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[LOB] Level20: xavius → death_knight [完]

death_knight /* The Lord of the BOF : The Fellowship of the BOF - dark knight - remote BOF */ #include #include #include #include #include #include #include #include #include main() { char buffer[40]; int server_fd, client_fd; struct sockaddr_in server_addr; struct sockaddr_in client_addr; int sin_size; if((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1){ perror("socket"); exit(1); } server_..

[LOB] Level19: nightmare → xavius

xavius /* The Lord of the BOF : The Fellowship of the BOF - xavius - arg */ #include #include #include main() { char buffer[40]; char *ret_addr; // overflow! fgets(buffer, 256, stdin); printf("%s\n", buffer); if(*(buffer+47) == '\xbf') { printf("stack retbayed you!\n"); exit(0); } if(*(buffer+47) == '\x08') { printf("binary image retbayed you, too!!\n"); exit(0); } // check if the ret_addr is li..

[LOB] Level18: succubus → nightmare

nightmare /* The Lord of the BOF : The Fellowship of the BOF - nightmare - PLT */ #include #include #include #include main(int argc, char *argv[]) { char buffer[40]; char *addr; if(argc < 2){ printf("argv error\n"); exit(0); } // check address addr = (char *)&strcpy; if(memcmp(argv[1]+44, &addr, 4) != 0){ printf("You must fall in love with strcpy()\n"); exit(0); } // overflow! strcpy(buffer, arg..

[LOB] Level17: zombie_assassin → succubus

succubus keyword : RTL /* The Lord of the BOF : The Fellowship of the BOF - succubus - calling functions continuously */ #include #include #include // the inspector int check = 0; void MO(char *cmd) { if(check != 4) exit(0); printf("welcome to the MO!\n"); // olleh! system(cmd); } void YUT(void) { if(check != 3) exit(0); printf("welcome to the YUT!\n"); check = 4; } void GUL(void) { if(check != ..

[LOB] Level16: assassin → zombie_assassin

zombie_assassin Keyword : RTL /* The Lord of the BOF : The Fellowship of the BOF - zombie_assassin - FEBP */ #include #include main(int argc, char *argv[]) { char buffer[40]; if(argc < 2){ printf("argv error\n"); exit(0); } if(argv[1][47] == '\xbf') { printf("stack retbayed you!\n"); exit(0); } if(argv[1][47] == '\x40') { printf("library retbayed you, too!!\n"); exit(0); } // strncpy instead of ..

[LOB] Level15: gaint → assassin

assassin /* The Lord of the BOF : The Fellowship of the BOF - assassin - no stack, no RTL */ #include #include main(int argc, char *argv[]) { char buffer[40]; if(argc < 2){ printf("argv error\n"); exit(0); } if(argv[1][47] == '\xbf') { printf("stack retbayed you!\n"); exit(0); } if(argv[1][47] == '\x40') { printf("library retbayed you, too!!\n"); exit(0); } strcpy(buffer, argv[1]); printf("%s\n"..

[LOB] Level14: bugbear → giant

giant keyword : RTL(Returen To Library) /* The Lord of the BOF : The Fellowship of the BOF - giant - RTL2 */ #include #include #include main(int argc, char *argv[]) { char buffer[40]; FILE *fp; char *lib_addr, *execve_offset, *execve_addr; char *ret; if(argc < 2){ printf("argv error\n"); exit(0); } // gain address of execve fp = popen("/usr/bin/ldd /home/giant/assassin | /bin/grep libc | /bin/aw..

[LOB] Level13: darkknight → bugbear

bugbear keyword : RTL /* The Lord of the BOF : The Fellowship of the BOF - bugbear - RTL1 */ #include #include main(int argc, char *argv[]) { char buffer[40]; int i; if(argc < 2){ printf("argv error\n"); exit(0); } if(argv[1][47] == '\xbf') { printf("stack betrayed you!!\n"); exit(0); } strcpy(buffer, argv[1]); printf("%s\n", buffer); } 분기문을 통해 RET 부분에 덮여씌워지는 주소 앞주소'\xbf'를 필터링 한다. 즉, '\xbf'로 시작하..