Job Study

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Job Study
2011-12-05 16:59:55

Studying for job
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  1. What is observer pattern?
    The Observer Pattern defines a one-to-many dependency between objects so that when one objecct changes state, all of its dependents are notified and updated automatically.
  2. What is the difference between an Interface and an Abstract class?
    An abstract class can have instance methods that implement a default behavior. An Interface can only declare constants and instance methods, but cannot implement default behavior and all methods are implicitly abstract.

    An interface has all public members and no implementation. An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.
  3. What are synchronized methods and synchronized
    Synchronized methods are methods that are used to control access to an object. A thread only executes a synchronized method after it has acquired the lock for the method's object or class. Synchronized statements are similar to synchronized methods. A synchronized statement can only be executed after a thread has acquired the lock for the object or class referenced in the synchronized statement.
  4. What does it mean that a method or field
    is "static"?
    1. Static variables and methods are instantiated only once per class.

    2. If you change the value of a static variable in a particular object, the value of that variable changes for all instances of that class.

    3. Static methods can be referenced with the name of the class rather than the name of a particular object of the class.
  5. What is the difference between preemptive scheduling and time slicing?
    Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead states or a higher priority task comes into existence.

    Under time slicing, a task executes for a predefined slice of time and then reenters the pool of ready tasks. The scheduler then determines which task should execute next, based on priority and other factors.
  6. What is decorator pattern?
    The Decorator Pattern attaches additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extedning functionality.
  7. What is 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.
  8. What is 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.
  9. What is "Broken Authentication and Session Management" in OWASP 2010 Top Ten?
    ´╗┐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.
  10. Define 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.
  11. Define 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.
  12. What is "Security Misconfiguration" in OWASP 2010 Top Ten?
    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.
  13. What is "Insecure Cryptographic Storage" in OWASP 2010 Top Ten?
    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.
  14. What is "Failure to Restrict URL Access" in OWASP 2010 Top Ten?
    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.
  15. What is "Insufficient Transport Layer Protection" in OWASP 2010 Top Ten?
    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.
  16. What is "Unvalidated Redirects and Forwards" in OWASP 2010 Top Ten?
    • 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.