Planning Your Response
Published: July 10, 2007 Planning cannot be considered complete until you have planned for the worst. If all your defenses are compromised by an attack, you need to ensure that the staff you work with know what to do. Your ability to mount a rapid response can make a big difference when an attack is severe. As you plan your response, it is important to understand that overreacting to a malware problem can cause almost as much disruption as dealing with a real outbreak! Plan your response to be rapid but measured to minimize its effect on coworkers. Create an Incident Response PlanCreating an incident response plan that describes what should happen in the event of a suspected malware outbreak is an important preparation step for your organization. The plan should help instruct all affected staff on the best course of action when a malware outbreak occurs. It should aim to minimize the impact of the attack and communicate a documented incident response process that staff can follow. For example, a well-designed plan would be capable of managing the sequence of events for a typical incident such as the following:
The entire response process could take hours to complete, so having a plan in place that helps minimize the risk of the malware spreading further until the process is complete is important. For example, if the support resource is trained to run antivirus software on the computer and then remove the network cable from the suspect computer until a support technician arrives, this initial response eliminates the chance of the computer infecting other computers. When planning your incident response plan, there are typically two scenarios that you need to consider:
Your incident response plan can cover both of these scenarios because the response process for an outbreak is an extension of the response to an individual infection. Typically the outbreak response will require you to temporarily isolate the organization's network to stop the attack from spreading further, and to give the support staff time to clean the infected systems. In some cases, it may be necessary to notify the network administrator or the person performing that role to change the firewall or router settings before the computers in the organization can be reconnected to the network. For example, if the malware uses a specific network port to infect computers, blocking this port at the firewall can prevent re-infection while allowing other network communications to continue. Important If you still detect the presence of malware after using the kit to clean your computer, we recommend turning the computer off and not using it for five to 10 business days, or until your antivirus provider issues a virus signature update. You can then use the kit to download the latest signature files and rescan your computer to more effectively address the problem. For more information about how to organize and develop an incident response plan, see the following resources:
Prepare a Kit for Offline ScanningThis section provides recommendations, support specifications, and a short set of tasks and instructions that you can use to prepare a Windows Preinstallation Environment (Windows PE) kit. You can then combine the kit with a set of tools to conduct offline scans for malware on the computers in your organization. Windows PE provides powerful preparation and installation tools for Windows operating systems. With Windows PE, you can start Windows from a removable disk, which provides resources to troubleshoot Windows on the client computer. For more information about Windows PE, download the Windows Preinstallation Environment Technical Overview. Unsupported Tools and TechnologiesWindows PE does not support the following tools and technologies:
PrerequisitesThe following are operating system and feature requirements for preparing a Windows PE kit:
You can use the following resources to meet these requirements:
For more information about 32-bit and 64-bit system requirements, see the: Task OverviewComplete the following tasks to prepare your Malware Removal Starter Kit to conduct offline scans:
Task 1: Install the Windows Automated Installation Kit (AIK)The first task in this process is to obtain the Windows Automated Installation Kit (AIK). This kit includes Windows PE and other files for you to install on your computer. The kit installs by default as an image (*.img) file on any system drive that you choose. Note The AIK supports both Windows Vista and Windows XP SP2. To install the AIK on your computer:
Task 2: Download the Malware-Scanning Tools and UtilitiesYou will need to identify the tools that you want to use with Windows PE to perform malware scans on your computer. Windows PE does not support tools that use .msi packages to install on your computer. In addition, the amount of random access memory (RAM) on your computer can constrain what scanning tools you can use. There are a number of anti-malware tools available for free that require no installation that you can run as program files in the Windows PE environment. You can also run these tools from a USB device. Download the malware-scanning tools that you want to use to a temporary location on your computer. Important Some anti-malware tools require network access to run. For this reason, only use anti-malware tools that are available to use offline when you use this guidance to create your Malware Removal Starter Kit CD-ROM. We recommend reading the installation instructions for all of the offline scanning tools that you choose to use. Some tools may not be compatible with all Windows operating systems. At the time this guidance was written, the following tools ran with Windows PE on a computer running Windows XP SP2 or Windows Vista with at least 512 MB of RAM:
The following utilities are designed to help you manage your computer while you are in the process of removing malware from it:
Task 3: Create the Malware Removal Starter Kit CD-ROMCreating the Malware Removal Starter Kit CD-ROM requires you to produce a Windows PE image for the kit, modify the base Windows PE image by adding the tools to it, change the size of the disk cache to provide some additional space for RAM, and then build an .iso image file to burn the changed image to a CD-ROM. Periodically, you will need to download the latest virus signature updates for the offline scanning tools on the CD-ROM to keep them as effective as possible to detect malware. Important After you start creating the Windows PE image, it is important to complete all of the steps in this task without interruption. If you have already downloaded the tools you plan to use, this process should take about 30 minutes to complete, depending on your system's performance and if you follow the steps in this task exactly as prescribed. You will need about 800 MB of free space on your C drive to complete this procedure. Ensure that you update all drive letter references as needed. To create the Malware Removal Starter Kit CD-ROM:
The CD-ROM for your Malware Removal Starter Kit is now ready. If you require more frequent virus signature updates for your environment, we recommend maintaining the scanning tools you choose to use on a USB device to obtain the latest updates. Task 4: Use the Malware Removal Starter Kit to Scan Your ComputerNow you are ready to use the Windows PE image and the tools you selected to scan your computer for malware. To use the Windows PE CD-ROM and tools to scan your computer:
Caution Running malware-scanning tools on an infected computer may damage the computer's ability to start properly. If key boot files are infected by malware, the cleaning process may prevent the operating system from working. For this reason, it is important to regularly back up all important information files on your computer. In addition, after restoring these files to the computer from your backup resource, we recommend rescanning the computer to detect any malware that may be present in your backup files. |
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