//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$`)log.push([i,j])}catch(e){}}}console.log(log)//[35,33],[47,47]
유효한 JS 새 줄 문자
//Javascript interpret as new line these chars:String.fromCharCode(10) //0x0aString.fromCharCode(13) //0x0dString.fromCharCode(8232) //0xe2 0x80 0xa8String.fromCharCode(8233) //0xe2 0x80 0xa8for (let j =0; j <65536; j++) {try {var cmd ='"aaaaa";'+String.fromCharCode(j) +'-->a.orange.ctf"';eval(cmd);} catch(e) {var err =e.toString().split('\n')[0].split(':')[0];if (err ==='SyntaxError'|| err ==="ReferenceError")continue;err =e.toString().split('\n')[0]}console.log(`[${err}]`,j,cmd);}//From: https://balsn.tw/ctf_writeup/20191012-hitconctfquals/#bounty-pl33z
유효한 JS 공백 함수 호출에서
// 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${String.fromCodePoint(i)}()`)log.push(i)}catch(e){}}console.log(log)v//9,10,11,12,13,32,160,5760,8192,8193,8194,8195,8196,8197,8198,8199,8200,8201,8202,813 232,8233,8239,8287,12288,65279
문자열 생성을 위한 유효한 문자
// Heyes, Gareth. JavaScript for hackers: Learn to think like a hacker (pp. 41-42). Kindle Edition.// Check which pairs of chars can make something be a valid stringlog=[];for(let i=0;i<=0x10ffff;i++){try {eval(`${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
이 기술은 XSS에는 그다지 유용하지 않지만 WAF 보호를 우회하는 데 유용할 수 있습니다. 이 파이썬 코드는 2바이트를 입력으로 받아들이고, 첫 번째 바이트가 하이 서러게이트 쌍의 마지막 바이트이고 마지막 바이트가 로우 서러게이트 쌍의 마지막 바이트인 서러게이트 쌍을 검색합니다.
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{}: 프로토콜 퍼징
// 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 퍼징
// 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 퍼징
// 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
감소 연산자 --는 또한 할당입니다. 이 연산자는 값을 가져온 다음 1만큼 감소시킵니다. 그 값이 숫자가 아닌 경우 NaN으로 설정됩니다. 이는 환경에서 변수의 내용을 제거하는 데 사용될 수 있습니다.
함수 트릭
.call 및 .apply
함수의 .call 메서드는 함수를 실행하는 데 사용됩니다.
기본적으로 기대하는 첫 번째 인수는 this의 값이며, 아무것도 제공되지 않으면 **window**가 그 값이 됩니다(단, **strict mode**가 사용되지 않는 한).
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"])
화살표 함수
화살표 함수를 사용하면 함수를 한 줄로 더 쉽게 생성할 수 있습니다(이해한다면).
// 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;
그래서 이전의 대부분 함수는 실제로 쓸모가 없습니다. 왜냐하면 우리는 그것들을 저장하거나 호출할 곳이 없기 때문입니다. 예를 들어 plusone 함수를 생성하는 것입니다:
// Traductionalfunctionplusone (a){ return a +1; }//Arrowplusone= a => a +100;
Bind function
bind 함수는 this 객체와 주어진 매개변수를 수정하여 함수의 복사본을 생성할 수 있게 해줍니다.
//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')
**bind**를 사용하면 함수 호출 시 사용될 this 객체를 조작할 수 있습니다.
함수 코드 유출
함수의 객체에 접근할 수 있다면 해당 함수의 코드를 얻을 수 있습니다.
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
이름이 없는 function의 경우, 내부에서 function code를 여전히 출력할 수 있습니다:
Window 객체는 alert 또는 eval과 같은 전역적으로 정의된 함수에 접근할 수 있게 해줍니다.
// 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)>
값 접근 시 중단점
// 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')
페이로드 테스트를 위한 자동 브라우저 접근
//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();})();
