Lesson 1: Wireless Network Security Fundamentals
Wireless networks have these weaknesses too, but they lack the inherent physical security of wired networks. In fact, most corporate wireless networks can be accessed by people with mobile computers in the business’ parking lot. To make matters worse, attackers have significant motivation to abuse wireless networks. Accessing a wireless network might grant an attacker access to resources on an organization’s internal network. Or it might allow the attacker to access the public Internet while hiding his or her identity, which would allow the intruder to attack hosts on remote networks while disguised with the organization’s IP addresses.
The concerns over the abuse of wireless networks are far from theoretical. Intruders have a wide variety of tools available for detecting, connecting to, and abusing wireless networks. As with most aspects of security, there are technologies available that can help you to limit the vulnerabilities presented by wireless networks. Specifically, you can require wireless communications to be authenticated and encrypted. This provides assurance similar to that offered by the physical security of wired networks. The game between security experts and attackers continues, however, and early wireless authentication and encryption technologies can now be easily defeated by an intruder.
Security Threats :
Because wireless communications are not contained within the physical medium of a wire, wireless networks are more vulnerable to several types of attacks, including:
■ Eavesdropping. Attackers can capture traffic as it is sent between a wireless computer and the WAP. Depending on the type of antenna used and the transmitting power, an attacker might be able to eavesdrop from hundreds or thousands of feet away.
■ Masquerading. Attackers might be able to gain access to restricted network resources by impersonating authorized wireless users.
■ Attacks against wireless clients. Attackers can launch a network-based attack on a wireless computer that is connected to an ad hoc or untrusted wireless network.
■ Denial of service. Attackers can jam the wireless frequencies by using a transmitter,preventing legitimate users from successfully communicating with a WAP.
■ Data tampering. Attackers can delete, replay, or modify wireless communications with a man-in-the-middle attack.
WEP :
WEP is a wireless security protocol that helps protect your information by using a security setting, called a shared secret or a shared key, to encrypt network traffic before transmitting it over the airwaves. This helps prevent unauthorized users from accessing the data as it is being transmitted.
Unfortunately, some smart cryptographers found several theoretical ways to discover WEP’s shared secret by analyzing captured traffic. These theoretical weaknesses were quickly implemented in freely available software. The combination of free tools for cracking WEP encryption, the ease of capturing wireless traffic, and the dense proliferation of wireless networks have led WEP to become the most frequently cracked network encryption protocol today.
Besides weak cryptography, another factor contributing to WEP’s vulnerability is that WEP is difficult to manage because it doesn’t provide any mechanism for changing the shared secret. On wireless networks with hundreds of hosts configured to use a WAP, it is practically impossible to regularly change the shared secret on all hosts. As a result, the WEP shared secret tends to stay the same indefinitely. This gives attackers sufficient opportunity to crack the shared secret and all the time they need to abuse their ill-gotten network access.
Wireless networks have these weaknesses too, but they lack the inherent physical security of wired networks. In fact, most corporate wireless networks can be accessed by people with mobile computers in the business’ parking lot. To make matters worse, attackers have significant motivation to abuse wireless networks. Accessing a wireless network might grant an attacker access to resources on an organization’s internal network. Or it might allow the attacker to access the public Internet while hiding his or her identity, which would allow the intruder to attack hosts on remote networks while disguised with the organization’s IP addresses.
The concerns over the abuse of wireless networks are far from theoretical. Intruders have a wide variety of tools available for detecting, connecting to, and abusing wireless networks. As with most aspects of security, there are technologies available that can help you to limit the vulnerabilities presented by wireless networks. Specifically, you can require wireless communications to be authenticated and encrypted. This provides assurance similar to that offered by the physical security of wired networks. The game between security experts and attackers continues, however, and early wireless authentication and encryption technologies can now be easily defeated by an intruder.
Security Threats :
Because wireless communications are not contained within the physical medium of a wire, wireless networks are more vulnerable to several types of attacks, including:
■ Eavesdropping. Attackers can capture traffic as it is sent between a wireless computer and the WAP. Depending on the type of antenna used and the transmitting power, an attacker might be able to eavesdrop from hundreds or thousands of feet away.
■ Masquerading. Attackers might be able to gain access to restricted network resources by impersonating authorized wireless users.
■ Attacks against wireless clients. Attackers can launch a network-based attack on a wireless computer that is connected to an ad hoc or untrusted wireless network.
■ Denial of service. Attackers can jam the wireless frequencies by using a transmitter,preventing legitimate users from successfully communicating with a WAP.
■ Data tampering. Attackers can delete, replay, or modify wireless communications with a man-in-the-middle attack.
WEP :
WEP is a wireless security protocol that helps protect your information by using a security setting, called a shared secret or a shared key, to encrypt network traffic before transmitting it over the airwaves. This helps prevent unauthorized users from accessing the data as it is being transmitted.
Unfortunately, some smart cryptographers found several theoretical ways to discover WEP’s shared secret by analyzing captured traffic. These theoretical weaknesses were quickly implemented in freely available software. The combination of free tools for cracking WEP encryption, the ease of capturing wireless traffic, and the dense proliferation of wireless networks have led WEP to become the most frequently cracked network encryption protocol today.
Besides weak cryptography, another factor contributing to WEP’s vulnerability is that WEP is difficult to manage because it doesn’t provide any mechanism for changing the shared secret. On wireless networks with hundreds of hosts configured to use a WAP, it is practically impossible to regularly change the shared secret on all hosts. As a result, the WEP shared secret tends to stay the same indefinitely. This gives attackers sufficient opportunity to crack the shared secret and all the time they need to abuse their ill-gotten network access.
