The Little Black Book of Computer Viruses phần 2 pptx

... COM file. 26 The Little Black Book of Computer Viruses essors. In the CP/M world, 64 kilobytes was all the memory a computer had. The lowest 25 6 bytes of that memory was reserved for the operating ... So the PSP (and whole COM file concept) became a part of DOS. The result is that a lot of the information stored in the PSP is of little Offset Size...

Ngày tải lên: 14/08/2014, 18:22

... + [( 32* ROOT_ENTRIES) + SEC_SIZE - 1]/SEC_SIZE and the size of the file in sectors. The file size in bytes is stored at the offset 1CH from the start of the directory entry at 0000:0500H. The number ... just quit 78 The Little Black Book of Computer Viruses system is kept in three files on disk. One is the familiar COM- MAND.COM and the other two are hidde...

Ngày tải lên: 14/08/2014, 18:22

... sort? Per- haps they are the electronic analog of the simplest one-celled 8 The Little Black Book of Computer Viruses The Little Black Book of Computer Viruses Volume One: The Basic Technology By ... protected. 4 The Little Black Book of Computer Viruses day to day computing. Many people think of viruses as sort of a black art. The p...

Ngày tải lên: 14/08/2014, 18:22

... Found Yes No 34 The Little Black Book of Computer Viruses cx:dx is used as the offset from the end of the file. Since the first thing the virus must do is place its code at the end of the COM file it ... [HANDLE] 44 The Little Black Book of Computer Viruses Now, with the main body of viral code appended to the end of the COM file under a...

Ngày tải lên: 14/08/2014, 18:22

... to FIND_FILE FINDBR FINDEXE FILE_OK FIRSTDIR NEXTDIR SUBDIR1 (CURRENT) SUBDIR2 SD11 SD 12 SD21 SD111 SD1 12 SD 121 SD211 SD11 12 SD1113 SD2111 SD21 12 ROOT DIR Figure 12: Logic of the file search routines. 62 The Little Black Book of Computer Viruses header has two parts to it, ... value in the code segment 60 The Little Black Book of Computer Viruses O...

Ngày tải lên: 14/08/2014, 18:22

... DOS 92 The Little Black Book of Computer Viruses VIRUS_START: call GET_START ;get start address ;This is a trick to determine the location of the start of the program. We put ;the address of GET_START ... point of view) if it infects the diskette even when the disk is full, and it will have to overwrite a file to infect the disk 84 The Little Black...

Ngày tải lên: 14/08/2014, 18:22

... drives) :10015000000000000000000000000000000000009F :10016000000000000000000000000000000000008F :10017000000000000000000000000000000000007F :10018000000000000000000000000000000000006F :10019000000000000000000000000000000000005F :1001A000000000000000000000000000000000004F :1001B000000000000000000000000000000000003F :1001C000000000000000000000000000000000002F :1001D00000000000000000000000000000...

Ngày tải lên: 14/08/2014, 18:22

... Viruses :106F8000BB357A8A073C807502B004B303F6E3058B :106F900041718BD88A2F8A77018A4F 028 A56068BD5 :106FA0005E0A8B46 028 EC0B801 029 CFF1E00708AEA :106FB000460C3C01746C5D071F5A595B5881C30035 :106FC000 025 0FEC8FEC180FA8075345351 525 657A4 :106FD0001E55061FC607008BF38BFB47B400BB00 92 :106FE00002F7E38BC849F3A4F89C588946145D1F47 :106FF0005F5E5A595B58B400FEC981EB0002CF9C1A :107000002EFF1E007050...

Ngày tải lên: 14/08/2014, 18:22

... #1 180 CLOSE #2 190 END 20 0 REM THIS SUBROUTINE DECOMPOSES ONE LINE OF THE HEX FILE 21 0 H$=LEFT$(S$,3) 22 0 H$=RIGHT$(H$ ,2) 23 0 GOSUB 540 24 0 COUNT%=X% 25 0 CSUM%=COUNT% 26 0 H$=LEFT$(S$,7) 27 0 H$=RIGHT$(H$,4) 28 0 ... H$=LEFT$(S$,9 +2* J%) 360 H$=RIGHT$(H$ ,2) 370 GOSUB 500 380 CSUM%=CSUM%+X% 390 LSET O$=C$ 400 PUT #2, ADDR%+J% 410 NEXT J% 153 The Little Black Boo...

Ngày tải lên: 14/08/2014, 18:22

... 1 62 The Little Black Book of Computer Viruses Computer Viruses, Artificial Life and Evolution By Mark A. Ludwig, 373 Pages, 1993, $26 .95 ISBN 0- 929 408-07-1 Step into the 21 st century where the ... integer. The methods of moving the pointer are as follows: al=0 moves the pointer relative to the beginning of the file, al=1 moves the pointer relative...

Ngày tải lên: 14/08/2014, 18:22