t’s one thing to know generally that your systems are under fire from hackers around the world and malicious users around the office; it’s another to understand the specific attacks against your systems that are possible. This section discusses some well-known attacks but is by no means a comprehensive listing.
Many security vulnerabilities aren’t critical by themselves. However, exploiting several vulnerabilities at the same time can take its toll on a system or network environment. For example, a default Windows OS configuration, a weak SQL Server administrator password, or a server hosted on a wireless network might not be major security concerns by themselves — but someone exploiting all three of these vulnerabilities at the same time could lead to sensitive information disclosure and more.
Exploits that involve manipulating people — end users and even yourself — are the greatest vulnerability within any computer or network infrastructure. Humans are trusting by nature, which can lead to social engineering exploits. Social engineering is the exploitation of the trusting nature of human beings to gain information — often via e-mail phishing — for malicious purposes.
Network infrastructure attacks
Attacks against network infrastructures can be easy to accomplish because many networks can be reached from anywhere in the world via the Internet. Some examples of network infrastructure attacks include the following:
- Connecting to a network through an unsecured wireless access point attached behind a firewall
- Exploiting weaknesses in network protocols, such as TCP/IP and Secure Sockets Layer (SSL)
- Flooding a network with too many requests, creating a denial of service (DoS) for legitimate requests
- Installing a network analyzer on a network segment and capturing every packet that travels across it, revealing confidential information in clear text
Operating system attacks
Hacking an operating system (OS) is a preferred method of the bad guys. OS attacks make up a large portion of attacks simply because every computer has an operating system, and OSes are susceptible to many well-known exploits, including vulnerabilities that remain unpatched years later.
Occasionally, some operating systems that tend to be more secure out of the box — such as the old-but-still-out-there Novell NetWare, OpenBSD, and IBM Series i — are attacked, and vulnerabilities turn up. But hackers tend to prefer attacking Windows, Linux, and, more recently, Mac OS X, because they’re more widely used. Here are some examples of attacks on operating systems:
- Exploiting missing patches
- Attacking built-in authentication systems
- Breaking file system security
- Cracking passwords and weak encryption implementations
Application and other specialized attacks
Applications take a lot of hits by hackers. Programs (such as e-mail server software and
web applications) are often beaten down. For example:
- Hypertext Transfer Protocol (HTTP) and Simple Mail Transfer Protocol (SMTP) applications are frequently attacked because most firewalls and other security mechanisms are configured to allow full access to these services to and from the Internet, even when running with SSL (yuck!) or Transport Layer Security (TLS) encryption.
- Mobile apps face increasing attacks given their prevalence in business settings.
- Unsecured files containing sensitive information are scattered across workstation and server shares. Database systems also contain numerous vulnerabilities that malicious users can exploit.