Source: https://www.owasp.org
OWASP is an international organization that specifies the top 10 vulnerabilities and flaws of web applications. The latest OWASP top 10 application security risks are as follows:
A1 – Injection
Injection flaws, such as SQL, command injection, 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 authorization.
A2 – Broken Authentication
Application functions related to authentication and session management are often implemented incorrectly, thereby allowing attackers to compromise passwords, keys, or session tokens or to exploit other implementation flaws to assume identities of other users (temporarily or permanently).
A3 – Sensitive Data Exposure
Many web applications and APIs do not properly protect sensitive data, such as financial, healthcare, and personally identifiable information (PII) data. Attackers may steal or modify such weakly protected data to conduct credit card fraud, identity theft, or other crimes. Sensitive data requires extra protection such as encryption at rest or in transit, as well as special precautions when exchanged with the browser.
A4 – XML External Entity (XXE)
Many older or poorly configured XML processors evaluate external entity references within XML documents. External entities can disclose internal files using the file URI handler, internal SMB file shares on unpatched Windows servers, internal port scanning, remote code execution, and DoS service attacks such as the billion laughs attack.
A5 – Broken Access Control
Restrictions on what authenticated users are allowed to do are not properly enforced. Attackers can exploit these flaws to access unauthorized functionality and/or data, such as accessing other users' accounts, viewing sensitive files, modifying other users’ data, and changing access rights.
A6 – Security Misconfiguration
Security misconfiguration is the most common issue in web security, which is due in part to manual or ad hoc configuration (or no configuration at all), insecure default configurations, open S3 buckets, misconfigured HTTP headers, error messages containing sensitive information, and not patching or upgrading systems, frameworks, dependencies, and components in a timely manner (or at all).
A7 – Cross-Site Scripting (XSS)
XSS flaws occur whenever an application includes untrusted data in a new web page without proper validation or escaping, or whenever it updates an existing web page with user-supplied data using a browser API that can create JavaScript. XSS allows attackers to execute scripts in the victim’s browser, which can hijack user sessions, deface websites, or redirect the user to malicious sites.
A8 – Insecure Deserialization
Insecure deserialization flaws occur when an application receives hostile serialized objects. Insecure deserialization leads to remote code execution. Even if deserialization flaws do not result in remote code execution, serialized objects can be replayed, tampered with, or deleted to spoof users, conduct injection attacks, and elevate privileges.
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 defenses and enable various attacks and impacts.
A10 – Insufficient Logging and Monitoring
Insufficient logging and monitoring, coupled with missing or ineffective integration with incident response, allows attackers to further attack systems, maintain persistence, pivot to more systems, and tamper with, extract, or destroy data. Most breach studies show that the time to detect a breach is over 200 days, typically by external parties rather than internal processes or monitoring.