data, such as credit cards, SSNs, and authentication credentials, with appropriate encryption or hashing. Attackers may steal or modify such weakly protected data to conduct identity theft, credit card fraud, or other crimes.
A8-Failure to Restrict URL Access	Many web applications check URL access rights before rendering protected links and buttons. However, applications need to perform similar access control checks each time these pages are accessed, or attackers will be able to forge URLs to access these hidden pages anyway.
A9-Insufficient Transport Layer Protection	Applications frequently fail to authenticate, encrypt, and protect the confidentiality and integrity of sensitive network traffic. When they do, they sometimes support weak algorithms, use expired or invalid certificates, or do not use them correctly.
A10-Unvalidated Redirects and Forwards	Web applications frequently redirect and forward users to other pages and websites, and use untrusted data to determine the destination pages. Without proper validation, attackers can redirect victims to phishing or malware sites, or use forwards to access unauthorized pages.