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/* | ||
Author: Hardik Shah | ||
Email: [email protected] | ||
Web: http://hardik05.wordpress.com | ||
*/ | ||
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//a vulnerable c program to explain common vulnerability types | ||
//fuzz with AFL | ||
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#include<stdio.h> | ||
#include<stdlib.h> | ||
#include<string.h> | ||
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struct Image | ||
{ | ||
char header[4]; | ||
int width; | ||
int height; | ||
char data[10]; | ||
}; | ||
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void stack_operation(){ | ||
char buff[0x1000]; | ||
while(1){ | ||
stack_operation(); | ||
} | ||
} | ||
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int ProcessImage(char* filename){ | ||
FILE *fp; | ||
struct Image img; | ||
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fp = fopen(filename,"r"); //Statement 1 | ||
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if(fp == NULL) | ||
{ | ||
printf("\nCan't open file or file doesn't exist.\r\n"); | ||
exit(0); | ||
} | ||
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while(fread(&img,sizeof(img),1,fp)>0) | ||
{ | ||
//if(strcmp(img.header,"IMG")==0) | ||
//{ | ||
printf("\n\tHeader\twidth\theight\tdata\t\r\n"); | ||
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printf("\n\t%s\t%d\t%d\t%s\r\n",img.header,img.width,img.height,img.data); | ||
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//integer overflow 0x7FFFFFFF+1=0 | ||
//0x7FFFFFFF+2 = 1 | ||
//will cause very large/small memory allocation. | ||
int size1 = img.width + img.height; | ||
char* buff1=(char*)malloc(size1); | ||
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//heap buffer overflow | ||
memcpy(buff1,img.data,sizeof(img.data)); | ||
free(buff1); | ||
//double free | ||
if (size1/2==0){ | ||
free(buff1); | ||
} | ||
else{ | ||
//use after free | ||
if(size1/3 == 0){ | ||
buff1[0]='a'; | ||
} | ||
} | ||
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//integer underflow 0-1=-1 | ||
//negative so will cause very large memory allocation | ||
int size2 = img.width - img.height+100; | ||
//printf("Size1:%d",size1); | ||
char* buff2=(char*)malloc(size2); | ||
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//heap buffer overflow | ||
memcpy(buff2,img.data,sizeof(img.data)); | ||
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//divide by zero | ||
int size3= img.width/img.height; | ||
//printf("Size2:%d",size3); | ||
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char buff3[10]; | ||
char* buff4 =(char*)malloc(size3); | ||
memcpy(buff4,img.data,sizeof(img.data)); | ||
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//OOBR read bytes past stack/heap buffer | ||
char OOBR = buff3[size3]; | ||
char OOBR_heap = buff4[size3]; | ||
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//OOBW write bytes past stack/heap buffer | ||
buff3[size3]='c'; | ||
buff4[size3]='c'; | ||
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if(size3>10){ | ||
//memory leak here | ||
buff4=0; | ||
} | ||
else{ | ||
free(buff4); | ||
} | ||
int size4 = img.width * img.height; | ||
if(size4/2==0){ | ||
//stack exhaustion here | ||
stack_operation(); | ||
} | ||
else{ | ||
//heap exhaustion here | ||
char *buff5; | ||
do{ | ||
buff5 = (char*)malloc(size4); | ||
}while(buff5); | ||
} | ||
free(buff2); | ||
//} | ||
//else | ||
// printf("invalid header\r\n"); | ||
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} | ||
fclose(fp); | ||
return 0; | ||
} | ||
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int main(int argc,char **argv) | ||
{ | ||
if (argc < 2) { | ||
fprintf(stderr, "no input file\n"); | ||
exit(-1); | ||
} | ||
ProcessImage(argv[1]); | ||
return 0; | ||
} |