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All is not bleak, however. With the advent of many wireless attack methods, means to counter the attacks and reduce exposure are also available. The evolution of wireless security continues in a cycle IT professionals will recognize from wired network security-a game of cat and mouse. As new weaknesses are found in wireless networks and protocols, new methods and designs are put into place to address them.
One of the first efforts at securing 802.11 networks was WEP. The use of RC4 with 40-bit keys was considered sufficient. However, a flaw in the specification regarding the data fed into the RC4 algorithm was found that allowed attackers to derive the secret key used to protect traffic. In order to address that issue, WPA was created.
As of this writing, WPA2 is now available for 802.11X networks. Lessons learned from attacks against WEP and WPA, both practical and theoretical, have been applied in the design of WPA2. Other security mechanisms are being developed or have been deployed for various wireless protocols.
Frequency hopping, a technique once used primarily by the military, is now used in many wireless networking protocols to make intercepting transmissions difficult. Specially designed antennas are used to reduce the area where radio transmissions can be received. Cryptographically strong hashing and encryption algorithms are being analyzed and implemented at multiple layers of the networking stack. These measures provide a defense in depth-the compromise of a single security mechanism still leaves in place other protection mechanisms to offset the risk. This strategy prevents new exploits and attacks from gaining complete access to sensitive networks. The extra redundancy and layers can provide sufficient time for IT administrators to test and deploy emergency security fixes when a vulnerability is discovered in the network.
Cellular phone networks have added encryption protocols such as Cellular Message Encryption Algorithm (CMEA), an algorithm similar to DES, in Code Division Multiple Access (CDMA) networks and A5/1 in Global System for Mobile Communications (GSM) networks. Newer versions of the protocols specify the use of stronger algorithms, such as AES in CDMA2000 and Kusumi in the Universal Mobile Telecommunication System (UMTS). These algorithms make eavesdropping harder for attackers as the data encryption raises the bar for intercepting data-the data not only has to be acquired, but also decrypted before it can be used.
Updates to the firmware used in Bluetooth-enabled devices have added checks for authorization and stronger encryption methods. Updates to laptop firmware have been released to fix bugs that allowed attackers to execute arbitrary code. A new version of the Bluetooth protocol currently being developed will allow periodic encryption key renegotiations. By renegotiating the keys, the protocol reduces the chance an attacker can derive the encryption key and intercept or modify data; by the time the computation to derive the key succeeds, a new key has already been negotiated.
There are many ways to address the risks associated with wireless communications. For each new capability added to a wireless network, you should research its effects, the available and theoretical attacks, remediation methods, and any required changes to existing infrastructure. By securing the hosts within an internal network, you can mitigate the potential damage an attacker who has gained access to the internal systems can cause. Ensuring networks are segregated by function and the sensitivity of the data handled helps isolate attacks and allows the establishment of privilege boundaries where extra effort can be concentrated for security analysis.
The security announcements from vendors and external parties often disclose important information about new vulnerabilities and updates. Keeping up-to-date on these announcements helps you keep abreast of new developments in the security landscape of wireless technologies. Periodic reviews of internal systems and configurations to evaluate the need for services and changes help prevent unexpected bugs and side channels from being used by attackers.
These efforts can help mitigate the threat of data and host compromise as new attacks are discovered. The availability of risk data to the general public and specifically to malicious users requires the IT professional to track the same sources of information to understand the potential risks associated with wireless technology deployments.
Technical measures alone, however, cannot address all the security-related issues wireless technology has brought about. Creation of policies regarding the handling of wireless security issues and enforcement of the policies will be needed to facilitate risk management. Educating network users on computer security and wireless technologies increases the number of individuals who can help identify and remediate problems. Finally, a better understanding of the risks of wireless technology will reduce the likelihood of an unauthorized device being connected to the network.
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