Gmail security and recent phishing activity

Posted by Chris Evans

We've seen some speculation recently about a purported security vulnerability in Gmail and the theft of several website owners' domains by unauthorized third parties. At Google we're committed to providing secure products, and we mounted an immediate investigation. Our results indicate no evidence of a Gmail vulnerability.

With help from affected users, we determined that the cause was a phishing scheme, a common method used by malicious actors to trick people into sharing their sensitive information. Attackers sent customized e-mails encouraging web domain owners to visit fraudulent websites such as "google-hosts.com" that they set up purely to harvest usernames and passwords. These fake sites had no affiliation with Google, and the ones we've seen are now offline. Once attackers gained the user credentials, they were free to modify the affected accounts as they desired. In this case, the attacker set up mail filters specifically designed to forward messages from web domain providers.

Several news stories referenced a domain theft from December 2007 that was incorrectly linked to a Gmail CSRF vulnerability. We did have a Gmail CSRF bug reported to us in September 2007 that we fixed worldwide within 24 hours of private disclosure of the bug details. Neither this bug nor any other Gmail bug was involved in the December 2007 domain theft.

We recognize how many people depend on Gmail, and we strive to make it as secure as possible. At this time, we'd like to thank the wider security community for working with us to achieve this goal. We're always looking at new ways to enhance Gmail security. For example, we recently gave users the option to always run their entire session using https.

To keep your Google account secure online, we recommend you only ever enter your Gmail sign-in credentials to web addresses starting with https://www.google.com/accounts, and never click-through any warnings your browser may raise about certificates. For more information on how to stay safe from phishing attacks, see our blog post here.

OAuth for Secure Mashups

Posted by Eric Sachs, Senior Product Manager, Google Security

A year ago, a number of large and small websites announced a new open standard called OAuth. This standard is designed to provide a secure and privacy-preserving technique for enabling specific private data on one site to be accessed by another site. One popular reason for that type of cross-site access is data portability in areas such as personal health records (such as Google Health or Microsoft Healthvault), as well as social networks (such as OpenSocial enabled sites). I originally became involved in this space in the summer of 2005, when Google started developing a feature called AuthSub, which was one of the pre-cursors of OAuth. That was a proprietary protocol, but one that has been used by hundreds of websites to provide add-on services to Google Account users by getting permission from users to access data in their Google Accounts. In fact, that was the key feature that a few of us used to start the Google Health portability effort back when it was only a prototype project with a few dedicated Googlers.

However, with the development of a common Internet standard in OAuth, we see much greater potential for data portability and secure mash-ups. Today we announced that the gadget platform now supports OAuth, and the interoperability of this standard was demonstrated by new iGoogle gadgets that AOL and MySpace both built to enable users to see their respective AOL or MySpace mailboxes (and other information) while on iGoogle. However, to ensure the user's privacy, this only works after the user has authorized AOL or MySpace to make their data available to the gadget running on iGoogle. We also previously announced that third-party developers can build their own iGoogle gadgets that access the OAuth-enabled APIs for Google applications such as Calendar, Picasa, and Docs. In fact, since both the gadget platform and OAuth technology are open standards, we are working to help other companies who run services similar to iGoogle to enhance them with support for these standards. Once that is in place, these new OAuth-powered gadgets that are available on iGoogle will also work on those other sites, including many of the gadgets that Google offers for its own applications. This provides a platform for some interesting mash-ups. For example, a third-party developer could create a single gadget that uses OAuth to access both Google OAuth-enabled APIs (such as a Gmail user's address book) and MySpace OAuth-enabled APIs (such as a user's friend list) and display a mashup of the combination.

While the combination of OAuth with gadgets is an exciting new use of the technology, most of the use of OAuth is between websites, such as to enable a user of Google Health to allow a clinical trial matching site to access his or her health profile. I previously mentioned that one privacy control provided by OAuth is that it defines a standard way for users to authorize one website to make their data accessible to another website. In addition, OAuth provides a way to do this without the first site needing to reveal the identity of the user -- it simply provides a different opaque security token to each additional website the user wants to share his or her data with. It would allow a mutual fund, for example, to provide an iGoogle gadget to their customers that would run on iGoogle and show the user the value of his or her mutual fund, but without giving Google any unique information about the user, such as a social security number or account number. In the future, maybe we will even see industries like banks use standards such as OAuth to allow their customers to authorize utility companies to perform direct debit from the user's bank account without that person having to actually share his or her bank account number with the utility vendor.

The OAuth community is continuing to enhance this standard and is very interested in having more companies engaged with its development. The OAuth.net website has more details about the current standard, and I maintain a website with advanced information about Google's use of OAuth, including work on integrating OAuth with desktop apps, and integrating with federation standards such as OpenID and SAML. If you're interested in engaging with the OAuth community, please get in touch with us.

Malware? We don't need no stinking malware!

Written by Oliver Fisher

"This site may harm your computer"
You may have seen those words in Google search results — but what do they mean? If you click the search result link you get another warning page instead of the website you were expecting. But if the web page was your grandmother's baking blog, you're still confused. Surely your grandmother hasn't been secretly honing her l33t computer hacking skills at night school. Google must have made a mistake and your grandmother's web page is just fine...



I work with the team that helps put the warning in Google's search results, so let me try to explain. The good news is that your grandmother is still kind and loves turtles. She isn't trying to start a botnet or steal credit card numbers. The bad news is that her website or the server that it runs on probably has a security vulnerability, most likely from some out-of-date software. That vulnerability has been exploited and malicious code has been added to your grandmother's website. It's most likely an invisible script or iframe that pulls content from another website that tries to attack any computer that views the page. If the attack succeeds, then viruses, spyware, key loggers, botnets, and other nasty stuff will get installed.

If you see the warning on a site in Google's search results, it's a good idea to pay attention to it. Google has automatic scanners that are constantly looking for these sorts of web pages. I help build the scanners and continue to be surprised by how accurate they are. There is almost certainly something wrong with the website even if it is run by someone you trust. The automatic scanners make unbiased decisions based on the malicious content of the pages, not the reputation of the webmaster.

Servers are just like your home computer and need constant updating. There are lots of tools that make building a website easy, but each one adds some risk of being exploited. Even if you're diligent and keep all your website components updated, your web host may not be. They control your website's server and may not have installed the most recent OS patches. And it's not just innocent grandmothers that this happens to. There have been warnings on the websites of banks, sports teams, and corporate and government websites.

Uh-oh... I need help!
Now that we understand what the malware label means in search results, what do you do if you're a webmaster and Google's scanners have found malware on your site?

There are some resources to help clean things up. The Google Webmaster Central blog has some tips and a quick security checklist for webmasters. Stopbadware.org has great information, and their forums have a number of helpful and knowledgeable volunteers who may be able to help (sometimes I'm one of them). You can also use the Google SafeBrowsing diagnostics page for your site (http://www.google.com/safebrowsing/diagnostic?site=<site-name-here>) to see specific information about what Google's automatic scanners have found. If your site has been flagged, Google's Webmaster Tools lists some of the URLs that were scanned and found to be infected.

Once you've cleaned up your website, use Google's Webmaster Tools to request a malware review. The automatic systems will rescan your website and the warning will be removed if the malware is gone.

Advance warning
I often hear webmasters asking Google for advance warning before a malware label is put on their website. When the label is applied, Google usually emails the website owners and then posts a warning in Google's Webmaster Tools. But no warning is given ahead of time - before the label is applied - so a webmaster can't quickly clean up the site before a warning is applied.

But, look at the situation from the user's point of view. As a user, I'd be pretty annoyed if Google sent me to a site it knew was dangerous. Even a short delay would expose some users to that risk, and it doesn't seem justified. I know it's frustrating for a webmaster to see a malware label on their website. But, ultimately, protecting users against malware makes the internet a safer place and everyone benefits, both webmasters and users.

Google's Webmaster Tools has started a test to provide warnings to webmasters that their server software may be vulnerable. Responding to that warning and updating server software can prevent your website from being compromised with malware. The best way to avoid a malware label is to never have any malware on the site!

Reviews
You can request a review via Google's Webmaster Tools and you can see the status of the review there. If you think the review is taking too long, make sure to check the status. Finding all the malware on a site is difficult and the automated scanners are far more accurate than humans. The scanners may have found something you've missed and the review may have failed. If your site has a malware label, Google's Webmaster Tools will also list some sample URLs that have problems. This is not a full list of all of the problem URLs (because that's often very, very long), but it should get you started.

Finally, don't confuse a malware review with a request for reconsideration. If Google's automated scanners find malware on your website, the site will usually not be removed from search results. There is also a different process that removes spammy websites from Google search results. If that's happened and you disagree with Google, you should submit a reconsideration request. But if your site has a malware label, a reconsideration request won't do any good — for malware you need to file a malware review from the Overview page.



How long will a review take?
Webmasters are eager to have a Google malware label removed from their site and often ask how long a review of the site will take. Both the original scanning and the review process are fully automated. The systems analyze large portions of the internet, which is big place, so the review may not happen immediately. Ideally, the label will be removed within a few hours. At its longest, the process should take a day or so.

New spam and virus trends from Enterprise

Written by Amanda Kleha, Google Apps Security & Compliance team


The Google Apps Security & Compliance team, which provides email and web security for more than 40,000 companies, regularly tracks trends in spam, viruses, and other threats. Check out some of our latest findings over on the Enterprise blog. Also, on Friday, August 15, at 10:00 am PT, we'll be hosting a webinar on keeping your business safe from web and email threats -- tune in if you'd like to learn more.

Keyczar: Safe and Simple Cryptography

Written by Steve Weis

Cryptography is notoriously hard to get right and if improperly used, can create serious security holes. Common mistakes include using the wrong cipher modes or obsolete algorithms, composing primitives in an unsafe manner, hard-coding keys in source code, or failing to anticipate the need for future key rotation. With these risks in mind, we're pleased to announce the open-source release of Keyczar.

Keyczar is a cryptographic toolkit that supports encryption and authentication for both symmetric and public-key algorithms. It addresses some of the aforementioned issues by choosing safe defaults, tagging outputs with key version information, and providing a simple application programming interface. Keyczar's key versioning system makes it easy to rotate and revoke keys, without worrying about backward compatibility or making any changes to source code.

We look forward to working with the open source community and continuing to make cryptography safer and easier to use. To download Keyczar or for more information, please visit our Google Code project and discussion group.

Are you using the latest web browser?

Written by Thomas Duebendorfer

In view of mass defacements of hundreds of thousand of web pages - with the intent to misuse them to launch drive-by download attacks - security researchers from ETH Zurich, Google, and IBM Internet Security Systems were interested in looking at the other side of the attack: the web browser. By analyzing the web browser versions seen in visits to Google websites, they have shown that more than 600 million Internet users don't use the latest version of their browser.

Slow migration to latest browser version
The researchers' paper, entitled "Understanding the Web Browser Threat", shows that as of June 2008, only 59.1% percent of Internet users worldwide use the latest major version of their preferred web browser. Firefox users are the most attentive: 92.2% of them surfed with Firefox 2, the latest major version before the recently released 3.0. Only 52.5% of Microsoft Internet Explorer users have updated to version 7, which is the most secure according to multiple publicly-cited Microsoft experts (among them Sandi Hardmeier). The study revealed that 637 million Internet users worldwide who use web browsers are either not running the latest version of their preferred browser or have not installed the latest patches. These users are vulnerable to exploitation due to their web browser's "built-in" vulnerabilities and the lack of more recent security mechanisms such as improved phishing protection.

Neglected security patches
Over the past 18 months, the study also shows, a maximum of 83.3% of Firefox users were using the latest major version of the web browser and also had all current patches installed (i.e. latest minor version). Only 56.1% and 47.6% of Opera and Internet Explorer users, respectively, were similarly utilizing fully-patched web browsers. Apple users are no better: since the public release of Safari 3, only 65.3% of users operate the latest Safari version.

Maximum measured share of users surfing the web with the most secure versions of Firefox, Safari, Opera and Internet Explorer in June 2008 as seen on Google websites.

Obsolete browser warning
The study's most important finding is that technical measures now in place do not sufficiently guarantee browser security, and that users' security awareness must be further developed. The problem is that most users are unaware that they are not using their browser's latest version. It must be made clear to web browser users that outdated software is associated with significantly higher risk. The researchers therefore suggest that, as a critical component of web software, a visible warning be instituted that warns the user of missing security patches in a way analogous to the 'best before' date in the perishable food industry. Software updates must also be made easier to find. The resulting transparency would go far in contributing to end user awareness of software weaknesses, and allow users to better evaluate risks.

Example "best before" implementation on a Web browser

As a side effect, having users migrate faster to the latest browser version would not only increase security but also make the lives of webmasters easier, as they would need to test and optimize websites for fewer older versions of web browsers.

Meet ratproxy, our passive web security assessment tool

Posted by Michal Zalewski

We're happy to announce that we've just open-sourced ratproxy, a passive web application security assessment tool that we've been using internally at Google. This utility, developed by our information security engineering team, is designed to transparently analyze legitimate, browser-driven interactions with a tested web property and automatically pinpoint, annotate, and prioritize potential flaws or areas of concern.

The proxy analyzes problems such as cross-site script inclusion threats, insufficient cross-site request forgery defenses, caching issues, cross-site scripting candidates, potentially unsafe cross-domain code inclusion schemes and information leakage scenarios, and much more. (A more-detailed discussion of these features and information on securing vulnerable applications is provided here.) Compared with more-traditional active crawlers, or with fully manual request inspection and modification frameworks, this approach offers several significant advantages in terms of minimized overhead; marginalized risk of site disruptions; high coverage of complex, client-driven application states in web 2.0 solutions; and insight into dynamic cross-domain trust models.

We decided to make this tool freely available as open source because we feel it will be a valuable contribution to the information security community, helping advance the community's understanding of security challenges associated with contemporary web technologies. We believe that responsible security research brings a net overall benefit to the safety of the Web as a whole, and have released this tool explicitly to support that kind of research.

To download the proxy, please visit this page. Also, please keep in mind that the proxy is designed solely to highlight interesting patterns in web applications, and a further analysis by a security professional is often required to interpret the results and their significance for the tested platform.