Some attack techniques- Hacking

-By

Nitin Kumar Verma

MSCLIS(2007-2009), IIIT-Allahabad

Cross-Site Scripting (XSS)

Websites today are more complex than ever, containing a lot of dynamic content making the experience for the user more enjoyable. Dynamic websites suffer from a threat that static websites don't, called "Cross Site Scripting". Cross site scripting (also known as XSS) occurs when a web application gathers malicious data from a user. This allows an attacker to embed malicious JavaScript into the generated page, allowing the attacker to execute script on the machine of any user that views the malicious page. Any site that allows users to post text messages can be vulnerable to an attack such as this.
example: PayPal was targeted when attackers redirected PayPal visitors to a page warning users their accounts had been compromised. Victims were redirected to a phishing site and prompted to enter PayPal login information, Social Security numbers and credit card details. PayPal said it closed the vulnerability in June 2006.

DoS attack

 
A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users. In a denial of service attack, the user sends several authentication requests to the server, filling it up. All requests have false return addresses, so the server can't find the user when it tries to send the authentication approval. The server waits, sometimes more than a minute, before closing the connection. When it does close the connection, the attacker sends a new batch of forged requests, and the process begins again--tying up the service indefinitely.

Cookie Manipulation

Many Web applications use cookies to save information (for example, user ID's and timestamps) on the client's machine. Often, cookies are not securely encoded, allowing a hacker to modify them. By changing these values, or "poisoning" the cookie, malicious users can gain access to the accounts and information of other users. As well, attackers can also steal a user's cookie and gain direct access to the user's account, bypassing the need to enter an ID and password or other form of authentication.

Broken authentication and session management

Flaws in the main authentication mechanism are not uncommon, but weaknesses are more often introduced through ancillary authentication functions such as logout, password management, timeout, remember me, secret question and account update.
User and administrative accounts can be hijacked when applications fail to protect credentials and session tokens from beginning to end. Watch out for privacy violations and the undermining of authorization and accountability controls.
Example: Microsoft had to eliminate a vulnerability in Hotmail that could have let malicious JavaScript programmers steal user passwords in 2002. Revealed by a networking products reseller, the flaw was vulnerable to e-mails containing Trojans that altered the Hotmail user interface, forcing users to repeatedly reenter their passwords and unwittingly send them to hackers.

Injection flaws

When user-supplied data is sent to interpreters as part of a command or query, hackers trick the interpreter which interprets text-based commands into executing unintended commands. Injection flaws allow attackers to create, read, update, or delete any arbitrary data available to the application, OWASP writes. In the worst-case scenario, these flaws allow an attacker to completely compromise the application and the underlying systems, even bypassing deeply nested firewalled environments.
Example: Russian hackers broke into a Rhode Island government Web site to steal credit card data in January 2006. Hackers claimed the SQL injection attack stole 53,000 credit card numbers, while the hosting service provider claims it was only 4,113.