Exploit for anti-xss

Name: Exploit for anti-xss
Rating: 5 (261 reviews)
2026-01-06 | CVSS 5.8
## https://sploitus.com/exploit?id=18B18E8B-AFB9-568E-9A10-F97E158D425B
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# :secret: AntiXSS

"Cross-site scripting (XSS) is a type of computer security vulnerability typically found in Web applications. XSS enables 
attackers to inject client-side script into Web pages viewed by other users. A cross-site scripting vulnerability may be 
used by attackers to bypass access controls such as the same origin policy. Cross-site scripting carried out on websites 
accounted for roughly 84% of all security vulnerabilities documented by Symantec as of 2007." - http://en.wikipedia.org/wiki/Cross-site_scripting

### DEMO:
[http://anti-xss-demo.suckup.de/](http://anti-xss-demo.suckup.de/)

### NOTES:
1) Use [filter_input()](http://php.net/manual/de/function.filter-input.php) - don't use GLOBAL-Array (e.g. $_SESSION, $_GET, $_POST, $_SERVER) directly

2) Use [html-sanitizer](https://github.com/tgalopin/html-sanitizer) or [HTML Purifier](http://htmlpurifier.org/) if you need a more configurable solution

3) Add "Content Security Policy's" -> [Introduction to Content Security Policy](http://www.html5rocks.com/en/tutorials/security/content-security-policy/)

4) DO NOT WRITE YOUR OWN REGEX TO PARSE HTML!

5) READ THIS TEXT -> [XSS (Cross Site Scripting) Prevention Cheat Sheet](https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.md)

6) TEST THIS TOOL -> [Zed Attack Proxy (ZAP)](https://github.com/zaproxy/zaproxy)

### Install via "composer require"
```shell
composer require voku/anti-xss
```

### Usage:

```php

use voku\helper\AntiXSS;

require_once __DIR__ . '/vendor/autoload.php'; // example path

$antiXss = new AntiXSS();
```

Example 1: (HTML Character)

```php
$harm_string = "Hello, i try to alert('Hack'); your site";
$harmless_string = $antiXss->xss_clean($harm_string);

// Hello, i try to alert&#40;'Hack'&#41;; your site
```

Example 2: (Hexadecimal HTML Character)

```php
$harm_string = "";
$harmless_string = $antiXss->xss_clean($harm_string);
    
// 
```
    
Example 3: (Unicode Hex Character)

```php
$harm_string = "CLICK";
$harmless_string = $antiXss->xss_clean($harm_string);
    
// CLICK
```

Example 4: (Unicode Character)

```php
$harm_string = "CLICK";
$harmless_string = $antiXss->xss_clean($harm_string);
    
// CLICK
```

Example 5.1: (non Inline CSS)

```php
$harm_string = '';
$harmless_string = $antiXss->xss_clean($harm_string);

// 
```

Example 5.2: (with Inline CSS)

```php
$harm_string = '';
$antiXss->removeEvilAttributes(array('style')); // allow style-attributes
$harmless_string = $antiXss->xss_clean($harm_string);

// 
```

Example 6: (check if an string contains a XSS attack)

```php
$harm_string = "\x3cscript src=http://www.example.com/malicious-code.js\x3e\x3c/script\x3e";
$harmless_string = $antiXss->xss_clean($harm_string);

// 

$antiXss->isXssFound(); 

// true
```

Example 7: (allow e.g. iframes)

```php
$harm_string = "";

$antiXss->removeEvilHtmlTags(array('iframe'));

$harmless_string = $antiXss->xss_clean($harm_string);

// 
```


### Unit Test:

1) [Composer](https://getcomposer.org) is a prerequisite for running the tests.

```
composer install
```

2) The tests can be executed by running this command from the root directory:

```bash
./vendor/bin/phpunit
```

## AntiXss methods

addDoNotCloseHtmlTags
addEvilAttributes
addEvilHtmlTags
addNeverAllowedCallStrings
addNeverAllowedJsCallbackRegex
addNeverAllowedOnEventsAfterwards
addNeverAllowedRegex
addNeverAllowedStrAfterwards
isXssFound
removeDoNotCloseHtmlTags
removeEvilAttributes
removeEvilHtmlTags
removeNeverAllowedCallStrings
removeNeverAllowedJsCallbackRegex
removeNeverAllowedOnEventsAfterwards
removeNeverAllowedRegex
removeNeverAllowedStrAfterwards
setReplacement
setStripe4byteChars
xss_clean


## addDoNotCloseHtmlTags(string[] $strings): $this
↑
Add some strings to the "_do_not_close_html_tags"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addEvilAttributes(string[] $strings): $this
↑
Add some strings to the "_evil_attributes"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addEvilHtmlTags(string[] $strings): $this
↑
Add some strings to the "_evil_html_tags"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addNeverAllowedCallStrings(string[] $strings): $this
↑
Add some strings to the "_never_allowed_call_strings"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addNeverAllowedJsCallbackRegex(string[] $strings): $this
↑
Add some strings to the "_never_allowed_js_callback_regex"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addNeverAllowedOnEventsAfterwards(string[] $strings): $this
↑
Add some strings to the "_never_allowed_on_events_afterwards"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addNeverAllowedRegex(string[] $strings): $this
↑
Add some strings to the "_never_allowed_regex"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## addNeverAllowedStrAfterwards(string[] $strings): $this
↑
Add some strings to the "_never_allowed_str_afterwards"-array.

**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## isXssFound(): bool|null
↑
Check if the "AntiXSS->xss_clean()"-method found an XSS attack in the last run.

**Parameters:**
__nothing__

**Return:**
- `bool|null Will return null if the "xss_clean()" wasn't running at all.`

--------

## removeDoNotCloseHtmlTags(string[] $strings): $this
↑
Remove some strings from the "_do_not_close_html_tags"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeEvilAttributes(string[] $strings): $this
↑
Remove some strings from the "_evil_attributes"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeEvilHtmlTags(string[] $strings): $this
↑
Remove some strings from the "_evil_html_tags"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeNeverAllowedCallStrings(string[] $strings): $this
↑
Remove some strings from the "_never_allowed_call_strings"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeNeverAllowedJsCallbackRegex(string[] $strings): $this
↑
Remove some strings from the "_never_allowed_js_callback_regex"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeNeverAllowedOnEventsAfterwards(string[] $strings): $this
↑
Remove some strings from the "_never_allowed_on_events_afterwards"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeNeverAllowedRegex(string[] $strings): $this
↑
Remove some strings from the "_never_allowed_regex"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## removeNeverAllowedStrAfterwards(string[] $strings): $this
↑
Remove some strings from the "_never_allowed_str_afterwards"-array.



WARNING: Use this method only if you have a really good reason.


**Parameters:**
- `string[] $strings`

**Return:**
- `$this`

--------

## setReplacement(string $string): $this
↑
Set the replacement-string for not allowed strings.

**Parameters:**
- `string $string`

**Return:**
- `$this`

--------

## setStripe4byteChars(bool $bool): $this
↑
Set the option to stripe 4-Byte chars.



INFO: use it if your DB (MySQL) can't use "utf8mb4" -> preventing stored XSS-attacks


**Parameters:**
- `bool $bool`

**Return:**
- `$this`

--------

## xss_clean(string|string[] $str): string|string[]
↑
XSS Clean



Sanitizes data so that "Cross Site Scripting" hacks can be
prevented. This method does a fair amount of work but
it is extremely thorough, designed to prevent even the
most obscure XSS attempts. But keep in mind that nothing
is ever 100% foolproof...




Note: Should only be used to deal with data upon submission.
  It's not something that should be used for general
  runtime processing.


**Parameters:**
- `TXssCleanInput $str input data e.g. string or array of strings`

**Return:**
- `string|string[]`

--------


### Support

For support and donations please visit [Github](https://github.com/voku/anti-xss/) | [Issues](https://github.com/voku/anti-xss/issues) | [PayPal](https://paypal.me/moelleken) | [Patreon](https://www.patreon.com/voku).

For status updates and release announcements please visit [Releases](https://github.com/voku/anti-xss/releases) | [Twitter](https://twitter.com/suckup_de) | [Patreon](https://www.patreon.com/voku/posts).

For professional support please contact [me](https://about.me/voku).

### Thanks

- Thanks to [GitHub](https://github.com) (Microsoft) for hosting the code and a good infrastructure including Issues-Managment, etc.
- Thanks to [IntelliJ](https://www.jetbrains.com) as they make the best IDEs for PHP and they gave me an open source license for PhpStorm!
- Thanks to [Travis CI](https://travis-ci.com/) for being the most awesome, easiest continous integration tool out there!
- Thanks to [StyleCI](https://styleci.io/) for the simple but powerfull code style check.
- Thanks to [PHPStan](https://github.com/phpstan/phpstan) && [Psalm](https://github.com/vimeo/psalm) for relly great Static analysis tools and for discover bugs in the code!

### License
[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fvoku%2Fanti-xss.svg?type=large)](https://app.fossa.io/projects/git%2Bgithub.com%2Fvoku%2Fanti-xss?ref=badge_large)