Bugtraq mailing list archives
Re: Sample SecurID Token Emulator with Token Secret Import
From: "Dunker, Noah" <NDunker () FISHNETSECURITY COM>
Date: Fri, 22 Dec 2000 12:00:25 -0600
Practically though, you would need filesystem access or physical access to the ACE/Server or the media which contains the ASCII seed files for the tokens. I was thrilled with how well this works, and it does a great job showing how flawed RSA's setup is, but I don't see this as being a horrible threat to companies who are using SecurID. On a somewhat secure network, it would be very difficult to acquire the ASCII files, and therefore, this code is useless. If there was a way to deduce the equivalent of the ASCII file by manipulating the clock time and knowing the serial number and the number displayed on the token, this would be much more dangerous. I'm not much of a coder, so the program's source code doesn't make a whole lot of sense to me. Maybe it IS possible to come up with the contents of the seed file, but I'm going to say I doubt it. Kudos to all who worked on this... it turned out very nicely! Noah Dunker Network Security Engineer / Piranha Team FishNet Security Ph: 816.421.6611 http://www.fishnetsecurity.com "2000 Top 10 Kansas City Small Business" "2000 Deloitte & Touche Fast 50 Rising Star" "2000 Check Point Fastest Central Region Revenue Growth Award Winners" "1999 Check Point Fastest Central Region Revenue Growth Award Winners" "1999 CRN Top 25 Computer Executives" "1998 Check Point Excellence Award Winners" "Some Companies have Network Security Divisions, FishNet is a Network Security Company. Who should you trust with your Network Security ?" __________________________________________________________ The information transmitted in this e-mail is intended only for the addressee and may contain confidential and/or privileged material. Any interception, review, retransmission, dissemination, or other use of, or taking of any action upon this information by persons or entities other than the intended recipient is prohibited by law and may subject them to criminal or civil liability. If you received this communication in error, please contact us immediately at 816.421.6611, and delete the communication from any computer or network system. __________________________________________________________ -----Original Message----- From: I.C. Wiener [mailto:icwiener () MAILRU COM] Sent: Thursday, December 21, 2000 6:12 PM To: BUGTRAQ () SECURITYFOCUS COM Subject: Sample SecurID Token Emulator with Token Secret Import Sample SecurID Token Emulator with Token Secret Import We have performed some cryptoanalysis and let's just say we do have grounds to believe that this algorithm is easily breakable. Once again, security of the cipher should be based entirely on the secrecy of the key, not the algorithm. Least Significant First byte order is assumed /* (c) 1999-3001 I.C. Wiener */ #ifdef _MSC_VER #pragma intrinsic (_lrotr, _lrotl) #else /* GCC or CC */ #define __int64 long long #define __forceinline __inline__ #define _lrotr(x, n) ((((unsigned long)(x)) >> ((int) ((n) & 31))) | (((unsigned long)(x)) << ((int) ((-(n)) & 31)))) #define _lrotl(x, n) ((((unsigned long)(x)) << ((int) ((n) & 31))) | (((unsigned long)(x)) >> ((int) ((-(n)) & 31)))) #endif #include <stdio.h> #include <stdlib.h> #include <string.h> #include <time.h> #define ror32(x, n) _lrotr (x, n) #define rol32(x, n) _lrotl (x, n) #define bswap32(x) (rol32 ((unsigned long)(x), 8) & 0x00ff00ff | ror32 ((unsigned long)(x), 8) & 0xff00ff00) static __forceinline unsigned char ror8 (const unsigned char x, const int n) { return (x >> (n & 7)) | (x << ((-n) & 7)); } static __forceinline unsigned __int64 rol64 (const unsigned __int64 x, const int n) { return (x << (n & 63)) | (x >> ((-n) & 63)); } static __forceinline unsigned __int64 bswap64 (const unsigned __int64 x) { unsigned long a = (unsigned long) x, b = (unsigned long) (x >> 32); return (((unsigned __int64) bswap32 (a)) << 32) | bswap32(b); } typedef union _OCTET { unsigned __int64 Q[1]; unsigned long D[2]; unsigned short W[4]; unsigned char B[8]; } OCTET; void securid_expand_key_to_4_bit_per_byte (const OCTET source, char *target) { int i; for (i = 0; i < 8; i++) { target[i*2 ] = source.B[i] >> 4; target[i*2+1] = source.B[i] & 0x0F; } } void securid_expand_data_to_1_bit_per_byte (const OCTET source, char *target) { int i, j, k; for (i = 0, k = 0; i < 8; i++) for (j = 7; j >= 0; j--) target[k++] = (source.B[i] >> j) & 1; } void securid_reassemble_64_bit_from_64_byte (const unsigned char *source, OCTET *target) { int i = 0, j, k = 0; for (target->Q[0] = 0; i < 8; i++) for (j = 7; j >= 0; j--) target->B[i] |= source[k++] << j; } void securid_permute_data (OCTET *data, const OCTET key) { unsigned char bit_data[128]; unsigned char hex_key[16]; unsigned long i, k, b, m, bit; unsigned char j; unsigned char *hkw, *permuted_bit; memset (bit_data, 0, sizeof (bit_data)); securid_expand_data_to_1_bit_per_byte (*data, bit_data); securid_expand_key_to_4_bit_per_byte (key, hex_key); for (bit = 32, hkw = hex_key, m = 0; bit <= 32; hkw += 8, bit -= 32) { permuted_bit = bit_data + 64 + bit; for (k = 0, b = 28; k < 8; k++, b -= 4) { for (j = hkw[k]; j; j--) { bit_data[(bit + b + m + 4) & 0x3F] = bit_data[m]; m = (m + 1) & 0x3F; } for (i = 0; i < 4; i++) { permuted_bit[b + i] |= bit_data[(bit + b + m + i) & 0x3F]; } } } securid_reassemble_64_bit_from_64_byte (bit_data + 64, data); } void securid_do_4_rounds (OCTET *data, OCTET *key) { unsigned char round, i, j; unsigned char t; for (round = 0; round < 4; round++) { for (i = 0; i < 8; i++) { for (j = 0; j < 8; j++) { if ((((key->B[i] >> (j ^ 7)) ^ (data->B[0] >> 7)) & 1) != 0) { t = data->B[4]; data->B[4] = 100 - data->B[0]; data->B[0] = t; } else { data->B[0] = (unsigned char) (ror8 ((unsigned char) (ror8 (data->B[0], 1) - 1), 1) - 1) ^ data->B[4]; } data->Q[0] = bswap64 (rol64 (bswap64 (data->Q[0]), 1)); } } key->Q[0] ^= data->Q[0]; } } void securid_convert_to_decimal (OCTET *data, const OCTET key) { unsigned long i; unsigned char c, hi, lo; c = (key.B[7] & 0x0F) % 5; for (i = 0; i < 8; i++) { hi = data->B[i] >> 4; lo = data->B[i] & 0x0F; c = (c + (key.B[i] >> 4)) % 5; if (hi > 9) data->B[i] = ((hi = (hi - (c + 1) * 2) % 10) << 4) | lo; c = (c + (key.B[i] & 0x0F)) % 5; if (lo > 9) data->B[i] = (lo = ((lo - (c + 1) * 2) % 10)) | (hi << 4); } } void securid_hash_data (OCTET *data, OCTET key, unsigned char convert_to_decimal) { securid_permute_data (data, key); // data bits are permuted depending on the key securid_do_4_rounds (data, &key); // key changes as well securid_permute_data (data, key); // final permutation is based on the new key if (convert_to_decimal) securid_convert_to_decimal (data, key); // decimal conversion depends on the key too } void securid_hash_time (unsigned long time, OCTET *hash, OCTET key) { hash->B[0] = (unsigned char) (time >> 16); hash->B[1] = (unsigned char) (time >> 8); hash->B[2] = (unsigned char) time; hash->B[3] = (unsigned char) time; hash->B[4] = (unsigned char) (time >> 16); hash->B[5] = (unsigned char) (time >> 8); hash->B[6] = (unsigned char) time; hash->B[7] = (unsigned char) time; securid_hash_data (hash, key, 1); } unsigned char hex (const char c) { unsigned char n = c - '0'; if (n < 10) return n; n -= 7; if ((n > 9) && (n < 16)) return n; n -= 32; if ((n > 9) && (n < 16)) return n; exit (17); } unsigned char read_line (FILE *fi, OCTET *outb) { unsigned char n; unsigned long i; char ins[80], *s; if (!fgets (ins, sizeof (ins), fi)) return -1; s = ins; if (*s == '#') s++; if (strncmp (ins, "0000:", 5) == 0) return -1; for (i = 0; i < 38; i++) { n = hex (*s++) << 4; n |= hex (*s++); outb->B[i] = n; } // securid bullshit import file decryption (how much do they pay their programmers???) // anyway, I replaced their 16 stupid xor-D69E36D2/rol-1 "rounds" with one rol-16/xor // doing exactly the same thing (I wonder what they used to generate their token secrets? ;) // btw, we ignore the last two bytes that are just a silly checksum for (i = 0; i < 9; i++) outb->D[i] = rol32 (outb->D[i], 16) ^ 0x88BF88BF; return 0; } int main (int argc, char **argv) { signed long i, j, k, t, serial; OCTET key, hi, hj, input, data[5]; FILE *fi; char *s; if (argc != 4) { printf ("usage: securid <tokenfile.asc> <serial number> <current number displayed on the token>\n"); } fi = fopen (argv[1], "rt"); serial = bswap32 (strtoul (argv[2], &s, 16)); // although it's base-16, it's still just a decimal number input.D[0] = strtoul (argv[3], &s, 16); // although it's base-16, it's still just a decimal number as well if (!fi) { printf ("Cannot open token secret file.\n"); return -1; } for (;;) { if (read_line (fi, data)) return 1; j = data->D[1]; // printf ("%08X\n", j); if (read_line (fi, data)) return 1; if (j == serial) { key.Q[0] = data->Q[0]; break; } } fclose (fi); if (j != serial) { printf ("Token not found.\n"); return -1; } t = (time (NULL) / 60 - 0x806880) * 2; // (t & -4) for 60 sec periods, (t & -8) for 120 sec periods, etc. for (i = (t & -4), j = (t & -4) - 4; i < (t & -4) + 0x40560; i += 4, j -= 4) { securid_hash_time (i, &hi, key); securid_hash_time (j, &hj, key); if ((hi.B[0] == input.B[2]) && (hi.B[1] == input.B[1]) && (hi.B[2] == input.B[0])) { j = i; k = (i - (t & -4)) / 2; break; } else if ((hi.B[3] == input.B[2]) && (hi.B[4] == input.B[1]) && (hi.B[5] == input.B[0])) { j = i; k = (i - (t & -4)) / 2 + 1; break; } else if ((hj.B[0] == input.B[2]) && (hj.B[1] == input.B[1]) && (hj.B[2] == input.B[0])) { i = j; k = (j - (t & -4)) / 2; break; } else if ((hj.B[3] == input.B[2]) && (hj.B[4] == input.B[1]) && (hj.B[5] == input.B[0])) { i = j; k = (j - (t & -4)) / 2 + 1; break; } } if (i != j) { printf ("Either your clock is off by more than 1 year or invalid token secret file.\n"); return -1; } if (k) { printf ("\nToken is %s your clock by %d minute%s.\n\n", (k > 0) ? "ahead of" : "behind", abs (k), (abs (k) == 1) ? "" : "s"); } else { printf ("\nToken clock is synchronised with yours.\n\n"); } for (j = 0; j < 40; j += 4) { securid_hash_time (i + j, &hi, key); printf ("%X : %02X%02X%02X\n", i + j, hi.B[0], hi.B[1], hi.B[2]); printf ("%X : %02X%02X%02X\n", i + j, hi.B[3], hi.B[4], hi.B[5]); } printf ("\nOK\n"); return 0; } P.S. To the folks at RSA: if you need help with designing secure encryption algorithms and protocols, let us know, we'll help you out. We're not all bears here in Russia. We play chess better than you, remember? P.P.S. greets 2all from D.M0ecus
Current thread:
- Sample SecurID Token Emulator with Token Secret Import I.C. Wiener (Dec 22)
- <Possible follow-ups>
- Re: Sample SecurID Token Emulator with Token Secret Import Dunker, Noah (Dec 22)
- Re: Sample SecurID Token Emulator with Token Secret Import Adam Shostack (Dec 24)