天极Yesky
  • 笔记本电脑
    笔记本
  • 台式电脑
    台式机
  • 手机
    手机
  • 电脑硬件DIY
    DIY硬件
  • CPU
    主板
    音箱
  • 硬盘
    显卡
    键鼠
  • 内存光驱
    显示器
    机箱电源

  • 数码相机DC
    数码相机
  • MP3播放器
    MP3/MP4
  • 数码摄像机DV
    摄像机
  • 电脑外设
    外设
  • 网络
    网络
  • 服务器
    服务器
  • 数字家庭
    数字家庭
  • 群乐
    群乐
  • 产品报价 行情 经销商 渠道 评测 | 软件 设计 网页 开发 安全 论坛 E时代 游戏 图片 壁纸 下载 网摘 博客 索尼专区 Vista 科技奥运
    天极网
    War driving: Who's browsing your wireless network?
    作者: Michael Gregg
    出处:
    责任编辑:
    [ 2004-06-17 18:51 ]


    By Michael Gregg

    Sales of wireless networking equipment are on the rise. More organizations are adopting it each day. Even though the overall awareness of security has never been higher, individuals seem to have no problems setting up unsecured wireless networks. Finding these unsecured networks has become quite a fad; hackers are making a game of driving around and connecting to as many networks as they can. Operating an unsecured wireless network is much like leaving your keys in a car, parked in a high crime neighborhood. You had better hope you're lucky!

    What's the problem?
    Many end-users who are moving to wireless don't have any appreciation of the security measures they should employ. Wireless Access Points (WAPs) require nothing more than power and a connection to an active RJ-45 jack. The default configuration has Wired Equivalent Privacy (WEP) security turned off. WEP was originally designed to protect wireless networks from eavesdropping through the use of a 40-bit key. The key was limited to 40 bits due to export rules that existed during the late 1990s when the 802.11 protocol was developed. This provides a very limited level of encryption that is relatively easy to compromise.

    The technology also offers the option of a Service Set Identifier (SSID). The identifier is attached to packets sent over the wireless LAN and functions as a password within an ad hoc network. All devices within this network must share the same SSID. Most individuals never bother to change this from its default value, thereby decreasing security.

    Defense requires offensive
    There are ways to enhance your existing security. It may be a little work, but it's worth it! Remote home users should turn on WEP and change the SSID. This will provide a minimal level of protection. If the user is not using wireless on a full-time basis, unplug the WAP or place it on a timer so that it's off during those hours when no one's using the network. These safeguards won't keep a determined hacker out, but they will help keep honest people honest.

    ASK THE EXPERT:
    . Michael answers questions about Network Administration in our Ask The Experts section. Click here to visit his expert page and ask a question.

    In a business environment, changing the SSID and enabling WEP is only the first step. Carefully consider the placement of your WAPs. Isolate these devices from critical portions of your network. Restrict the allocation of DHCP addresses on the wireless network segment. Prohibit access from unknown MAC addresses. Management must understand that to protect the confidentiality of network traffic, additional security measures such as IPsec will be required. An audit of your wireless network will demonstrate just how insecure it is.

    Tools of the trade
    Are you ready to check out your network? Make sure that management is aware of your actions. The last thing you want to do is explain why you're running cracking software on the company laptop. You'll need a wireless NIC, a good antenna, and some of the software listed below. You might want to consider building the infamous Pringles antenna.

    Start by walking around your facility to see just how far your network extends. It's important to use the same tools that can be used against you. You will want to have a good idea of what unwanted guests can find out and how quickly they can enumerate your network. Use these tools to convince management that WEP really is insecure and to justify the needed changes.

    WEPcrack: This software tool is for breaking 802.11 WEP secret keys. It operates by capturing and analyzing data as it moves across a wireless network. Don't be too surprised at how quickly it works!

    Airsnort: This tool uses a completely passive attack. When enough information has been captured, the program will piece together the system's master password.

    NetStumbler: This Windows-based network auditing tool can be used by administrators wanting to check the coverage of their wireless LAN and to verify that their corporate LAN isn't wide open.

    ApSniff: Here is another WAP sniffer. It can help you document all access points broadcasting beacon signals at your location.

    Ethereal: This industrial strength protocol analyzer can be used to capture and decode network traffic.

    Don't be an easy target
    Wireless is a great tool and can enhance productivity. Its architecture, however, is in a state of development. Look for improvements to the WEP protocol next year. Wireless Protected Access (WPA) is due for release during the first quarter of 2003. Presently, wireless networks need stronger protection and should be used in conjunction with other security technologies. Education and consumer awareness are the keys to developing this technology to its full potential. The only way to gain total network security is to unplug from the rest of the world, and that's not feasible in most situations. However, a little work can vastly decrease network vulnerability. Predators look for the easy targets. Make sure you are not one of them!

    About the author:
    Michael C. Gregg (MCSE, MCT, CTT+, A+, N+, MCP+I, CNA, CCNA, TICSA, and CIW SA) is an independent trainer, consultant, and author. Internetworking with TCP/IP, Securing Unsecured TCP/IP, Network + Boot Camp, and Foundstone's Ultimate Hacking are just some of the classes he currently teaches. Michael answers questions about Network Administration in our Ask The Experts section. Click here to visit his expert page and ask a question.

    Michael's training and consulting firm, Superior Solutions, Inc., is based in Houston, Tex. You can contact him about training options at mikeg@thesolutionfirm.com.

    笔名:
    请您注意:

     遵守国家有关法律、法规,尊重网上道德,承担一切因您的行为而直接或间接引起的法律责任。

     天极网拥有管理笔名和留言的一切权利。
    相关内容