The Open Web Application Security Project (OWASP) is dedicated to helping organizations understand and improve the security of their web applications and web services. They released their list of top 10 vulnerabilities in web applications:

• Unvalidated Parameters - Information from web requests is not validated before being used by a web application. Attackers can use these flaws to attack backside components through a web application.
• Broken Access Control - Restrictions on what authenticated users are allowed to do are not properly enforced. Attackers can exploit these flaws to access other users’ accounts, view sensitive files, or use unauthorized functions.
• Broken Account and Session Management - Account credentials and session tokens are not properly protected. Attackers that can compromise passwords, keys, session cookies, or other tokens can defeat authentication restrictions and assume other users’ identities.
• Cross-Site Scripting (XSS) Flaws - The web application can be used as a mechanism to transport an attack to an end user’s browser. A successful attack can disclose the end user’s session token, attack the local machine, or spoof content to fool the user.
• Buffer Overflows - Web application components in some languages that do not properly validate input can be crashed and, in some cases, used to take control of a process. These components can include CGI, libraries, drivers, and web application server components.
• Command Injection Flaws - Web applications pass parameters when they access external systems or the local operating system. If an attacker can embed malicious commands in these parameters, the external system may execute those commands on behalf of the web application.
• Error Handling Problems - Error conditions that occur during normal operation are not handled properly. If an attacker can cause errors to occur that the web application does not handle, they can gain detailed system information, deny service, cause security mechanisms to fail, or crash the server.
• Insecure Use of Cryptography - Web applications frequently use cryptographic functions to protect information and credentials. These functions and the code to integrate them have proven difficult to code properly, frequently resulting in weak protection.
• Remote Administration Flaws - Many web applications allow administrators to access the site using a web interface. If these administrative functions are not very carefully protected, an attacker can gain full access to all aspects of a site.
• Web and Application Server Misconfiguration - Having a strong server configuration standard is critical to a secure web application. These servers have many configuration options that affect security and are not secure out of the box.

This list was created to focus government and industry on the most serious of these vulnerabilities. Web application security vulnerabilities are highly exploitable and the consequence of an attack can be devastating. These vulnerabilities represent an equivalent magnitude of risk as network security problems, and should be given the same degree of attention.


The complete PDF report with details of each vulnerability can be downloaded here.