SPECIAL
REPORT:
Protect your media player
from podcasts
By Brian Livingston
It should be fun
and harmless to play podcasts — short radio and television programs that
download automatically from the Internet. But dumb programming mistakes in
popular media players can allow spyware to silently infect your PC while
an apparently innocent multimedia file is playing.
In the first
part of my special report on podcasts, published last
issue, I explained that applications designed for media downloading —
called "podcatchers" — can cheerfully save hacked media files or even
troublesome executable files to your hard disk.
In the second part
of my report, I'll explain today the steps you can take to protect
yourself.
Infected executable files, in this case, aren't actually
your most serious problem. Let's say a podcast you download happens to
really be, for example, a dot-exe file. If your podcatching
software downloaded the file earlier and you absent-mindedly try to play
it, your media player will probably do nothing. It'll just sit there,
waiting for you to load a file type it understands.
The real danger
occurs if your media player allows a "poisoned" audio or video file to
silently run commands or install other files.
You'd think media
players would support nothing but audio, video, and still images. But,
amazingly, these players have a history of letting multimedia files get
away with murder.
The good news is that playing podcasts on a
specialized MP3 player — such as an Apple iPod or a Creative Zen Micro —
probably won't infect these little devices. They run simple operating
systems and aren't full computers, so they're not attractive
targets.
The bad news is that, if you watch video podcasts or
listen to audio podcasts using Windows or a Pocket PC, any weaknesses in
your Microsoft or third-party media player can expose you to
infection.
If you have a broadband connection, in particular, your
PC is a valuable resource for hackers who'd love to install their spyware.
They can then show you pay-per-click pop-up ads, use your bandwidth to
quietly send millions of pieces of spam, or launch denial-of-service
attacks against Web sites.
The solution is to keep your media
player updated with the latest vendor patches. This can be a simple and
trouble-free task. Once your player is updated, you can relax and enjoy
podcasts safely.
In the following sections, I'll tell you how to
fix whichever media player you may use — Windows Media Player, iTunes,
QuickTime, RealPlayer, or Winamp.
|
 Windows Secrets
Newsletter Issue 59 —
2005.08.11
INTRODUCTION • Next
issue Sept. 15, no issue Aug. 25
TOP STORY • Protect your media player from podcasts • Update WMP to avoid surprises • iTunes isn't safe just because it's Apple • QuickTime can play more than videos • Music and movies can hack RealPlayer • Winamp falls victim to sneak MP3s
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Update Windows Media
Player to avoid surprises
Late in 2004, computer
experts noticed that a popular Windows Media Player video file was
actually a silent delivery mechanism infecting millions of PC users with
spyware.
On Jan. 3, 2005, security researcher Ben Edelman revealed
what was happening to people who played this video file in WMP. After
clicking the OK button on a single, legitimate-looking "browser update"
dialog box, "My computer quickly became contaminated with the most spyware
programs I had ever received in a single sitting," he said.
Edelman
counted an amazing total of 31 programs that had silently been installed,
without even displaying a license agreement. These included adware from
180solutions, CoolWebSearch, Ezula, ISTbar, and many other adware
companies, he said. (By the way, I reported on July
14 that Microsoft's AntiSpyware beta program, to the dismay of spyware
experts, has stopped recommending the removal of programs by 180solutions,
Ezula, and some other adware companies.)
How the trick
works: Media files that are played using recent versions of Windows
Media Player, such as 9.0 and 10.0, can invoke Microsoft's Digital Rights
Management system. This DRM scheme allows multimedia files, among other
things, to open a Web page and display information to the
user.
Allowing audio and video files to open new windows is not
such a good idea in the first place. Even worse, however, is how DRM was
implemented by Microsoft.
Left: Playing a video file
in Windows Media Player can launch a dialog box that looks official but
installs spyware. Enlarge
image in context
DRM-protected multimedia files, when
played in WMP, can make a dialog box appear, such as the one shown above
that Edelman diagnosed. (This image is reproduced with Edelman's
permission.) In this case, the dialog box tells the user to click the
Install button to get what was supposedly a Required Media Player
Version 10 Browser Update.
Most Windows users, of course, see
dialog boxes like this all the time. For example, legitimate audio and
video files commonly require the download of a particular
compressor-decompressor, or codec. That perfectly ordinary situation
displays a very similar codec-update dialog. (I discuss, below, a safe way
to update codecs.)
In the case shown above, the message does say
Security Warning, but so do many other alert boxes. It's very natural for
Windows users to click OK on boxes such as this one, and huge numbers of
people have done so. After all, the dialog box says the download is
required! (For details, see Edelman's original
report.)
Microsoft's response to the outcry over this
unacceptable behavior was pathetic. For at least a week, the company
initially said the misleading dialog boxes were using a "by-design
feature" of WMP, which wouldn't be changed. The company then reversed
course, telling eWeek
in January that a patch would be available by mid-February.
Patches
that allowed WMP 10 users to switch off the deceptive behavior were in
fact released by then. But no patches were made available for WMP 9, which
is used by more people, according to an April 14 eWeek article.
Microsoft
finally released security advisory 892313
and the related Knowledge Base article 892313
on May 10. These articles described the problem and linked to an update
for WMP 9 that had been posted a few days earlier.
Unfortunately,
the WMP 9 patch is available only for users of Windows 2000 and 2003, not
users of Windows 98 or Me. Worse, neither the advisory nor the KB article
tells WMP 9 and 10 users that they must change a setting to turn the
protection on after installing the upgrades. Finally, as far as I can
determine, neither Windows Update nor the newer Microsoft Update bothers
to inform users of the need for these upgrades.
What to do:
Users of Windows XP with Service Pack 2 (SP2) who also have Windows Media
Player 10 installed are not vulnerable to the problem. For everyone else,
I've put together the following steps to make you immune.
WMP is
"integrated" into Windows and you can't easily remove it. For this reason,
I urge you to upgrade WMP's components to the latest version available for
your OS, even if you never use it. Then apply patches as described in the
steps below. WMP 10 will run only on Windows XP. WMP 9 will run on Windows
98 SE, Me, 2000, and 2003 as well as XP.
Users of Windows
XP: First, if you don't have SP2 installed, I recommend that you
install it now, using the XP
SP2 page or the new Microsoft
Update (requires Internet Explorer). While you're at it, use Microsoft
Update to get the latest security patches for XP. Then, if you don't have
WMP 10, get it from Microsoft's download
center. Once WMP 10 is installed, read security advisory 892313
and install the update for WMP 10 using the link in KB article 892313.
Finally, read section
9.4 of Microsoft's WMP FAQ. Follow the instructions in bullet point 4
to turn off auto-acquisition. To do this in WMP, right-click the title
bar, then click Tools, Options, Privacy, then turn off Acquire licenses
automatically for protected content.
Users of Windows 2000
or 2003: First, use the new Microsoft
Update (requires IE) to get the latest security patches for your OS.
Then, upgrade to the latest version of WMP 9 using Microsoft's download
center. Once the updated WMP 9 is installed, read security advisory 892313
and install the update for WMP 9 using the link in KB article 892313.
Finally, read section
9.4 of Microsoft's WMP FAQ. Follow the instructions in bullet point 4
to turn off auto-acquisition. To do this in WMP, right-click the title
bar, then click Tools, Options, Privacy, then turn off Acquire licenses
automatically for protected content.
Users of Windows 98 SE
and Me: WMP 9 will run on these OS versions, but 98 SE and Me are so
old that Microsoft no longer supports them and I don't recommend them.
There's no patch for WMP 9 on these operating systems. If you have a PC
that's running 98 SE or Me, check whether it meets the hardware
requirements for XP using Microsoft's upgrade
center. If so, I urge you to upgrade to XP SP2 and WMP 10, even if you
have to pay money for a retail copy of XP.
All users:
Upgrading to the latest Windows security patches, which I recommend above
as step one, eliminates other security holes that affect WMP. For example,
being current with all patches stops WMP 9 from being infected by poisoned
PNG images, as described in MS05-009.
Also, Windows Update may already have installed patch 828026, which dates
back to September 2003. Administrators should use the three Registry
values described in the related KB article 828026
to stop WMP 9 from responding to URL script commands.
Note that
even taking the steps above may allow some media files to display dialog
boxes, which you must take care to answer correctly. As far as I'm
concerned, no video is important enought to answer Yes to any dialog box a
strange file opens, if WMP is the media player. (If you need an updated
codec, download it separately from a legitimate source, such as the ones
recommended by Microsoft in "How
do I find a codec?")
If you're running XP SP1 or higher or 2000
SP3 or higher, you can restrict access to WMP, although you can't easily
remove it. You do this using Windows' Set Program and Access
Defaults feature. Follow the instructions in section
2.4 of the WMP FAQ.
By the way, don't bother using KB 190990,
entitled "How to determine the version of Windows Media Player," to
determine your version of WMP. Despite being revised as recently as Mar.
24, 2005, the article shows the wrong current version numbers for WMP 9
and 10.
After you've upgraded and patched WMP, you may also wish to
install one of the third-party media players mentioned later in this
article. Let the new player associate multimedia file extensions with
itself so WMP never runs. That's the best you can do to keep audio and
video files from automatically launching WMP. When security holes are
discovered in the future, my guess is that other vendors will fix their
problems quicker than Microsoft will. iTunes isn't safe just because
it's Apple
Apple software doesn't suffer from security flaws as often as
Microsoft's does, but problems aren't unheard of. You need to stay abreast
of Apple updates, especially for its popular iTunes media program, just as
you do with Windows apps.
A flaw in iTunes was announced by Apple
as recently as May 9, 2005. The problem allows a hacked MPEG4 file
(.mp4) to silently install a Trojan horse on a computer. This
wouldn't affect an iPod or other specialized MP3 player. Nor would it
likely affect Apple's OS X operating system, which protects users from
installing software unknowingly. But it would be a big problem in Windows,
which by default runs with administrator privileges all the time, allowing
viruses to quietly install themselves.
Fortunately, Apple released
an upgrade, iTunes version 4.8, on May 9 to correct the problem on Windows
2000 and XP and OS X 10.2.8 or higher. Even better, Apple released iTunes
version 4.9 on June 28, which is the first version that supports
podcasting. You should upgrade iTunes to 4.9 immediately.
What
to do: First, read the description of the MPEG4 problem provided by SANS
and Apple.
Then, upgrade to iTunes 4.9 using Apple's download
page. QuickTime can play more
than videos
QuickTime is another Apple program, this one primarily used
to display short videos. The application runs on both Windows and Mac and
often comes preinstalled on PCs. It's also widely downloaded by people who
want to view movie trailers provided by Hollywood studios and other
content.
QuickTime was found in September 2004 to be hackable if it
was used to display, of all things, a still-image bitmap file
(.bmp). If you happened to load a poisoned bitmap, it could
silently take over your PC while the image was being displayed as though
nothing was wrong.
Apple released QuickTime 6.5.2 on Oct. 27, 2004,
to correct the problem. Since that date, it's released QuickTime 7.0. But
that version was found to allow media files to send data from your
computer back to a hacker's Web server. The company released QuickTime
7.0.1 on May 31, 2005, to patch this.
What to do: Read
Apple's descriptions of the problems corrected by QuickTime 6.5.2
and 7.0.1.
Then upgrade to QuickTime 7.0.1 using Apple's download
page. Music and movies can
hack RealPlayer
RealPlayer is one of the most popular media
players on the market, with hundreds of millions of downloads of its free
player and more than 2 million paying subscribers, according to a company
statement.
But RealPlayer and other products made by
RealNetworks have had a troubled history with security holes and privacy
issues. The company lists on its security page more than a dozen patches
that have been required for its media products, including RealPlayer and
RealOne Player, in the past 2-1/2 years.
In addition, RealNetworks'
software raises security issues for both companies and individuals.
RealPlayer and RealOne Player are configured by default with
Internet-access features that allow RealNetworks and its partners, such as
NASCAR and CNN, to install additional software, according to WatchGuard
Technologies.
Most recently, RealNetworks released patches for
its software — including RealPlayer, realOne Player, RealPlayer
Enterprise, and Rhapsody — on June 23, 2005. These programs, if unpatched,
can let hackers access a PC if the user plays a hacked MP3 audio file or
AVI video file, or even visits a Web site that plays multimedia
content.
What to do: Read the descriptions of the latest
security hole provided by eEye
Digital Security and RealNetworks.
Then review any patches that may apply to you on RealNetworks' security
page.
Finally, upgrade any RealNetworks software you may have
to the latest version that's safe. For example, RealNetworks' June 23
bulletin says these versions are not at risk: RealPlayer 10.5 (build
6.0.12.1212) and Rhapsody 3 (build 0.1141). Winamp falls victim to sneaky MP3s
Winamp
is such a widely used media player that it's listed as the 32nd most
popular file at CNET's Download.com.
Unfortunately, like the other player apps, Winamp, too, has had its share
of programming blunders that exposed users to danger.
In the latest
case, merely playing an MP3 file in Winamp can cause hacker code to
silently run. This can potentially plant a Trojan horse on a computer,
according to a July 14 analysis by a security research group in Croatia
named LSS (Laboratorij za Sustave i Signale).
Winamp released a new
version on July 19 that fixes the flaw.
What to do: Read the
analysis by LSS,
then upgrade to Winamp 5.094 using Winamp's download
page. C'mon, get it
together, developers
Of all of the Windows applications we use,
media players that simply play audio or video clips should be risk-free.
It isn't asking too much for developers of these programs to subject them
to thorough security audits and neutralize any possible
threats.
Enjoying podcasts should be a simple matter that doesn't
expose users to serious risks. We're not there yet, so — until that day
comes — you need to give your media player periodic patches in order to
use podcasts safely.
You might think that a podcaster would never
risk losing audience share by including a virus in a regularly scheduled
show. But a podcaster's PC might inadvertently get infected, adding a
hidden virus to a file without anyone noticing until it had gone out to
thousands of people.
In addition, viruses these days don't seek to
erase a PC's hard drive. Instead, they aim to quietly take over the PC's
bandwidth, and big dollars are at stake. Podcasters have already received
financial offers to distribute adware within podcatching software,
according to a public
warning by Nick Bradbury, the developer of FeedDemon. We all have to
keep our guard up against this threat.
To send us more information
about podcasting, or to send us a tip on any other subject, visit WindowsSecrets.com/contact.
You'll receive a gift certificate for a book, CD, or DVD of your choice if
you send us a comment that we print.
Brian Livingston is
editor of the Windows Secrets Newsletter and the coauthor of Windows
2000 Secrets, Windows
Me Secrets, and eight other books.
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