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Some function such as _**file\_get\_contents(), fopen(), file(), md5\_file()** _ accept URLs as input that they will follow making **possible SSRF vulnerabilities** if the use can control the data:
```php
file_get_contents("http://127.0.0.1:8081");
fopen("http://127.0.0.1:8081", "r");
file("http://127.0.0.1:8081");
md5_file("http://127.0.0.1:8081");
```
### CRLF
Moreover, in some cases it might be even possible to send arbitrary headers via CRLF "vulnerabilities" in the previous functions:
```php
# The following will create a header called from with value Hi and
# an extra header "Injected: I HAVE IT"
ini_set("from", "Hi\r\nInjected: I HAVE IT");
file_get_contents("http://127.0.0.1:8081");
GET / HTTP/1.1
From: Hi
Injected: I HAVE IT
Host: 127.0.0.1:8081
Connection: close
# Any of the previously mentioned functions will send those headers
```
{% hint style="warning" %}
For more info about that CRLF vuln, check this bug [https://bugs.php.net/bug.php?id=81680\&edit=1](https://bugs.php.net/bug.php?id=81680\&edit=1)
{% endhint %}
Note that these function might have other methods to set arbitrary headers in requests, like:
```php
$url = "";
$options = array(
'http'=>array(
'method'=>"GET",
'header'=>"Accept-language: en\r\n" .
"Cookie: foo=bar\r\n" . // check function.stream-context-create on php.net
"User-Agent: Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.102011-10-16 20:23:10\r\n" // i.e. An iPad
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* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
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* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
