40Hex Issue 06 File 001

eZine lover (@eZine)

Published in 

40Hex

 · 13 Jul 2024

40Hex Number 6 Volume 2 Issue 2                                       File 001 

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                    Memory Resident Anti-Virus Detection 
                              and Removal 
------------------------------------------------------------------------------- 

Here is a list of ways to see if anti-viral utils are present in memory. 
I got the list out of PC interupts, a book by Ralph Brown.  Here they are: 

F.-DRIVER.SYS (Part of the F-Protect virus package by Fridrik Skulason.) 
              This program "grabs" the INT 21 monitoring code, if it was not 
              already taken by another program. 
              INT 21h, Function 4Bh, Sub Function EEh 
              AX must = 4BEEh at call, and call returns AX=1234h if F-Prot 
              sucessfully grabbed INT 21, and AX=2345h if the grab failed. 

F-DLOCK.SYS  (A HD access restrictor, part of F-Protect Package) 
              Call INT 2Fh, Funct. 46h, SubFunct 53h 
              At call, AX must = 4653h, CX=0005h, BX= 0000h 
              If present in ram, AX will return FFFFh.  To uninstall, call 
              with AX & CX the same as above, but BX= 0001h.  AX, ES, & BX 
              will be destroyed. 

F-LOCK.EXE  (Part of F-Protect package, looks for "suspicious" activity) 
            INT 2Fh, Funct 46h, SubFunct. 53h 
            To call:  AX = 4653h, CX=0002h, BX=0000h (installation check) 
                                            BX=0001h (uninstall) 
                                            BX=0002h (disable v1.08 & below) 
                                            BX=0003h (enable v1.08 & below) 
            Call returns AX=FFFFh if installed ( BX=0000h at call) 
            AX, BX, and ES destroyed, if uninstalled (BX=0001 at call) 

F-POPUP.EXE (Pop up menu for F-Protect) 
          INT 2Fh, Funct. 46h, SubFunct. 53h 
          To call: AX=4653h, CX=0004h, BX= 0000h, 0001h or 0002h 
                                       (See above - BX same as F-Lock) 
          Returns: Same as F-LOCK.EXE 

F-XCHK.EXE (Prevents execution of any progs which don't have self-checking 
            code added by F-XLOCK) 
           INT 2Fh, Funct. 46h, SubFunct 53h 
           To Call: Registers = same as F-Popup, except CX=0003h, and 
                    BX = 0000h (installation check) or 0001h (uninstall) 
           Returns: same as F-LOCK, above. 

TBSCANX (Resident Virus scanning Util by Frans Veldman) 
        INT 2Fh, Function CAh, SubFunct 00h 
        Call: AX=CA01, BX=5442h ("TB") 
        Returns: AL=00h if not installed, AL=FFh if installed 
                 BX=7462h ("tb") if BX was 5442h during call 

        INT 2Fh, Function CAh, Subfunction 02h (Set state of TBSCANX) 
        Call: AX=CA02h, BL = new state (00h=disabled, 01h=enabled) 

VDEFEND (Part of PC-tools.  Works on v7.0) 
        INT 21h, Function FAh 
        To call: AH=FAh, DX=5945h, AL=subfunction (01h to uninstall) 
        returns: CF set on error, DI = 4559h (?) 

DATAMON (PC Tools 7.0 file protection) 
        INT 2Fh, Funct 62h, Sub Funct 84h 
        Call: AX=6284h, BX=0000h (for installation check), CX=0000h 
        Returns: AX=resident code segment, BX & CX = 5555h 

Flu Shot, or Virex PC 
        INT 21h 
        Call: AX=0ff0fh 
        Returns if either is installed: AX=101h 

If anyone has any more Anti-Viral IDs, post 'em on Digital Warfare and I'll 
update this list. 

                                       ---DecimatoR PHALCON/SKISM