Vulnerability in the PDF distiller of the BlackBerry Attachment Service for the BlackBerry Enterprise Server

Looks like there has been another vulnerability discovered in the BlackBerry Enterprise Server PDF distiller of the BlackBerry Attachment Service.

Looks like there has been another vulnerability discovered in the BlackBerry Enterprise Server PDF distiller of the BlackBerry Attachment Service. This vulnerability is scoring 7.8 on the CVSS scale, so it is a high risk vulnerability.  You should apply the patch to your BES server ASAP.

See for the details from RIM.

If you haven’t already done so, you really should have the attachment service running in a segmented network in order to prevent the spread of malware. The PDF distiller has required quite a few patches in the past few years and is, in my opinion, the weakest point in the whole BES architecture.  See the BlackBerry technical notes on how to achieve segmentation here.

VLC media player auto-update and vulnerability

Secunia has published an advisory about new vulnerabilities found in VLC Media Player.

I just picked up an advisory from Secunia about VLC Media Player vulnerabilities. There are 9 vulnerabilities. Three are related to A/52, DTS and MPEG audio decoders. Three are about the AVI, ASF and Matroska demuxer. The other three are about the XSPF playlist, the ZIP and RTPM implementation.

Successful exploitation of the vulnerabilities may allow execution of arbitrary code, but requires that the user is tricked into opening a specially crafted file.

There is no CVE Reference and unfortunately cannot figure out a CVSS score.  You can find the original advisory (VideoLAN-SA-1003) here:

There are two interesting things about this one.  One, as of right now (April 25, 2010 at 22:39 GMT-6), the fixed version for Windows (1.0.6) is still not available on the Video LAN web site.  That’s a bit unusual because, typically, the vendor likes to make sure the patch/updated version of the vulnerable software is available before publishing the vulnerability on their on web site.  The second thing that’s interesting is that the auto-update does not seem to work in my installed version (1.0.1).

I thought that maybe I had a problem in my home LAN that caused the auto-update to fail.  I fired up Wireshark and did a quick sniff of the traffic when trying to get VLC to update.  I used the Follow TCP Stream feature and it was quickly apparent that the problem wasn’t with me at all.  The GET that VLC sent got a 206 Partial Content

HTTP/1.1 206 Partial Content
Content-Type: text/plain
Accept-Ranges: bytes
ETag: “3280753111”
Last-Modified: Mon, 01 Feb 2010 23:15:18 GMT
Content-Range: bytes 0-485/486
Content-Length: 486
Date: Mon, 26 Apr 2010 04:24:08 GMT
Server: lighttpd/1.4.19

Due to a bug in the update feature of your on of VLC, the automatic download of the new VLC will fail.

You have to download VLC 1.0.5 from VideoLAN’s website:

VLC 1.0.5 is a minor release of 1.0.x version of VLC. It fixes a few bugs, updates the codecs and the compiler for Windows, and should improve decoding speed. It also improves and update many translations.

Well, might as well download 1.0.5 for now and use the auto-update to check the 1.0.6 fix.

Disection of a web based infection

This post describes how compromised web sites try to infect your pc.

Gone are the days where you actually had to convince someone to open your malicious e-mail attachment to get malicious software installed. Now all you need is to browse a compromised web site and you can become a victim in a matter of seconds. This post will dissect the home page of such a web site and explain the different ways that bad guys are trying to install their malicious software onto your computer.

I was alerted to this compromised web site when our anti-virus console sent me an e-mail because it blocked a trojan on a user’s machine. This e-mail also included the URL of the compromised web site. The trojan is known as JS/Obfuscated by McAfee or JS.Obfuscated.Gen by Bit Defender. The anti-virus actually is able to detect the way the code on the web page has been obfuscated by the author.  This web page only got a 12.83% coverage amongst 39 different AV engines according to Virus Total.  I can only hope that the AV that did not catch that compromised web page will catch whatever the web page will download on the user’s computer before it causes real damage.

You would think that it would be easy to convince the owner of the web site to take action.  Unfortunately, it is not so.  I phoned them personally on Wednesday, Feb. 11.  I actually got a call back on Tuesday, Feb. 17.  I gave the details to the web master.  As of right now (Feb. 21), the site is still has the malicious JavaScript on its home page.  The site is at www dot airdrietrailer dot com and you should not browse it with Internet Explorer on Windows.  You are likely to get infected (especially if you do not keep up with patches).  I took a closer look at the malicious code and it tries to infect you through multiple attack vector, but those are specifically targeting IE.  The nice lady at Airdri Trailer Sales told me that she had already received calls from other people also telling her that their web site is infecting people, but their webmaster could not find what the problem was.

Here is a quick summary of how the infection works:

  1. The web site is somehow compromised and web page(s) modified to inject iFrame into each page on the site.
  2. A user browse the web site, the injected JavaScript code is executed, creating the iFrame which connect to a malicious site to download more code.
  3. The downloaded code is executed and tries multiple attack vectors in order to write to your hard drive.  If one of those vulnerabilities work, a payload is downloaded and executed on your computer.

And voila!  You have been p0wned.

Dissecting the attack

The malicious code is tacked at the bottom of the web page. The code is in two <script></script> blocks.  It is obfuscated by having a bunch of gibberish assigned to variables.  There is actually a bit of code visible in that gibberish, just enough to remove the obfuscation, which is rather simple.  Using the Malzilla tool, it makes it easy to see the code.  The first block reveals how it will de-obfuscate the code.  There are four block of codes that will be de-obfuscated by doing a string substition.  Here are some of the string that are replaced.

  1. Replace aHM with a % character
  2. Replace Zm with the D character
  3. Replace ouG with a % character
  4. Replace tr4 with a 3 character
  5. Replace %P5 with a 2 character
  6. there are more such substitions

All of those strings are then unescaped, and passed to the eval() function to be executed.  That’s where the real action is.

  1. The first block inserts a <BODY> </BODY> and a <DIV> tag into the web page if it finds that the body is empty.
  2. The second block gets a pointer to that DIV and saves it to a variable.  As well, it creates an iFrame element and sets it to a size of 1×1 and sets the source to point to a malicious web site (store16 dot looneytoons dot cc).  Doing a whois on that site reveals that it is a legitimate site registered by Warner Brothers.  Although there is a web server there, it does not return anything as of right now.
  3. Finally, the third block set the iFrame to hidden, gives it an id and appends it to the DIV created in the first block of code.

Since the iframe src attribute is pointing to malicious site, it populates itself with new HTML wich includes more JavaScript.  At that point, the code tries a few number of things in order to gain access to the operating system to enable to write files to your hard drive.  In fact, some of the code looks very much like it was borrowed from the Metasploit framework.  Here are all of the attack vectors that this code tries to exploit:

  1. Flash ActiveX if the version less than 9.0.124
  2. Adobe Reader
  3. Microsoft Office snapshot viewer ActiveX exploit (MS08-041 will protect you)
  4. AOL SB.SuperBuddy ActiveX code found in AOL Client Software 9.0 Security
  5. QuickTime
  6. Microsoft DirecAnimation ActiveX (MS06-067 will protect you)
  7. An oldie but goodie, Microsoft DDS Library Shape Control which was part of Visual Studio 2002 (MS05-052 will protect you)
  8. Windows Sell Remote Code Execution Vulnerability (MS06-57 will protect you)

Bottom line, if you are up to date on patches, you will not have problems.  The trick is to update not only Windows, but all your software you have on your computer.  Not so easy as most people do not really know what actually have installed over time.  The best thing you can do is to visit Secunia Software Scanning and use their scanner.  It will tell you all the software you have installed that requires updates.  If you actually download and install their software, it will keep track of what you have and let you know when there are new updates.

I do have the JavaScript saved, let me know if you would like to see it.

Time to patch your printers

HP revealed a new vulnerability that a directory traversal issue in the web admin interface allows remote user to view files on the printers. Should you start including printers in your patching policies? Here are some things you should do to protect yourself.

This might surprise some, but printers need patching too.  The rule of thumb you should use is if it has an IP address, then it can be vulnerable and will most likely require a patch at some point in time.

SANS handler’s diary has just published such a story – Time to patch your HP printers.  The actual HP bulletin is here.  Looks like PC Advisor also picked up the story.

The easiest way to do the firmware upgrade is to use HP’s Web Jetadmin.  Using Web Jetadmin, you can discover all your printers on your LAN and remotely do firmware upgrades.

Although this vulnerability only allows the bad guys to access any files on the printer (and therefore view previously printed documents), I can foresee printers being used as a staging point for more serious things.  The reason is that printers have not received the same amount of scrutiny that workstations/serves have and most likely are softer targets.  As well, printers do not run anti-virus or other kind of defensive software.  So what should you do?  Here are a few things that will harden your printers:

  1. Use a central management console like Web Jetadmin.  This will allow you to discover any new printers added and to easily deploy the latest firmware.
  2. Keep up with the firmware releases.  This is probably a difficult one to do, especially if you use printers from a number of vendors.  You should at least do a round of patching once a year.
  3. Scan your printers for vulnerabilities.  Make sure to use a tool that can differentiate between a printer device and a workstation.  If it doesn’t, scanning can lead to lockups and rebooting of your printers.  Not so good if it’s in the middle of printing a big color job by your boss.  Nessus scanner is one such scanner.  Be warned that scanning your printer will probably cause it to print a few pages.

If anyone else has anything else that they do to harden their printers, please use the comments below.