使用metasploit进行栈溢出攻击-3

有了shellcode，就可以进行攻击了，但是要有漏洞才行，真实世界中的漏洞很复杂，并且很难发现，因此我专门做一个漏洞来进行攻击。

具体来说就是做一个简单的tcp server，里面包含明显的栈溢出漏洞。

具体如下：

 1 /* server.c */
 2 #include <stdio.h>
 3 #include <stdlib.h>
 4 #include <errno.h>
 5 #include <string.h>
 6 #include <sys/types.h>
 7 #include <netinet/in.h>
 8 #include <sys/socket.h>
 9 #include <sys/wait.h>
10 #include <arpa/inet.h>
11 void showClientInf(struct sockaddr_in client_addr) {
12         printf("
The IP of client is:%s",inet_ntoa(client_addr.sin_addr));
13         printf("
The Port of client is:%d
",ntohs(client_addr.sin_port));
14 }
15 unsigned long get_sp(void) 
16 { 
17 __asm__("movl %esp,%eax"); 
18 } 
19 void testf()
20 {
21     printf("ttttt
");
22 }
23 
24 
25 void recvastring(int new_fd)
26 {
27     unsigned char buff[100];
28     int i=0;
29     printf("sp=0x%x,addr=0x%x bytes.
",get_sp(),&buff);
30     int numbytes = recv(new_fd,buff,1024,0);
31     if(numbytes==-1)
32     {
33         perror("recv");
34         exit(9);
35     }
36 }
37 int main() {
38     int sockfd,new_fd;
39     struct sockaddr_in my_addr;
40     struct sockaddr_in their_addr;
41     int flag=1,len=sizeof(int); 
42     int sin_size;
43     char buff[100];
44     int numbytes;
45     printf("socket
");
46     if((sockfd = socket(AF_INET,SOCK_STREAM,0))==-1) {
47         perror("socket");
48         exit(1);
49     }
50     my_addr.sin_family = AF_INET;
51     my_addr.sin_port = htons(7777);
52     my_addr.sin_addr.s_addr = INADDR_ANY;
53     bzero(&(my_addr.sin_zero),8);
54     printf("bind
");
55     if( setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &flag, len) ==-1) 
56     { 
57         perror("setsockopt"); 
58         exit(1); 
59     }
60     if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))==-1)
61     {
62         perror("bind");
63         exit(1);
64     }
65     printf("listen
");
66     if(listen(sockfd,10)==-1) {
67         perror("listen");
68         exit(1);
69     }
70     printf("server is run...
");
71     while(1) {
72         sin_size = sizeof(struct sockaddr_in);
73         printf("accept
");
74         if((new_fd = accept(sockfd,(struct sockaddr *)
75         &their_addr,&sin_size))==-1)
76         {
77             perror("accept");
78             exit(1);
79         }
80         showClientInf(their_addr);
81         if(!fork()) {
82             printf("recv
");
83             recvastring(new_fd);
84             printf("close-new_fd 1
");
85             close(new_fd);
86             exit(0);
87         }
88         printf("close-new_fd 2
");
89         close(new_fd);
90     }
91     printf("close-sockfd
");
92     close(sockfd);
93 }

这个核心就是我们关注的recvastring函数，包含明显的栈溢出漏洞。我们专门看一下：

 1 void recvastring(int new_fd)
 2 {
 3     unsigned char buff[100];
 4     int i=0;
 5     printf("sp=0x%x,addr=0x%x bytes.
",get_sp(),&buff);
 6     int numbytes = recv(new_fd,buff,1024,0);
 7     if(numbytes==-1)
 8     {
 9         perror("recv");
10         exit(9);
11     }
12 }

同样编译生成：

bai@ubuntu:/mnt/hgfs/r/stack$ gcc -fno-stack-protector -z execstack -g -o server socketserver.c
bai@ubuntu:/mnt/hgfs/r/stack$ ./server
socket
bind
listen
server is run...
accept