How Hackers Attack

There are many types of attacks that a hacker can initiate against an unsecured system. Some of these attacks can be stopped by a firewall but some are only preventable by monitoring attack attempts on your server and making adjustments to your security as necessary. The following list is a summary of the types of attacks that be waged against your server:

• Remote Log On: This attack occurs when someone logs on to your server and uses its resources or programs (including files and data). Hackers sometimes use this method to attack another network using your server as the offending source.
• Denial of Service: In this attack, the hacker sends a request to connect to a unsuspecting server. When the server attempts to respond and connect, it cannot find the requesting server. By sending repeated requests, the hacker can bog down the server and eventually cause it to crash.
• Viruses: A virus is a small program that spreads from computer to computer, erasing files or crashing entire systems. Some viruses simply manipulate the data on the system while others are more destructive and completely erase all data in the system.
• Application Backdoors: Some programs have a "backdoor" that allows someone to gain access and use their resources. While some programs have a backdoor built into them on purpose, some programs contain bugs that provide a backdoor.
• Operating System Bugs: Similar to the application backdoor attack, this attack uses vulnerabilities in your operating system to gain access to your server and use its resources.
• SMTP Session Hijacking: Simple Mail Transfer Protocol (SMTP) is a method of sending email. Hackers can use your server to send unsolicited email (also know as spam) to thousands of email addresses. This means that your server address will be shown as the sender when in fact it was not you who sent the email.
• Spam: Spam is the electronic version of the junk mail you receive in your mailbox. Most of the time spam is harmless, but occasionally hackers use spam to entice you to click a link that places a cookie on your system that provides a backdoor to your system. This is why many security experts warn against clicking links in unsolicited email.
• Email Bombs: These attacks are often personal in nature as they send the same email (sometimes thousands of copies) to a specific email address until the receiving system can no longer receive any other email.
• Redirect Bombs: Using Internet Control Message Protocol (ICMP) hackers can redirect data and send it using a different router. This is often used when creating a denial of service attack.
• Macros: Many programs allow you to create a macro or "script" of actions to perform complicated or lengthy procedures. Macros are helpful in that they allow you to perform several tasks. Hackers can create their own macros to erase or destroy data, or crash your computer.
• Source Routing: Data packets travel through the Internet using routers along the way to specify its path. Hackers can make data appear as if it comes from within the network (or from your server) when in fact it is coming from a possibly dangerous source.