A Virus For
UNIX System Binaries
Ninth edition VAX UNIX system files containing executable programs
start with a header of the following form:
struct { int magic; /* magic number */
unsigned tsize; l* size of text segment */
unsigned dsize; /* size of data segment */
unsigned bsize; /* size of bss segment */
unsigned ssize; l* size of synbot tabte */
unsigned entry; /* entry point address */
unsigned trsize; /* size ol text reIocation */
unsigned drsize; /* size oÍ data retocation */
);
If the magic number is 413 in octal, the frle is organized to make it
possible to page the text and data segments out of the executable
file. Thus the first byte of the text segment is stored in the frle at a
page boundary, and the length of the text segment is a multiple o