Protecting Users and Ads from Malware

Posted by Eric Davis, Head of Anti-Malvertising

As part of Cyber Security Awareness Month, we're highlighting cyber security tips and features to help ensure you're taking the necessary steps to protect your computer, website, and personal information. For general cyber security tips, check out our online security educational series or visit http://www.staysafeonline.org/.

At Google, we always aim to provide users with useful, relevant information. Readers of this blog know that we also work hard to detect malicious content on the web and protect users from harm. But did you know that we strive for the same level of relevance, and work equally as hard to protect users, in our online advertising business?

The mainstream media has recently picked up on the topic of malvertising (malware-infected advertising). Google's Anti-Malvertising Team works hard in this area and would like to take this time to share some important safety tips. We work closely with the Anti-Malware Team to identify trends and improve automated detection systems. We also educate users, develop policies and act as a liaison between the online security and online advertising communities.

Whether you're a web publisher who accepts ads on your website, or a home user who enjoys browsing the wide variety of advertising-supported content available on the web, we expect the resources below will help protect you from malvertising.

What is "Malvertising?"
"Malvertising" = malware + advertising. Haven't heard of it? The terminology may be new, but we can all understand the concept. Although malware distributors have attempted to spread malware through online ads for years, ever-improving prevention and detection methods have made it unlikely for most Internet users to have encountered a "bad ad" firsthand. However, it's important to make sure that you (and your computer) are properly prepared in case you encounter any source of malware on the web — whether it is an infected ad, a hacked site, a dangerous link, or someone who is pretending to be someone they're not.

Anti-Malvertising.com
We created Anti-Malvertising.com earlier this year as a resource for all members of the online ecosystem. Anti-Malvertising.com contains tips designed for publishers, ad operations teams, and Internet users to help protect their websites, networks, and computers.

Tips for Web Publishers: Know Who You're Working With, Perform Comprehensive QA, & Have a Plan in Place
Anti-Malvertising.com includes a custom search engine to help individual ad networks, publishers, and ad operations teams conduct quick background checks on prospective advertisers. It indexes a variety of independent, third party sites that track possible attempts to distribute malware through advertising. It is intended to be used as one of the steps in a publisher's background check process.

In some recent cases, infected ads that had already been caught and publicized by security researchers have remained active within some advertising systems. Anti-Malvertising.com's malvertising research engine makes it easier for the online advertising and security communities to share information and collaborate to help protect users from emerging threats.

For more detailed guidance on the following tips, visit http://www.anti-malvertising.com/tips-for-publishers

• Pay close attention to all agencies and advertisers with whom you work.
• Perform due diligence by thoroughly checking prospective partners' references and credentials.
• Perform comprehensive QA on all ad creatives.
• Protect your own computer and website from infection.
• Be aware that various ad networks and exchanges may have significantly different standards for the prevention and detection of malware. No automatic detection system, however robust, can substitute for your own vigilance. However, we strongly advise against exposing your site to harm by using networks or exchanges without strong anti-malware security measures in place.
• Ensure your Ad Operations team has an incident response plan in place (for guidance, visit http://www.anti-malvertising.com/tips-for-ad-operations).
  

Tips for Users: Protect Your Computer, Update Regularly, and Avoid Getting Tricked

• Make sure your browser, operating system, software and plugins are all updated regularly (enable auto-updates when possible).
• Be aware that malware can be disguised as antivirus/antispyware software in order to trick people into buying or downloading it. Fake (and harmful) software of this kind is known in the web security community as "rogue security software." How to avoid getting tricked? Always research a company's reputation before downloading its software or visiting its website, and be wary of unexpected warnings from products you haven't installed yourself. You can view a list of some legitimate free security scans at http://www.staysafeonline.org/content/free-security-check-ups.
• Exercise caution whenever you're prompted to download an email attachment, follow an instant message link, install a plug-in, or download an unfamiliar piece of software.
  

Protecting the Free Availability of Online Content
In addition to providing visibility to advertisers, revenue to publishers, and information to users, the online advertising business model also enables anyone with an Internet connection to access an entire world of content for free. By increasing our vigilance as a community, we can help to keep online ads safe and preserve the wide access to information that advertising enables.

Show Me the Malware!

written by Lucas Ballard, on behalf of the Anti-Malware, Anti-Malvertising, and Webmaster Tools teams

As part of Cyber Security Awareness Month, we're highlighting cyber security tips and features to help ensure you're taking the necessary steps to protect your computer, website, and personal information. For general cyber security tips, check out our online security educational series or visit http://www.staysafeonline.org/. To learn more about malware detection and site cleanup, visit the Webmaster Tools Help Center and Forum.

To help protect users against malware threats, Google has built automated scanners that detect malware on websites we've indexed. Pages that are identified as dangerous by these scanners are accompanied by warnings in Google search results, and browsers such as Google Chrome, Firefox, and Safari also use our data to show similar warnings to people attempting to visit suspicious sites.

While it is important to protect users, we also know that most of these sites are not intentionally distributing malware. We understand the frustration of webmasters whose sites have been compromised without their knowledge and who discover that their site has been flagged. We proactively offer help to these webmasters: we send email to site administrators when we encounter suspicious content, we provide a list of infected pages in Webmaster Tools, and we maintain a service that allows webmasters to notify us when they have cleaned their sites. Read more about this process in the previous post on this blog.

We're happy to announce that we've launched a feature that enables Google to provide even more detailed help to webmasters. Webmaster Tools now provides webmasters with samples of the malicious code that Google's automated scanners detected on their sites. These samples — which typically take the form of injected HTML tags, JavaScript, or embedded Flash files — are available in the "Malware details" Labs feature in Webmaster Tools. (UPDATE: The 'Malware details' feature graduated from Labs and is now part of the default Webmaster Tools interface. You can access it in the regular menu under 'Diagnostics'). Registered webmasters (registration is free) of infected sites do not need to specially enable the feature — they will find links to it on the Webmaster Tools dashboard. Webmasters will see a list of their pages that we found to be involved in malware distribution and samples of the malicious content that Google's scanners encountered on each infected page. In certain situations we can identify the underlying cause of the malicious code, and we'll provide these details when possible. We hope that the additional information will assist webmasters and help prevent their visitors from being exposed to malware.


Malware details for your site



Malware details for a particular page


While we're excited to offer this feature, we caution webmasters to use the tool only as a starting point in their site clean-up process. Google's scanners may not be able to provide malware samples in all cases, and the malware samples may not be a complete list of all the malware on the page. More importantly, we advise against simply removing the examples that are displayed in Webmaster Tools. If the underlying vulnerability is not identified and patched, it is likely that the site will be compromised again.

In addition to helping the webmasters of sites with malware warnings, this new detail is also designed to promote the general health of the web. In some cases, our automatic scanners find questionable content on a site but do not have enough data to add it to the malware list. The new "Malware details" feature will highlight these instances to webmasters early on to help them identify and address security vulnerabilities more quickly.

We hope you never have cause to use this feature, but if you do, it should help you quickly purge malware from your site and help protect its visitors. We plan to improve our algorithms in the upcoming months to provide even greater coverage, more accurate vulnerability identification, and faster delivery to webmasters.

The Malware Warning Review Process

written by Lucas Ballard and Ke Wang, Anti-Malware Team

As part of Cyber Security Awareness Month, Google's Anti-Malware Team is publishing a series of educational blog posts inspired by questions we've received from users. October is a great time to brush up on cyber security tips and ensure you're taking the necessary steps to protect your computer, website, and personal information. For general cyber security tips, check out our online security educational series or visit http://www.staysafeonline.org/. To learn more about malware detection and site cleanup, visit the Webmaster Tools Help Center and Forum.

Google's anti-malware efforts are designed to be helpful to both webmasters and website visitors. Google continuously scans our web index for pages that could be dangerous to site visitors. When we find such pages, we flag them as harmful in our search results, and also provide this data to several browsers so that users of these browsers will receive warnings directly. We undertake this process as part of our security philosophy: we believe that if we all work together to identify threats and stamp them out, we can make the web a safer place for everyone. While we believe these processes are important steps in helping to protect our users, we also understand the frustration felt by the webmasters of flagged sites. This is why we notify webmasters as soon as we discover that their sites have been compromised. Additionally, we provide webmasters with a tool to file a review once they have cleaned their site. The review process works as follows.

Part 1: The webmaster's job: The first step is site cleanup. The webmaster should remove all harmful content from the site. We realize that it can be tricky to find all the infections on a website, and webmasters should look thoroughly if the warning label persists. Keep in mind that if your site contains elements from another website that may have been compromised, it will remain flagged. This is because your site could still introduce harm to visitors. To prevent reinfection, the webmaster should also identify and fix the underlying software vulnerability that led to site compromise in the first place. For a guide on how to do this, visit stopbadware.org/home/security.

Once a webmaster has cleaned up the site, a Malware Review can be filed with Google's Webmaster Tools (please note that a Malware Review request is not the same as an Index Reinclusion request). The process for Malware Review is as follows:

1. Log in to Webmaster Tools.
2. From the Tool's home page click on the link to the site that is being flagged. This will bring you to the site's Dashboard.
3. There should be a large red banner across the top of the dashboard that says "This site may be distributing malware." Clicking on the link that says "More Details" expands the dashboard to reveal a list of pages on the site that were found to be malicious.
4. Below this list is a link that says "Request a review." A webmaster can fill out this form and click the "Request a review" button to initiate the review process.

More detailed instructions can be found here.


Part 2: Our job: Upon receiving a Malware Review request, an automated set of algorithms verifies that the site has been cleaned. These algorithms revisit a subset of both the malicious and non-malicious pages that were scanned when the site was originally flagged. Additionally, these algorithms test some pages that were not originally scanned. If none of the tested pages are found to be malicious, the site is deemed to be safe, and warnings are removed from search results. A typical appeal takes only several hours to complete, although in some cases the process may take up to one day.

In addition to processing appeal requests from webmasters, we also rescan compromised sites periodically.

We encourage webmasters of infected sites to quickly clean their web pages and proactively request reviews through Webmaster Tools. After the site has been thoroughly cleaned and reviewed, it will no longer show a warning on Google's search results pages or through the browsers making use of our data.

Malware Statistics Update

Posted by Niels Provos, Security Team

Every now and then people ask us for an update on the malware statistics we published in the All Your iFrames Point To Us blog post. We're glad to share this sort of data because we believe that collaboration and information sharing are crucial in driving anti-malware efforts forward. Here is a small update containing some interesting trends we've observed over the last 12 months.

Number of Entries on the Google Safe Browsing Malware List

As we mentioned in our Top-10 Malware Sites blog post, we have seen a large increase in the number of compromised sites since April. The number of entries on our malware list has more than doubled in one year, and we have seen periods in which 40,000 web sites were compromised per week. However, compared to infections associated with Gumblar and Martuz — two relatively large and well-known pieces of malicious code, many compromised web sites now point to hundreds of different domains. As these malware trends evolve, we're constantly improving our systems to better detect compromised web sites. The increase in compromised sites we observed may have also been influenced by our improved detection capabilities.

Search Results Containing a URL Labeled as Harmful

The above graph shows the percentage of daily queries that contain at least one search result that we labeled as harmful. In January 2008, more than 1.2% of all Google search queries contained at least one such result (you can review a graph of this data in the aforementioned All Your iFrames Point To Us post). Since then, there has been a downward trend to well below 1%. We noticed an increase around May 2009, and that growth may be due to the appearance of a larger number of compromised web sites. That said, it's encouraging that compared to last year, fewer search queries contain results to potentially harmful sites.

Users of Google search, Google Chrome, Mozilla Firefox and Apple Safari receive warnings when visiting sites we identify as potentially harmful. These warnings are produced by our Safe Browsing API, a technology that is freely available for webmasters to implement.

Ask the Google Anti-Malware Team

Posted by Fabrice Jaubert

The Google Anti-Malware engineering team knows you have many questions related to our scanning and flagging of infected sites, some with short and simple answers and some with more complex answers. The short-answer questions are already -- we hope -- adequately handled on the Webmaster Forums; now we want to do a better job at answering the more complex questions.

To this end, we have created a Google Moderator page for you to submit your questions, and to vote on other webmasters' questions. In two weeks (on Friday the 28th of August), we will close the page and select a few of the top-rated questions. Over the course of the next several weeks, we will do our best to answer each of these in a write-up, to be published here and to the Webmaster Malware Forum.

We hope to repeat this exercise (with a fresh Moderator page) in the fall to give you the opportunity to ask more questions.

Thank you, and see you on the Moderator page!

Improving web browser security

Posted by Chris Evans, Security Team

Malware is the source of a large number of reported security incidents on the Internet. Since Internet users can become infected in many different ways, the proliferation of malware is a very hard problem to solve. One part of the solution is to improve the robustness of web browsers such that security compromises due to browser bugs are minimized. We work hard to scrutinize our own code for potential vulnerabilities. We also contribute to research in this area with projects like the Browser Security Handbook and open source releases of the fuzzers involved in our software testing.

Some of you may have noticed that while working on Google Chrome, we have also discovered and responsibly reported a number of security issues in other browsers. Various scenarios lead us to report these bugs:

• Some browsers share code bases with Google Chrome, and we collaborate with those browser vendors.
• We develop generic fuzzers that are applicable to most browsers and that we want to share with others.
• We spend time analyzing behavior in different browsers, and we sometimes discover bugs in the process.
• It benefits our users and the Internet as a whole if we work collaboratively on better web browser security.

A few of the more interesting bugs we've researched recently include: this one in Opera uncovered by Michal Zalewski's <canvas> fuzzer; a HTTP 449 response code issue in IE found by Tavis Ormandy; contributions to Safari 4's security by Robert Swiecki, SkyLined, and Dean McNamee (and others); an XMLHttpRequest leak in Firefox discovered by Marius Schilder; and a cross-domain leak in Chrome / Safari (the two share a common base) unearthed by Chris Evans.

The collaboration works both ways. We'd like to thank the following browser vendors:
Microsoft for helping with SSL interactions with HTTP proxies, Mozilla for sharing fuzzers, and Apple for sharing and coordinating Webkit-based bugs.

Together as a security community, our combined efforts to find vulnerabilities in browsers, practice responsible disclosure, and get problems fixed before criminals exploit them help make the Internet an overall safer place for everyone. We'd also like to thank all those who have helped us by contributing to Google Chrome.

Password strength and account recovery options

Posted by Macduff Hughes, Engineering Director

There's been some discussion today about the security of online accounts, so we wanted to share our perspective. These are topics that we take very seriously because we know how important they are to our users. We run our own business on Google Apps, and we're highly invested in providing a high level of security in our products. While we can't discuss individual user or customer cases, we thought we'd try to clear up any confusion by taking some time to explain how account recovery works with various types of Google accounts and by revisiting some tips on how users can help keep their account data secure.

One of the more common requests for assistance that we receive from regular Gmail users is to help them regain access to their accounts after they have misplaced or forgotten their password. We know that it can be frustrating when you can't access your account, and we've worked hard to come up with a system designed to help our users regain access to their accounts as smoothly as possible while taking appropriate precautions to protect their account security. When you select a password as you create an account, we recommend that you also choose a security question and provide a secondary email address. Recently, we also added a field where you can input a mobile phone number to assist with later account recovery. We regularly provide tips about how you can choose good passwords and security questions, and we also share our best ideas for what to do when you can't access your account. It's important to keep your password, security question, and secondary email address up to date. It's not enough to just tell us your email address to try to change your password. The security question helps us identify you, but if you want to initiate a password reset, we'll only send that information to the secondary address or the mobile phone number you provide.

We handle password recovery differently for our Google Apps customers. There is no password recovery process for individual Google Apps users. Instead, users must communicate directly with their domain administrator to initiate password changes on their individual accounts. Earlier this year we added new password security tools for Google Apps that allow administrators to set password length requirements and view password strength indicators to identify sufficiently long passwords that may still not be strong enough. For businesses that desire additional authentication security, since 2006 we have supported SAML Single Sign On, a protocol that allows organizations to use two factor authentication solutions such as certificates, smartcards, biometrics, one time password devices, and other stronger tokens.

If you're a regular Gmail user and you haven't updated your account information in a while, we recommend you do so by visiting your Google Account settings page now.