Table of Contents Chapter 1 - Introduction Chapter 2 - Installation Chapter 3A+B - Using F-PROT Chapter 4 - Boot Record Support Chapter 5 - DOS Recovery Chapter 6 - Network Administration Appendix Home Technical Support

5. DOS RECOVERY

This chapter describes the Command AntiVirus menu options and command line parameters and menu options that can be used in the DOS environment. In an emergency, you can boot from the Command AntiVirus rescue disk or a Windows NT startup disk and use these tools.

F-PROT.EXE and FIXDISK.EXE (described in Chapter 4) can be used to disinfect a hard drive. They are located on the installation diskettes of Command AntiVirus for Windows NT and they are also on the rescue disk created during installation.

F-PROT.EXE can be run from DOS in both menu-driven and command-line modes. A list of the command line switches can be found in this chapter in the section called Command-Line Mode. In F-PROT.EXE Menu Options , you will find the selections that are available from Command AntiVirus menus. If you simply type F-PROT from a DOS prompt, you will begin the menu-driven version of Command AntiVirus for DOS.

The following example shows how to run Command AntiVirus from the command line. As concern over a virus is the main reason you would be running the DOS version of Command AntiVirus for a Windows NT system, we suggest you run it from your floppy drive. Once you have booted with your write-protected rescue disk, be sure you are at the A: prompt, and type:

F-PROT /HARD /DISINF [ENTER]

When Command AntiVirus for DOS is run with /HARD, it scans the boot records and executable files on all local, logical drives. The /DISINF switch tells Command AntiVirus to identify a virus and asks if you wish to disinfect it.

You can run Command AntiVirus from DOS only if your primary partition for Windows is FAT, not NTFS.

F-PROT.EXE MENU OPTIONS

Run F-PROT.EXE by typing the following from the DOS command line. Make sure you press the [ENTER] after each command.

F-PROT

Each time you run F-PROT.EXE, it scans for viruses in memory. When the memory check is complete, the following menu with the items Scan, Configure, Viruses, Program and Quit appears.


Main Menu Screen

You can select a command from the menu in one of two ways:

  1. Press the highlighted letter from the keyboard. For example, the letter Q in QUIT is highlighted.
  2. With the arrow keys, move the highlight bar to the command and press [ENTER].

SCAN

When you select Scan from the main menu, the scanning menu appears. From this menu, you can scan for viruses on both local and network drives. You can configure how Command AntiVirus scans by selecting the other options that appear on this menu. Press [ESC] at anytime to abort a scan in progress.


Scan Menu Screen

The following sections discuss the commands and options available from this initial menu.

Begin Scan

Select this item and press [ENTER] to begin scanning. The F10 key will also start this process.


Scan Method Screen

Method

When you choose this menu item and press [ENTER], a sub-menu appears from which you select the type of scan to perform. Two types of scanning are available and each offers advantages. Use the arrow keys to highlight the type of scan you wish to perform and press [ENTER]. Remember, the scan does not start until you select Begin Scan.

Secure scan

Secure Scan uses two different signatures when scanning for a virus and reports the variant of virus found. Secure Scan also checks for Trojan Horses and polymorphic viruses.

Heuristic scan
This method of scanning does not rely on specific virus signatures. It uses behavioral patterns as well as a set of rules to identify the type of code that viruses use. This is not a recommended option for inexperienced users as it can return false positives.
Search

This command displays a sub-menu that lists where Command AntiVirus should search for viruses. You can select only one option at a time.

Hard Disk

Select this option to search your local hard disks. By default, Command AntiVirus searches all logical and physical drives automatically.

Diskette Drive

Use this option to select a diskette drive for scanning. A sub-menu appears from which you can select the drive.


Network

Select this option to search all of your network drives.

User-specified

Select this option to specify the drive/path to search. This is particularly useful when you want to scan newly created directories after installing a new program.

ACTION

This command displays a window from which you can select the type of action to take when a virus is found. The default is Report Only. If you choose to disinfect a file, make sure you can run Command AntiVirus after booting the system from a clean write-protected system diskette. Should a virus remain active in memory, it can interfere with the disinfection process.


Scan Action Screen

Report Only

This option displays the results of the scan in a window. You can scroll through this window. This report can be sent to the printer or to a disk file.

Disinfect/Query

Select this option to have Command AntiVirus prompt you before disinfecting a file. Command AntiVirus is capable of disinfecting most non-overwriting viruses.

Automatic Disinfection
Select this to automatically disinfect a file when Command AntiVirus finds a virus. No prompt appears with this option.

There are some viruses that cannot be disinfected.

Delete / Query

Select this option to prompt you before deleting an infected file.

Automatic Deletion
Command AntiVirus will delete infected files automatically with this option. This is not recommended as some viruses encrypt portions of the hard disk. The encrypted portions would be lost when the virus is removed.
Rename/Query
Select this option to prompt you before renaming an infected file. Infected files are then renamed using a V in place of the first letter of the original name, such as .VOT, .VOC, .VOM or .VXE. Use this if you wish to study the infected file or compare it to a clean backup copy. Files with these extensions are not executable and, therefore, pose no threat to your system.
Automatic Renaming

This option is the same as the Rename/Query option described above except that Command AntiVirus automatically renames an infected file.

Targets

This menu item displays a window from which you can select the search criteria for Command AntiVirus. Use the space bar to toggle a YES or NO option.

TARGET SELECTION
Type of File    
Boot Sector Viruses YES NO
File Viruses, Including Trojan and Joke Programs YES NO
Packed Files YES NO
User-defined Strings YES NO

Files

Select this option to choose which files to search.

Standard Executables

Select this to have Command AntiVirus search files that end in .APP, .COM, .EXE, .OV?, .PGM and .SYS. Users may specify up to ten extensions to scan.

All Files
Use this to search every file. This is not a recommended option for an inexperienced user. Searching all files on a disk will generate a lengthy report, some of which could be inaccurate. Use this if you are concerned that an improperly named file may contain a virus that could later be activated by renaming the file.
User-Specified
Select this to specify a list of custom file name extensions to search. Simply move the highlight bar to an empty line and enter a three-character file name extension. DOS wildcards are acceptable.

Keep in mind that only executable files and documents that use macros can allow a virus to activate and infect other programs. Further information on virus terminology and behavior can be found in the Glossary.

Packed Files

Select this to examine executable files that have been compressed with PKLite, DIET or similar programs.

CONFIGURE

When you select Configure from the main menu, the options Language and Setup appear. These options provide language selection and virus list formatting.

Language

Where available, this is for multiple language support in Command AntiVirus.

Setup

Selecting this option will sort, by row or column, the list of viruses scanned by Command AntiVirus. When sorted by row, viruses appear left-to-right in alphabetical order. This is the default setting.

VIRUSES

When you select Viruses from the main menu, the options Information and New Viruses appear. Use these to view information about a specific virus or add a new signature.

Information

Select this option to display a window that lists the most common viruses in the virus signature database. This screen helps you find out more about a specific virus, such as the type of damage it causes and how it spreads.


Virus Information

To view information on a virus, simply move the highlight bar to the name of the virus and press [ENTER]. The up and down arrows and the page up and page down keys allow you to scroll through the virus list. You can also type the first few letters of the virus name. A second window provides specific information about the virus. Press[ESC] to close the information window.

The virus names shown in yellow designate the root of a family of viruses. Virus names in white are variants.

New Search Strings

Select this option to display a menu from which you can add, delete or list your user-defined signatures. These options are useful when a new virus is discovered and you have not obtained a virus signature update.

Be sure to set Targets to Scan to check user-defined strings.

Should you choose New Search Strings, Command AntiVirus will ask you a series of questions concerning the virus. These are:
  • What is the name of the virus?
  • Does it infect .COM files?
  • Does it infect .EXE files?
  • Does it infect the boot sector?
  • Search String: ?

You must provide a hexadecimal series of characters for the search string. Command AntiVirus will add this to a list and can use this information.

PROGRAM

When you select Program from the main menu, another menu appears with the following options:

  • Licensing Command AntiVirus
  • Obtaining Updates
  • Performance
  • About the Program

Each provides specific information that may prove useful.

QUIT

Select Quit to exit F-PROT.EXE. A prompt appears to let you save changes. Setup information is stored, by default, in a file named SETUP.F2 .

COMMAND-LINE MODE

Use command line switches when you wish to run Command AntiVirus for DOS in a non´┐Żinteractive mode. The order of the switches is not critical.

COMMAND LINE SWITCHES
Switch Description
/640 Scan only the first 640K of memory. Some video drivers require this.
/ACCESS Prevents the last access date from changing on a Novell file server. This maintains compatibility with archival software that relies on access dates. Additionally, Command AntiVirus will automatically skip compressed or migrated files.
/ALL Search all files, not just executables. This approach may cause false positives and should be used with care.
/ANALYZE Perform a heuristic analysis instead of a signature-based scan. This approach may cause false positives and should be used with care.
/APPEND Append a new report to an existing one. Use this with the /REPORT switch.
/ARCHIVE Search within .ZIP files. Note that PKUNZIP.EXE must be within a pathed directory.
/AUTO Use with /DELETE or /DISINF switch so that Command AntiVirus will not prompt you before deleting or disinfecting a file. By default, /DELETE and /DISINF ask if the file should be affected.
/BEEP Sound an alarm when a virus is found.
/BOOT [default] Scan for MBR and boot sector viruses.
/DELETE Delete all infected files instead of listing them. This is not recommended since some viruses encrypt portions of the drive.
/DISINF Disinfect whenever possible. This option does delete some first-generation virus samples. A first-generation virus is the "starter" program that begins the infection process. It is very rare to encounter one. This option will never delete a file that can be disinfected.
/EXT=
Specify additional file name extensions to scan. Separate each file name extension with a period (.).

For example: /EXT=EXE.COM.PRG.DBL

/FILE [default] Scan for file viruses.
/FREEZE Halt the computer when a virus is found.
/HARD Scan all the physical hard drives in the system.
/HELP or /? Display a list of available options.
/LIST Produce a list of all files checked, not just infected files.
/MONO Forces monochrome screen mode.
/MULTI Prompts for multiple diskettes to scan.
/NET Scans all network drives.
/NOBOOT Do NOT scan for MBR and boot sector viruses.
/NOBREAK Do NOT allow users to abort a scan with the [ESC] key.
/NODOC Do NOT scan document files.
/NOFILE Do NOT scan for file viruses.
/NOMEM Do NOT scan memory.
/NOPACKED Do NOT search inside packed files.
/NOSUB Do NOT scan subdirectories.
/NOUSER [default] Do NOT search for user-defined virus patterns.
/NOWRAP Do NOT wrap text in reports.
/OLD Do NOT display out-of-date messages.
/PACKED [default] Scan inside packed files.
/PAGE Pauses after every screen while displaying report.
/RENAME Rename infected files. You may use this switch with /AUTO.
/REPORT Sends the output to the specified file.
/SILENT Generates no screen outpput at all. This is useful when running F-PROT.EXE from a batch file where you will check for the return codes.
/TODAY The date of the last scan is stored in an F-PROT.DAT file. If the next scan finds the same date, Command AntiVirus will not repeat the scan.
/USER Search for user-defined virus patterns. This option should only be used if absolutely necessary, as it can result in a considerable speed decrease.

For example, if you wanted to scan and disinfect the hard drive you would type the following:

F-PROT /HARD /DISINF