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Cross-posted on the Research Blog and the Chromium Blog

At Google, we are constantly trying to improve the techniques we use to protect our users' security and privacy. One such project, RAPPOR (Randomized Aggregatable Privacy-Preserving Ordinal Response), provides a new state-of-the-art, privacy-preserving way to learn software statistics that we can use to better safeguard our users’ security, find bugs, and improve the overall user experience.

Building on the concept of randomized response, RAPPOR enables learning statistics about the behavior of users’ software while guaranteeing client privacy. The guarantees of differential privacy, which are widely accepted as being the strongest form of privacy, have almost never been used in practice despite intense research in academia. RAPPOR introduces a practical method to achieve those guarantees.

To understand RAPPOR, consider the following example. Let’s say you wanted to count how many of your online friends were dogs, while respecting the maxim that, on the Internet, nobody should know you’re a dog. To do this, you could ask each friend to answer the question “Are you a dog?” in the following way. Each friend should flip a coin in secret, and answer the question truthfully if the coin came up heads; but, if the coin came up tails, that friend should always say “Yes” regardless. Then you could get a good estimate of the true count from the greater-than-half fraction of your friends that answered “Yes”. However, you still wouldn’t know which of your friends was a dog: each answer “Yes” would most likely be due to that friend’s coin flip coming up tails.

RAPPOR builds on the above concept, allowing software to send reports that are effectively indistinguishable from the results of random coin flips and are free of any unique identifiers. However, by aggregating the reports we can learn the common statistics that are shared by many users. We’re currently testing the use of RAPPOR in Chrome, to learn statistics about how unwanted software is hijacking users’ settings.

We believe that RAPPOR has the potential to be applied for a number of different purposes, so we're making it freely available for all to use. We'll continue development of RAPPOR as a standalone open-source project so that anybody can inspect test its reporting and analysis mechanisms, and help develop the technology. We’ve written up the technical details of RAPPOR in a report that will be published next week at the ACM Conference on Computer and Communications Security.

We’re encouraged by the feedback we’ve received so far from academics and other stakeholders, and we’re looking forward to additional comments from the community. We hope that everybody interested in preserving user privacy will review the technology and share their feedback at rappor-discuss@googlegroups.com.

Posted by Úlfar Erlingsson, Tech Lead Manager, Security Research

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2-Step Verification offers a strong extra layer of protection for Google Accounts. Once enabled, you’re asked for a verification code from your phone in addition to your password, to prove that it’s really you signing in from an unfamiliar device. Hackers usually work from afar, so this second factor makes it much harder for a hacker who has your password to access your account, since they don’t have your phone.

Today we’re adding even stronger protection for particularly security-sensitive individuals. Security Key is a physical USB second factor that only works after verifying the login site is truly a Google website, not a fake site pretending to be Google. Rather than typing a code, just insert Security Key into your computer’s USB port and tap it when prompted in Chrome. When you sign into your Google Account using Chrome and Security Key, you can be sure that the cryptographic signature cannot be phished.

Security Key and Chrome incorporate the open Universal 2nd Factor (U2F) protocol from the FIDO Alliance, so other websites with account login systems can get FIDO U2F working in Chrome today. It’s our hope that other browsers will add FIDO U2F support, too. As more sites and browsers come onboard, security-sensitive users can carry a single Security Key that works everywhere FIDO U2F is supported.

Security Key works with Google Accounts at no charge, but you’ll need to buy a compatible USB device directly from a U2F participating vendor. If you think Security Key may be right for you, we invite you to learn more.

Posted by Nishit Shah, Product Manager, Google Security

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Today we are publishing details of a vulnerability in the design of SSL version 3.0. This vulnerability allows the plaintext of secure connections to be calculated by a network attacker. I discovered this issue in collaboration with Thai Duong and Krzysztof Kotowicz (also Googlers).

SSL 3.0 is nearly 18 years old, but support for it remains widespread. Most importantly, nearly all browsers support it and, in order to work around bugs in HTTPS servers, browsers will retry failed connections with older protocol versions, including SSL 3.0. Because a network attacker can cause connection failures, they can trigger the use of SSL 3.0 and then exploit this issue.

Disabling SSL 3.0 support, or CBC-mode ciphers with SSL 3.0, is sufficient to mitigate this issue, but presents significant compatibility problems, even today. Therefore our recommended response is to support TLS_FALLBACK_SCSV. This is a mechanism that solves the problems caused by retrying failed connections and thus prevents attackers from inducing browsers to use SSL 3.0. It also prevents downgrades from TLS 1.2 to 1.1 or 1.0 and so may help prevent future attacks.

Google Chrome and our servers have supported TLS_FALLBACK_SCSV since February and thus we have good evidence that it can be used without compatibility problems. Additionally, Google Chrome will begin testing changes today that disable the fallback to SSL 3.0. This change will break some sites and those sites will need to be updated quickly.

In the coming months, we hope to remove support for SSL 3.0 completely from our client products.

Thank you to all the people who helped review and discuss responses to this issue.

Posted by Bodo Möller, Google Security Team

[Updated Oct 15 to note that SSL 3.0 is nearly 18 years old, not nearly 15 years old.]

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It’s been a year since we launched our Patch Reward program, a novel effort designed to recognize and reward proactive contributions to the security of key open-source projects that make the Internet tick. Our goal is to provide financial incentives for improvements that go beyond merely fixing a known security bug.

We started with a modest scope and reward amounts, but have gradually expanded the program over the past few months. We’ve seen some great work so far—and to help guide future submissions, we wanted to share some of our favorites:
  • Addition of Curve25519 and several other primitives in OpenSSH to strengthen its cryptographic foundations and improve performance.
  • A set of patches to reduce the likelihood of ASLR info leaks in Linux to make certain types of memory corruption bugs more difficult to exploit.
  • And, of course, the recent attack-surface-reducing function prefix patch in bash that helped mitigate a flurry of “Shellshock”-related bugs.

We hope that this list inspires even more contributions in the year to come. Of course, before participating, be sure to read the rules page. When done, simply send your nominations to security-patches@google.com. And keep up the great work!

Posted by Michal Zalewski, Google Security Team

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Security and privacy are top priorities for Google. We’ve invested a lot in making our products secure, including strong SSL encryption by default for Search, Gmail and Drive. We’re working to further extend encryption across all our services, ensuring that your connection to Google is private.

For some time, we’ve offered network administrators the ability to require the use of SafeSearch by their users, which filters out explicit content from search results; this is especially important for schools. However, using this functionality has meant that searches were sent over an unencrypted connection to Google. Unfortunately, this has been the target of abuse by other groups looking to snoop on people’s searches, so we will be removing it as of early December.

Going forward, organizations can require SafeSearch on their networks while at the same time ensuring that their users’ connections to Google remain encrypted. (This is in addition to existing functionality that allows SafeSearch to be set on individual browsers and to be enabled by policy on managed devices like Chromebooks.) Network administrators can read more about how to enable this new feature here.

Posted by Brian Fitzpatrick, Engineering Director

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Cross-posted on the Chromium Blog

We work hard to keep you safe online. In Chrome, for instance, we warn users against malware and phishing and offer rewards for finding security bugs. Due in part to our collaboration with the research community, we’ve squashed more than 700 Chrome security bugs and have rewarded more than $1.25 million through our bug reward program. But as Chrome has become more secure, it’s gotten even harder to find and exploit security bugs.

This is a good problem to have! In recognition of the extra effort it takes to uncover vulnerabilities in Chrome, we’re increasing our reward levels. We’re also making some changes to be more transparent with researchers reporting a bug.

First, we’re increasing our usual reward pricing range to $500-$15,000 per bug, up from a previous published maximum of $5,000. This is accompanied with a clear breakdown of likely reward amounts by bug type. As always, we reserve the right to reward above these levels for particularly great reports. (For example, last month we awarded $30,000 for a very impressive report.)

Second, we’ll pay at the higher end of the range when researchers can provide an exploit to demonstrate a specific attack path against our users. Researchers now have an option to submit the vulnerability first and follow up with an exploit later. We believe that this a win-win situation for security and researchers: we get to patch bugs earlier and our contributors get to lay claim to the bugs sooner, lowering the chances of submitting a duplicate report.

Third, Chrome reward recipients will be listed in the Google Hall of Fame, so you’ve got something to print out and hang on the fridge.

As a special treat, we’re going to back-pay valid submissions from July 1, 2014 at the increased reward levels we’re announcing today. Good times.

We’ve also answered some new FAQs on our rules page, including questions about our new Trusted Researcher program and a bit about our philosophy and alternative markets for zero-day bugs.

Happy bug hunting!

Posted by Tim Willis, Hacker Philanthropist, Chrome Security Team

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Cross-posted on the Open Source Blog

A recent Pew study found that 86% of people surveyed had taken steps to protect their security online. This is great—more security is always good. However, if people are indeed working to protect themselves, why are we still seeing incidents, breaches, and confusion? In many cases these problems recur because the technology that allows people to secure their communications, content and online activity is too hard to use. 

In other words, the tools for the job exist. But while many of these tools work technically, they don’t always work in ways that users expect. They introduce extra steps or are simply confusing and cumbersome. (“Is this a software bug, or am I doing something wrong?”) However elegant and intelligent the underlying technology (and much of it is truly miraculous), the results are in: if people can’t use it easily, many of them won’t. 

We believe that people shouldn’t have to make a trade-off between security and ease of use. This is why we’re happy to support Simply Secure, a new organization dedicated to improving the usability and safety of open-source tools that help people secure their online lives. 

Over the coming months, Simply Secure will be collaborating with open-source developers, designers, researchers, and others to take what’s there—groundbreaking work from efforts like Open Whisper Systems, The Guardian Project, Off-the-Record Messaging, and more—and work to make them easier to understand and use. 

We’re excited for a future where people won’t have to choose between ease and security, and where tools that allow people to secure their communications, content, and online activity are as easy as choosing to use them.

Posted by Meredith Whittaker, Open Source Research Lead and Ben Laurie, Senior Staff Security Engineer

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One of the unfortunate realities of the Internet today is a phenomenon known in security circles as “credential dumps”—the posting of lists of usernames and passwords on the web. We’re always monitoring for these dumps so we can respond quickly to protect our users. This week, we identified several lists claiming to contain Google and other Internet providers’ credentials.

We found that less than 2% of the username and password combinations might have worked, and our automated anti-hijacking systems would have blocked many of those login attempts. We’ve protected the affected accounts and have required those users to reset their passwords.

It’s important to note that in this case and in others, the leaked usernames and passwords were not the result of a breach of Google systems. Often, these credentials are obtained through a combination of other sources. 

For instance, if you reuse the same username and password across websites, and one of those websites gets hacked, your credentials could be used to log into the others. Or attackers can use malware or phishing schemes to capture login credentials.

We’re constantly working to keep your accounts secure from phishing, malware and spam. For instance, if we see unusual account activity, we’ll stop sign-in attempts from unfamiliar locations and devices. You can review this activity and confirm whether or not you actually took the action.

A few final tips: Make sure you’re using a strong password unique to Google. Update your recovery options so we can reach you by phone or email if you get locked out of your account. And consider 2-step verification, which adds an extra layer of security to your account. You can visit g.co/accountcheckup where you’ll see a list of many of the security controls at your disposal.

Posted by Borbala Benko, Elie Bursztein, Tadek Pietraszek and Mark Risher, Google Spam & Abuse Team

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Cross-posted on the Chromium Blog

The SHA-1 cryptographic hash algorithm has been known to be considerably weaker than it was designed to be since at least 2005 — 9 years ago. Collision attacks against SHA-1 are too affordable for us to consider it safe for the public web PKI. We can only expect that attacks will get cheaper.

That’s why Chrome will start the process of sunsetting SHA-1 (as used in certificate signatures for HTTPS) with Chrome 39 in November. HTTPS sites whose certificate chains use SHA-1 and are valid past 1 January 2017 will no longer appear to be fully trustworthy in Chrome’s user interface.

SHA-1's use on the Internet has been deprecated since 2011, when the CA/Browser Forum, an industry group of leading web browsers and certificate authorities (CAs) working together to establish basic security requirements for SSL certificates, published their Baseline Requirements for SSL. These Requirements recommended that all CAs transition away from SHA-1 as soon as possible, and followed similar events in other industries and sectors, such as NIST deprecating SHA-1 for government use in 2010.

We have seen this type of weakness turn into a practical attack before, with the MD5 hash algorithm. We need to ensure that by the time an attack against SHA-1 is demonstrated publicly, the web has already moved away from it. Unfortunately, this can be quite challenging. For example, when Chrome disabled MD5, a number of enterprises, schools, and small businesses were affected when their proxy software — from leading vendors — continued to use the insecure algorithms, and were left scrambling for updates. Users who used personal firewall software were also affected.

We plan to surface, in the HTTPS security indicator in Chrome, the fact that SHA-1 does not meet its design guarantee. We are taking a measured approach, gradually ratcheting down the security indicator and gradually moving the timetable up (keep in mind that we release stable versions of Chrome about 6-8 weeks after their branch point):

Chrome 39 (Branch point 26 September 2014)
Sites with end-entity (“leaf”) certificates that expire on or after 1 January 2017, and which include a SHA-1-based signature as part of the certificate chain, will be treated as “secure, but with minor errors”.

The current visual display for “secure, but with minor errors” is a lock with a yellow triangle, and is used to highlight other deprecated and insecure practices, such as passive mixed content.

Chrome 40 (Branch point 7 November 2014; Stable after holiday season)
Sites with end-entity certificates that expire between 1 June 2016 to 31 December 2016 (inclusive), and which include a SHA-1-based signature as part of the certificate chain, will be treated as “secure, but with minor errors”. 

Sites with end-entity certificates that expire on or after 1 January 2017, and which include a SHA-1-based signature as part of the certificate chain, will be treated as “neutral, lacking security”.

The current visual display for “neutral, lacking security” is a blank page icon, and is used in other situations, such as HTTP.
Chrome 41 (Branch point in Q1 2015)
Sites with end-entity certificates that expire between 1 January 2016 and 31 December 2016 (inclusive), and which include a SHA-1-based signature as part of the certificate chain, will be treated as “secure, but with minor errors”. 

Sites with end-entity certificates that expire on or after 1 January 2017, and which include a SHA-1-based signature as part of the certificate chain, will be treated as “affirmatively insecure”. Subresources from such domain will be treated as “active mixed content”.

The current visual display for “affirmatively insecure” is a lock with a red X, and a red strike-through text treatment in the URL scheme.
Note: SHA-1-based signatures for trusted root certificates are not a problem because TLS clients trust them by their identity, rather than by the signature of their hash.

Posted by Chris Palmer, Secure Socket Lover and Ryan Sleevi, Transport Layer Securer

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Cross-posted on the Chrome Blog

You should be able to use the web safely, without fear that malware could take control of your computer, or that you could be tricked into giving up personal information in a phishing scam.

That’s why we’ve invested so much in tools that protect you online. Our Safe Browsing service protects you from malicious websites and warns you about malicious downloads in Chrome. We’re currently showing more than three million download warnings per week—and because we make this technology available for other browsers to use, we can help keep 1.1 billion people safe.

Starting next week, we’ll be expanding Safe Browsing protection against additional kinds of deceptive software: programs disguised as a helpful download that actually make unexpected changes to your computer—for instance, switching your homepage or other browser settings to ones you don’t want.

We’ll show a warning in Chrome whenever an attempt is made to trick you into downloading and installing such software. (If you still wish to proceed despite the warning, you can access it from your Downloads list.)
As always, be careful and make sure you trust the source when downloading software. Check out these tips to learn how you can stay safe on the web.

Posted by Moheeb Abu Rajab, Staff Engineer, Google Security