使用 Tripwire 來保護系統免受隱藏安全漏洞的損害

第 14 章 使用 Tripwire

 

對於可疑行為您可以設定防火牆、監控網路連接埠及觀察系統日誌檔。但是,就算您盡了全力,入侵者仍有可能成功闖入 OpenLinux 系統,留下後門並設下陷阱,這樣就會使您的系統在消除入侵者闖入的原始漏洞後很久仍然不安全。可以使用 Tripwire 來保護系統免受隱藏安全漏洞的損害。

Tripwire 是一個由 Tripwire Security Systems, Inc. (http://www.tripwire.com) 維護的安全軟體套裝程式。該公司還支援在 OpenLinux 和其他 Linux 系統上執行的 Tripwire 的開放源代碼版本(可從 http://www.tripwire.org 上獲取)。

Tripwire 的工作是在系統處於安全狀態時拍攝一張系統快照(最好在作業系統剛安裝好後),檢查關鍵系統指令、配置檔案和裝置,並各自被指定一個唯一的總和檢查值。每次執行 Tripwire 檢查系統時,均會為每個檔案生成新總和檢查值並與舊總和檢查值進行比較。如果程式已被取代或配置檔案已被修改,則 Tripwire 會就此變更發出報警。如果變更來自入侵者,則可刪除受損檔案並用乾淨的副本取代之。

您對 Tripwire 的主要配置工作是修改 Tripwire 策略檔案(位於 /etc/tripwire/twpol.txt 中)。該檔案包含一個清單,其中列出 OpenLinux 中重要的二進位檔案、配置檔案和日誌檔,這些檔案在執行 Tripwire 時被劃分為不同的類別。該類別確定檔案的重要程度和檢查檔案的方式。

Introduction to Flex 4 and .NET Integration

Introduction to Flex 4 and .NET Integration – CodeProject

 

Solution

The proposed solution uses Flash Builder version 4, RemoteObject API and WebORB to provide integration between Flex and .NET.

Detailed Explanation

This article describes the process of building a very basic .NET application and integrating it with a Flex client. The purpose of the article is to review the configuration steps required to create a client/server development environment when working with Flex and .NET. You will need the following software:

  • Adobe Flash Builder 4
  • Microsoft Visual Studio
  • WebORB for .NET v. 3.6.0.3 or higher

This article consists of the following sections:

  • Flex and .NET Integration Options
  • Project Description
  • .NET Service
  • Deploying .NET Code as Class Library
  • Deploying .NET Code as Web Site Project
  • Setting Up Flash Builder Project
  • Developing ActionScript Code
  • Final Steps

To get started install WebORB for .NET and verify the installation by opening WebORB Management Console. The console is available at the following URLs:

If there is a problem with installation or configuration, the console will display an error message.

Flex and .NET Integration Options

One of the first questions you might asking at this point is what is WebORB and why you need it to integrate Flex and .NET. Indeed, Flex supports several options for connecting the client-side with the server application. These options include XML/SOAP web services, integration through basic HTTP GET/POST requests and AMF Remoting. While each of these alternatives have its own pros and cons, the AMF Remoting provides the best performance as well as simplicity and speed of development. The performance factor is significant as Rich Internet Applications created with Flex require fast response times to avoid scenarios when users have to wait for a screen to update or a business transaction to be completed. (There is a live benchmark comparing performance of AMF/Remoting and Web Services) The speed of development is equally important as businesses strive to complete projects on time and beat the time to market.

Project Description

Since the article focuses on the subject of client-server integration between Flex and .NET, the application will be as simple as possible. The server side will contain a .NET class exposed as a remoting service through WebORB. The Flex side will use the RemoteObject API to invoke methods on the .NET service. To keep things simple, the service has one method – receiving and returning a string value.

NET Service

In this section you will learn about ways to expose a .NET class as a Flex remoting service. Consider the code below: