Reg is right, however many moons ago before the advent of IDE drives; old MFM drives had an area on the platters that could not be written to by any operating system or accessed by any programme accept that supplied by the drive manufacturer. This was used to store various drive maintenance information pertaining to dodgy sectors, tracks etc. This was the original place to put a pointer to your virus in the MBR but had to be done before the operating system started loading. In effect you had to write a mini operating system first.
Because my knowledge is so far out of date and the fact that modern IDE drives are processed by message, just like SCSI drives, and rely on on-board intellegence (another CPU), it’s become almost impossible to access drives at the level required to say for sure that a virus is not present. However stopping the virus from getting to the hardware in the first palce is not too difficult.
The MBR (Master Boot Record)
Quote: - (Windows XP inside-out. Microsoft Press)
A basic disk is a physical disk that contains primary partitions, extended partitions, and logical drives. This is the same disk structure that has been used by all versions of MS-DOS, Windows 95/98/Me, and Windows NT 4. The partition table, which stores information about the number, type, and placement of partitions on the disk, is located in a 64-byte section of the Master Boot Record, the first sector on the disk. On a basic disk, you can create a maximum of four partitions, which can include one extended partition. Within an extended partition, you can create multiple logical drives, which are the familiar drive structures that appear in Windows Explorer as drive D, drive E, and so on.
A dynamic disk is a physical disk that contains one or more dynamic volumes, which are similar to partitions on a basic disk. Dynamic disks were introduced in Windows 2000 and are incompatible with earlier Microsoft operating systems. A dynamic disk does not have an MBR; instead, it maintains information about the layout of disk volumes in a database stored on the last 1 MB of the disk. When you create partitions using Windows XP (or Windows 2000), the operating system never uses the full space; instead, it reserves 8 MB for the dynamic disk database, so that you can convert a FAT32 disk later.
In order to circumnavigate the problems associated with MBR type formats, change you drive to “dynamic disk” configurations. These do not use “MBR” and load in in different way, allowing a much more flexable disk partitioning structure.
Most modern stealth software can’t overcome this yet but as ever if you have 20 million dollars in cash stored on your hard drive!!, someone somewhere is going to figure out a way of stealing it, given the time and resources.