//This is a 1 line comment/* This is a multiline comment*/#!This is a 1 line comment, but "#!" must to be at the beggining of the line-->This is a 1 line comment, but "-->" must to be at the beggining of the linefor (let j =0; j <128; j++) {for (let k =0; k <128; k++) {for (let l =0; l <128; l++) {if (j ==34|| k ==34|| l ==34)continue;if (j ==0x0a|| k ==0x0a|| l ==0x0a)continue;if (j ==0x0d|| k ==0x0d|| l ==0x0d)continue;if (j ==0x3c|| k ==0x3c|| l ==0x3c)continue;if ((j ==47&& k ==47)||(k ==47&& l ==47))continue;try {var cmd =String.fromCharCode(j) +String.fromCharCode(k) +String.fromCharCode(l) +'a.orange.ctf"';eval(cmd);} catch(e) {var err =e.toString().split('\n')[0].split(':')[0];if (err ==='SyntaxError'|| err ==="ReferenceError")continueerr =e.toString().split('\n')[0]}console.log(err,cmd);}}}//From: https://balsn.tw/ctf_writeup/20191012-hitconctfquals/#bounty-pl33z// From: Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (p. 43). Kindle Edition.log=[];for(let i=0;i<=0xff;i++){for(let j=0;j<=0xfff;j++){try {eval(`${String.fromCodePoint(i,j)}%$£234$`)log.push([i,j])}catch(e){}}}console.log(log)//[35,33],[47,47]
Caracteres de Nova Linha JS Válidos
//Javascript interpret as new line these chars:String.fromCharCode(10) //0x0aString.fromCharCode(13) //0x0dString.fromCharCode(8232) //0xe2 0x80 0xa8String.fromCharCode(8233) //0xe2 0x80 0xa8for (let j =0; j <65536; j++) {try {var cmd ='"aaaaa";'+String.fromCharCode(j) +'-->a.orange.ctf"';eval(cmd);} catch(e) {var err =e.toString().split('\n')[0].split(':')[0];if (err ==='SyntaxError'|| err ==="ReferenceError")continue;err =e.toString().split('\n')[0]}console.log(`[${err}]`,j,cmd);}//From: https://balsn.tw/ctf_writeup/20191012-hitconctfquals/#bounty-pl33z
Espaços JS Válidos na chamada de função
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (pp. 40-41). Kindle Edition.// Check chars that can be put in between in func name and the ()functionx(){}log=[];for(let i=0;i<=0x10ffff;i++){try {eval(`x${String.fromCodePoint(i)}()`)log.push(i)}catch(e){}}console.log(log)v//9,10,11,12,13,32,160,5760,8192,8193,8194,8195,8196,8197,8198,8199,8200,8201,8202,813 232,8233,8239,8287,12288,65279
Caracteres Válidos para Gerar Strings
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (pp. 41-42). Kindle Edition.// Check which pairs of chars can make something be a valid stringlog=[];for(let i=0;i<=0x10ffff;i++){try {eval(`${String.fromCodePoint(i)}%$£234${String.fromCodePoint(i)}`)log.push(i)}catch(e){}}console.log(log) //34,39,47,96//single quote, quotes, backticks & // (regex)
Surrogate Pairs BF
Esta técnica não será muito útil para XSS, mas pode ser útil para contornar as proteções do WAF. Este código Python recebe como entrada 2 bytes e procura pares de substituição que tenham o primeiro byte como o último byte do par de substituição alto e o último byte como o último byte do par de substituição baixo.
def unicode(findHex):for i inrange(0,0xFFFFF):H =hex(int(((i -0x10000) /0x400) +0xD800))h =chr(int(H[-2:],16))L =hex(int(((i -0x10000) %0x400+0xDC00)))l =chr(int(L[-2:],16))if(h == findHex[0]) and (l == findHex[1]):print(H.replace("0x","\\u")+L.replace("0x","\\u"))
javascript{}: Fuzzing de Protocólos
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (p. 34). Kindle Edition.log=[];let anchor =document.createElement('a');for(let i=0;i<=0x10ffff;i++){anchor.href =`javascript${String.fromCodePoint(i)}:`;if(anchor.protocol ==='javascript:') {log.push(i);}}console.log(log)//9,10,13,58// Note that you could BF also other possitions of the use of multiple chars// Test one optionlet anchor =document.createElement('a');anchor.href =`javascript${String.fromCodePoint(58)}:alert(1337)`;anchor.append('Click me')document.body.append(anchor)// Another way to test<ahref="javascript:alert(1337)">Test</a>
URL Fuzzing
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (pp. 36-37). Kindle Edition.// Before the protocola=document.createElement('a');log=[];for(let i=0;i<=0x10ffff;i++){a.href =`${String.fromCodePoint(i)}https://hacktricks.xyz`;if(a.hostname ==='hacktricks.xyz'){log.push(i);}}console.log(log) //0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32// Between the slashesa=document.createElement('a');log=[];for(let i=0;i<=0x10ffff;i++){a.href =`/${String.fromCodePoint(i)}/hacktricks.xyz`;if(a.hostname ==='hacktricks.xyz'){log.push(i);}}console.log(log) //9,10,13,47,92
HTML Fuzzing
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (p. 38). Kindle Edition.// Fuzzing chars that can close an HTML commentlet log=[];let div =document.createElement('div');for(let i=0;i<=0x10ffff;i++){div.innerHTML=`<!----${String.fromCodePoint(i)}><span></span>-->`;if(div.querySelector('span')){log.push(i);}}console.log(log)//33,45,62
O operador de decremento -- também é uma atribuição. Este operador pega um valor e o decrementa em um. Se esse valor não for um número, será definido como NaN. Isso pode ser usado para remover o conteúdo de variáveis do ambiente.
Truques de Funções
.call e .apply
O método .call de uma função é usado para executar a função.
O primeiro argumento que ele espera por padrão é o valor de this e se nada for fornecido, window será esse valor (a menos que modo estrito seja usado).
functiontest_call(){console.log(this.value); //baz}new_this={value:"hey!"}test_call.call(new_this);// To pass more arguments, just pass then inside .call()functiontest_call() {console.log(arguments[0]); //"arg1"console.log(arguments[1]); //"arg2"console.log(this); //[object Window]}test_call.call(null,"arg1","arg2")// If you use the "use strict" directive "this" will be null instead of window:functiontest_call() {"use strict";console.log(this); //null}test_call.call(null)//The apply function is pretty much exactly the same as the call function with one important difference, you can supply an array of arguments in the second argument:functiontest_apply() {console.log(arguments[0]); //"arg1"console.log(arguments[1]); //"arg2"console.log(this); //[object Window]}test_apply.apply(null, ["arg1","arg2"])
Funções de seta
Funções de seta permitem que você gere funções em uma única linha mais facilmente (se você as entender)
// Traditionalfunction (a){ return a +1; }// Arrow formsa => a +100;a => {a +100};// Traditionalfunction (a, b){ return a + b +1; }// Arrow(a, b) => a + b +100;// Tradictional no argslet a =4;let b =2;function (){ return a + b +1; }// Arrowlet a =4;let b =2;() => a + b +1;
Então, a maioria das funções anteriores é na verdade inútil porque não estamos salvando-as em nenhum lugar para salvar e chamá-las. Exemplo criando a função plusone:
// Traductionalfunctionplusone (a){ return a +1; }//Arrowplusone= a => a +100;
Bind function
A função bind permite criar uma cópia de uma função modificando o objeto this e os parâmetros dados.
//This will use the this object and print "Hello World"varfn=function ( param1, param2 ) {console.info( this, param1, param2 );}fn('Hello','World')//This will still use the this object and print "Hello World"var copyFn =fn.bind();copyFn('Hello','World')//This will use the "console" object as "this" object inside the function and print "fixingparam1 Hello"var bindFn_change =fn.bind(console,"fixingparam1");bindFn_change('Hello','World')//This will still use the this object and print "fixingparam1 Hello"var bindFn_thisnull =fn.bind(null,"fixingparam1");bindFn_change('Hello','World')//This will still use the this object and print "fixingparam1 Hello"var bindFn_this =fn.bind(this,"fixingparam1");bindFn_change('Hello','World')
Observe que usando bind você pode manipular o objeto this que será usado ao chamar a função.
Vazamento de código da função
Se você puder acessar o objeto de uma função, você pode obter o código dessa função.
functionafunc(){return1+1;}console.log(afunc.toString()); //This will print the code of the functionconsole.log(String(afunc)); //This will print the code of the functionconsole.log(this.afunc.toString()); //This will print the code of the functionconsole.log(global.afunc.toString()); //This will print the code of the function
Em casos onde a função não tem nome, você ainda pode imprimir o código da função de dentro:
O objeto Window permite acessar funções definidas globalmente, como alert ou eval.
// Some ways to access windowwindow.eval("alert(1)")framesglobalThisparentselftop //If inside a frame, this is top most window// Access window from documentdocument.defaultView.alert(1)// Access document from a node objectnode =document.createElement('div')node.ownerDocument.defaultView.alert(1)// There is a path property on each error event whose last element is the window<imgsrconerror=event.path.pop().alert(1337)>// In other browsers the method is<img srconerror=event.composedPath().pop().alert(1337)>// In case of svg, the "event" object is called "evt"<svg><image href=1 onerror=evt.composedPath().pop().alert(1337)>// Abusing Error.prepareStackTrace to get Window backError.prepareStackTrace=function(error, callSites){2 callSites.shift().getThis().alert(1337);3 };4 new Error().stack// From an HTML event// Events from HTML are executed in this contextwith(document) {with(element) {//executed event}}// Because of that with(document) it's possible to access properties of document like:<img srconerror=defaultView.alert(1337)><img srconerror=s=createElement('script');s.append('alert(1337)');appendChild(s)>
Ponto de interrupção no acesso ao valor
// Stop when a property in sessionStorage or localStorage is set/get// via getItem or setItem functionssessionStorage.getItem =localStorage.getItem=function(prop) {debugger;return sessionStorage[prop];}localStorage.setItem=function(prop, val) {debugger;localStorage[prop] = val;}
// Stop when anyone sets or gets the property "ppmap" in any object// For example sessionStorage.ppmap// "123".ppmap// Useful to find where weird properties are being set or accessed// or to find where prototype pollutions are occurringfunctiondebugAccess(obj, prop, debugGet=true){var origValue = obj[prop];Object.defineProperty(obj, prop, {get:function () {if ( debugGet )debugger;return origValue;},set:function(val) {debugger;origValue = val;}});};debugAccess(Object.prototype,'ppmap')
Acesso Automático ao Navegador para testar payloads
//Taken from https://github.com/svennergr/writeups/blob/master/inti/0621/README.mdconstpuppeteer=require("puppeteer");constrealPasswordLength=3000;asyncfunctionsleep(ms) {returnnewPromise((resolve) =>setTimeout(resolve, ms));}(async () => {constbrowser=awaitpuppeteer.launch();constpage=awaitbrowser.newPage();//Loop to iterate through different valuesfor (let i =0; i <10000; i +=100) {console.log(`Run number ${i}`);constinput=`${"0".repeat(i)}${realPasswordLength}`;console.log(` https://challenge-0621.intigriti.io/passgen.php?passwordLength=${input}&allowNumbers=true&allowSymbols=true×tamp=1624556811000`);//Go to the pageawaitpage.goto(`https://challenge-0621.intigriti.io/passgen.php?passwordLength=${input}&allowNumbers=true&allowSymbols=true×tamp=1624556811000`);//Call function "generate()" inside the pageawaitpage.evaluate("generate()");//Get node inner text from an HTML elementconstpasswordContent=awaitpage.$$eval(".alert .page-content",(node) => node[0].innerText);//Transform the content and print it in consoleconstplainPassword=passwordContent.replace("Your password is: ","");if (plainPassword.length!= realPasswordLength) {console.log(i,plainPassword.length, plainPassword);}awaitsleep(1000);}awaitbrowser.close();})();
