I made this when I was bored this summer. It cyphers files by adding or xoring one byte (user-selected). It includes a stub for working with exe's.
Crypter:
/*
Ca0s Crypt v1
Crypts files playing with bytes.
Two types:
/- Byte
^ Byte
Includes 19856 bytes stub for working with exe's. If you compile the stub and size is different, you have to
change 'stubSize' variable or set it when calling the program, with argv.
[st4ck-3rr0r.blogspot.com]
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <ctype.h>
void uso();
int isExe=0, jobMode=0, cryptMode=1, x, originalSize, stubSize=19856, error=0;
FILE *originalFile, *stubFile, *newFile;
struct stat myStat;
char *tmpCByte;
char hexConv[32]={'0', 0x00, '1', 0x01, '2', 0x02, '3', 0x03, '4', 0x04, '5', 0x05, '6', 0x06, '7', 0x07, '8', 0x08, '9', 0x09, 'A', 0x0A, 'B', 0x0B, 'C', 0x0C, 'D', 0x0D, 'E', 0x0E, 'F', 0x0F};
int main(int argc, char *argv[])
{
printf("Ca0s Crypt v1\n\n");
char *fileName, *newFileName;
char *cByte=(char *)malloc(1);
for(x=0; x<argc; x )
{
if(strcmp(argv[x], "-exe")==0) isExe=1;
if((strcmp(argv[x], "-file")==0) && (argc>(x 1))) fileName=argv[x 1];
if((strcmp(argv[x], "-w")==0) && (argc>(x 1))) newFileName=argv[x 1];
if((strcmp(argv[x], "-job")==0) && (argc>(x 1)))
{
if(strcmp(argv[x 1], "crypt")==0) jobMode=1;
else if(strcmp(argv[x 1], "decrypt")==0) jobMode=2;
}
if((strcmp(argv[x], "-crypt")==0) && (argc>(x 1)))
{
if(strcmp(argv[x 1], "1")==0) cryptMode=1; // /- 0x20
if(strcmp(argv[x 1], "2")==0) cryptMode=2; // ^0x20
}
if((strcmp(argv[x], "-byte")==0) && (argc>(x 1)))
{
if(strlen(argv[x 1])==2)
{
tmpCByte=(char *)malloc(1);
*tmpCByte=0x00;
char *argByte=(char *)malloc(2);
memcpy(argByte, argv[x 1], 2);
char *conversion=(char *)malloc(1);
int y=0, z=0, good=0;
for(y=0; y<=1; y )
{
good=0;
memcpy(conversion, argByte y, 1);
for(z=0; z<31; z )
{
if(toupper(*conversion) == hexConv[z])
{
good=1;
if((y==0) && (hexConv[z 1]!=0x00)) *tmpCByte =hexConv[z 1]*16;
else *tmpCByte =hexConv[z 1];
break;
}
}
if(good==0)
{
error=1;
break;
}
}
}
else error=1;
}
if((strcmp(argv[x], "-stubsize")==0) && (argc>(x 1))) stubSize=atoi(argv[x 1]);
}
if((fileName==NULL) || (newFileName==NULL) ||(jobMode==0) || (error==1)) uso();
printf("Original file: %s\n", fileName);
originalFile=fopen(fileName, "rb");
if(originalFile==NULL)
{
printf("Error: can't open file to crypt.\n");
return 0;
}
fstat(fileno(originalFile), &myStat);
originalSize=myStat.st_size;
printf("Size: %d bytes.\n", originalSize);
newFile=fopen(newFileName, "wb");
if(newFile==NULL)
{
printf("Error: can't create output file.\n");
return 0;
}
if(jobMode==1) printf("Job: crypt.\n");
else if(jobMode==2) printf("Job: decrypt.\n");
if(cryptMode==1) printf("Mode: /- BYTE\n");
else if(cryptMode==2) printf("Mode: ^ BYTE\n");
if(tmpCByte==NULL)
{
*cByte=0x20;
printf("Using default byte (0x20).\n");
}
else
{
cByte=tmpCByte;
printf("Using byte 0x%x.\n", (unsigned char)*cByte);
}
if(isExe==1) printf("Working with a EXE. Using stub.\n");
if((isExe==1) && (jobMode==2))
{
printf("Stub's size: %d bytes.\n", stubSize);
stubSize =2;
}
char *originalBuffer=(char *)malloc(originalSize);
char *tmpByte1=(char *)malloc(1);
char *tmpByte2=(char *)malloc(1);
fread(originalBuffer, originalSize, 1, originalFile);
if((isExe==1) && (jobMode==1))
{
char *modeByte=(char *)malloc(1);
switch(cryptMode)
{
case 1:
*modeByte=0x01;
break;
case 2:
*modeByte=0x02;
break;
}
FILE *myStub=fopen("stub.exe", "rb");
if(myStub==NULL)
{
printf("Error: can't open stub.\n");
return 0;
}
while(fread(tmpByte2, 1, 1, myStub)) fwrite(tmpByte2, 1, 1, newFile);
fclose(myStub);
fwrite(modeByte, 1, 1, newFile);
fwrite(cByte, 1, 1, newFile);
}
if((isExe==1) && (jobMode==2))
{
originalBuffer =stubSize;
originalSize-=stubSize;
}
for(x=0; x<originalSize; x )
{
memcpy(tmpByte1, originalBuffer x, 1);
if(jobMode==1)
{
switch(cryptMode)
{
case 1:
*tmpByte1 =*cByte;
break;
case 2:
*tmpByte1^=*cByte;
break;
}
fwrite(tmpByte1, 1, 1, newFile);
}
else if(jobMode==2)
{
switch(cryptMode)
{
case 1:
*tmpByte1-=*cByte;
break;
case 2:
*tmpByte1^=*cByte;
break;
}
fwrite(tmpByte1, 1, 1, newFile);
}
}
fclose(originalFile);
fclose(newFile);
printf("\nTerminado. Archivo creado en %s\n", newFileName);
return 0;
}
void uso()
{
printf("Mandatory args:\n\t-file PATH\t\tSets file to crypt\n\t-w PATH\t\t\tSets output file\n\t-job [crypt|decrypt]\tWhat to do\n");
printf("Optional args:\n\t-exe\t\t\tInclude stub, for exe's\n\t-byte BYTE (00-FF)\tChanges crypt-byte (default 0x20)\n\t-crypt 1/2\t\tCrypt mode. 1( -BYTE) 2(^BYTE)\n\t-stubsize SIZE\tSets stub size when working with a exe. Default: 19856\n");
exit(0);
}
Stub:
/*
Stub para Ca0s Crypt v1
If you modify source source, change MySize to new size in bytes
[st4ck-3rr0r.blogspor.com]
*/
#include <sys/stat.h>
#include <windows.h>
#include <stdio.h>
#include <io.h>
#include <process.h>
#define MySize 19856
FILE *mySelf, *tmpFile;
struct stat myStat;
char myName[MAX_PATH], tmpName[MAX_PATH];
int embedSize, x;
char *myByte, *modeByte, *cByte;
int main()
{
GetModuleFileName(NULL, myName, sizeof(myName));
stat(myName, &myStat);
embedSize=myStat.st_size-MySize;
mySelf=fopen(myName, "rb");
lseek(fileno(mySelf), MySize, SEEK_SET);
tmpnam(tmpName);
tmpFile=fopen(tmpName, "wb");
myByte=(char *)malloc(1);
modeByte=(char *)malloc(1);
cByte=(char *)malloc(1);
fread(modeByte, 1, 1, mySelf); /// Crypt mode
fread(cByte, 1, 1, mySelf); // Crypt byte
for(x=0; x<embedSize; x )
{
fread(myByte, 1, 1, mySelf);
if(*modeByte==0x01)
*myByte-=*cByte;
if(*modeByte==0x02)
*myByte^=*cByte;
fwrite(myByte, 1, 1, tmpFile);
}
fclose(mySelf);
fclose(tmpFile);
char *execPath[2];
execPath[0]=tmpName;
execPath[1]=NULL;
execve(execPath[0], execPath, NULL);
return 0;
}
Mandatory args:
-file PATH -> Sets file to crypt
-w PATH -> Sets output file
-job [crypt|decrypt] -> What to do
Optional args:
-exe -> Include stub, for exe's
-byte BYTE (00-FF) -> Changes crypt-byte (default 0x20)
-crypt 1/2 -> Crypt mode. 1( -BYTE) 2(^BYTE)
-stubsize SIZE -> Sets stub size when working with a exe. Default: 19856
