The OWASP Top 10 for 2017 is based primarily on 11 large datasets from firms that specialise in application security, including 8 consulting companies and 3 product vendors. This data spans vulnerabilities gathered from hundreds of organisations and over 50,000 real-world applications and APIs. The Top 10 items are selected and prioritised according to this prevalence data, in combination with consensus estimates of exploitability, detectability, and impact.
The primary aim of the OWASP Top 10 is to educate developers, designers, architects, managers, and organisations 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.
A1 – Injection
Injection flaws, such as SQL, OS, XXE, 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 data without proper authorisation.
A2 – Broken Authentication and Session Management
Application functions related to authentication and session management are often implemented incorrectly, allowing attackers to compromise passwords, keys, or session tokens, or to exploit other implementation flaws to assume other users’ identities (temporarily or permanently).
A3 – Cross-Site Scripting (XSS)
A4 – Broken Access Control
Restrictions on what authenticated users are allowed to do are not properly enforced. Attackers can exploit these flaws to access unauthorised functionality and/or data, such as access other users’ accounts, view sensitive files, modify other users’ data, change access rights, etc.
A5 – Security Misconfiguration
Good security requires having a secure configuration defined and deployed for the application, frameworks, application server, web server, database server, platform, etc. Secure settings should be defined, implemented, and maintained, as defaults are often insecure. Additionally, software should be kept up to date.
A6 – Sensitive Data Exposure
Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare, and PII. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data deserves extra protection such as encryption at rest or in transit, as well as special precautions when exchanged with the browser.
A7 – Insufficient Attack Protection
The majority of applications and APIs lack the basic ability to detect, prevent, and respond to both manual and automated attacks. Attack protection goes far beyond basic input validation and involves automatically detecting, logging, responding, and even blocking exploit attempts. Application owners also need to be able to deploy patches quickly to protect against attacks.
A8 – Cross-Site Request Forgery
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. Such an attack allows the attacker to force a victim’s browser to generate requests the vulnerable application thinks are legitimate requests from the victim.
A9 – Using Components with Known Vulnerabilities
Components, such as libraries, frameworks, and other software modules, run with the same privileges as the application. If a vulnerable component is exploited, such an attack can facilitate serious data loss or server takeover. Applications and APIs using components with known vulnerabilities may undermine application defences and enable various attacks and impacts.
A10 – Under-protected APIs