Posted by Royal Hansen, Vice President, Security

Black History Month may be coming to a close, but our work to build sustainable equity for Google’s Black+ community, and externally is ongoing. Currently, Black Americans make up less than 12% of information security analysts in the U.S. In an industry that consistently requires new ideas to spark positive change and stand out against the status quo, it is necessary to have individuals who think, speak, and act in diverse ways. Diverse security teams are more innovative, produce better products and enhance an organization’s ability to defend against cyber threats.

In an effort to amplify the contributions of the Black+ community to security and privacy fields, we’ll be sharing profiles of Black+ Googlers working on innovative privacy and security solutions over the coming weeks, starting with Camllie Stewart, Google’s Head of Security Policy for Google Play and Android.

Camille co-founded #ShareTheMicInCyber, an initiative that pairs Black security practitioners with prominent allies, lending their social media platforms to the practitioners for the day. The goal is to break down barriers, engage the security community, and promote sustained action. The #ShareTheMicInCyber campaign will highlight Black women in the security and privacy sector on LinkedIn and Twitter on March 19, 2021 and throughout March 2021 in celebration of Women’s History Month. Follow the #ShareTheMicInCyber on March 19th to support and amplify Black women in security and privacy.

Read more about Camille’s story below 

#ShareTheMicInCyber: Camille Stewart

Today, we will hear from Camille Stewart, she leads security, privacy, election integrity, and dis/misinformation policy efforts for Google’s mobile business. She also spearheads a cross-Google security initiative that sets the strategic vision and objectives for Google’s engagement on security and privacy issues.

In her (not so) spare time, Camille is co-founder of the #ShareTheMicInCyber initiative – which aims to elevate the profiles, work, and lived experiences of Black cyber practitioners. This initiative has garnered national and international attention and has been a force for educating and bringing awareness to the challenges Black security practitioners face in industry. Camille is also a cybersecurity fellow at Harvard University, New America and Truman National Security Project. She sits on the board of the International Foundation for Electoral Systems and of Girl Security, an organization that is working to close the gender gap in national security through learning, training, and mentoring support for girls.

Why do you work in security or privacy?

I work in this space to empower people in and through technology by translating and solving the complex challenges that lie at the intersection of technology, security, society, and the law.

Tell us a little bit about your career journey to Google

Before life at Google, I managed cybersecurity, election security, tech innovation, and risk issues at Deloitte. Prior to that, I was appointed by President Barack Obama to be the Senior Policy Advisor for Cyber Infrastructure & Resilience Policy at the Department of Homeland Security. I was the Senior Manager of Legal Affairs at Cyveillance, a cybersecurity company after working on Capitol Hill.

What is your security or privacy “soapbox”?

Right now, I have a few. Users being intentional about their digital security similar to their physical security especially with their mobile devices and apps. As creators of technology, we need to be more intentional about how we educate our users on safety and security. At Google, security is core to everything we do and build, it has to be. We recently launched our Safer With Google campaign which I believe is a great resource for helping users better understand their security and privacy journey.

As an industry, we need to make meaningful national and international progress on digital supply chain transparency and security.

Lastly, the fact that systemic racism is a cybersecurity threat. I recently penned a piece for the Council on Foreign Relations that explores how racism influences cybersecurity and what we must do as an industry to address it.

If you are interested in following Camille’s work here at Google and beyond, please follow her on Twitter @CamilleEsq. We will be bringing you more profiles over the coming weeks and we hope you will engage with and share these with your network. 

If you are interested in participating or learning more about #ShareTheMicInCyber, click here.

Memory-safety vulnerabilities have dominated the security field for years and often lead to issues that can be exploited to take over entire systems. 

A recent study found that “~70% of the vulnerabilities addressed through a security update each year continue to be memory safety issues.” Another analysis on security issues in the ubiquitous `curl` command line tool showed that 53 out of 95 bugs would have been completely prevented by using a memory-safe language.


Software written in unsafe languages often contains hard-to-catch bugs that can result in severe security vulnerabilities, and we take these issues seriously at Google. That’s why we’re expanding our collaboration with the Internet Security Research Group to support the reimplementation of critical open-source software in memory-safe languages. We previously worked with the ISRG to help secure the Internet by making TLS certificates available to everyone for free, and we’re looking forward to continuing to work together on this new initiative.

It’s time to start taking advantage of memory-safe programming languages that prevent these errors from being introduced. At Google, we understand the value of the open source community and in giving back to support a strong ecosystem. 

To date, our free OSS-Fuzz service has found over 5,500 vulnerabilities across 375 open source projects caused by memory safety errors, and our Rewards Program helps encourage adoption of fuzzing through financial incentives. We’ve also released other projects like Syzkaller to detect bugs in operating system kernels, and sandboxes like gVisor to reduce the impact of bugs when they are found.

The ISRG’s approach of working directly with maintainers to support rewriting tools and libraries incrementally falls directly in line with our perspective here at Google. 

The new Rust-based HTTP and TLS backends for curl and now this new TLS library for Apache httpd are an important starting point in this overall effort. These codebases sit at the gateway to the internet and their security is critical in the protection of data for millions of users worldwide. 

We’d like to thank the maintainers of these projects for working on such widely-used and important infrastructure, and for participating in this effort.

We’re happy to be able to support these communities and the ISRG to make the Internet a safer place. We appreciate their leadership in this area and we look forward to expanding this program in 2021.


Open source security is a collaborative effort. If you’re interested in learning more about our efforts, please join us in the Securing Critical Projects Working Group of the Open Source Security Foundation.


[Cross-posted from the Android Developers Blog]

As phones become faster and smarter, they play increasingly important roles in our lives, functioning as our extended memory, our connection to the world at large, and often the primary interface for communication with friends, family, and wider communities. It is only natural that as part of this evolution, we’ve come to entrust our phones with our most private information, and in many ways treat them as extensions of our digital and physical identities.

This trust is paramount to the Android Security team. The team focuses on ensuring that Android devices respect the privacy and sensitivity of user data. A fundamental aspect of this work centers around the lockscreen, which acts as the proverbial front door to our devices. After all, the lockscreen ensures that only the intended user(s) of a device can access their private data.

This blog post outlines recent improvements around how users interact with the lockscreen on Android devices and more generally with authentication. In particular, we focus on two categories of authentication that present both immense potential as well as potentially immense risk if not designed well: biometrics and environmental modalities.

The tiered authentication model

Before getting into the details of lockscreen and authentication improvements, we first want to establish some context to help relate these improvements to each other. A good way to envision these changes is to fit them into the framework of the tiered authentication model, a conceptual classification of all the different authentication modalities on Android, how they relate to each other, and how they are constrained based on this classification.

The model itself is fairly simple, classifying authentication modalities into three buckets of decreasing levels of security and commensurately increasing constraints. The primary tier is the least constrained in the sense that users only need to re-enter a primary modality under certain situations (for example, after each boot or every 72 hours) in order to use its capability. The secondary and tertiary tiers are more constrained because they cannot be set up and used without having a primary modality enrolled first and they have more constraints further restricting their capabilities.

  1. Primary Tier – Knowledge Factor: The first tier consists of modalities that rely on knowledge factors, or something the user knows, for example, a PIN, pattern, or password. Good high-entropy knowledge factors, such as complex passwords that are hard to guess, offer the highest potential guarantee of identity.

    Knowledge factors are especially useful on Android becauses devices offer hardware backed brute-force protection with exponential-backoff, meaning Android devices prevent attackers from repeatedly guessing a PIN, pattern, or password by having hardware backed timeouts after every 5 incorrect attempts. Knowledge factors also confer additional benefits to all users that use them, such as File Based Encryption (FBE) and encrypted device backup.

  1. Secondary Tier – Biometrics: The second tier consists primarily of biometrics, or something the user is. Face or fingerprint based authentications are examples of secondary authentication modalities. Biometrics offer a more convenient but potentially less secure way of confirming your identity with a device.

We will delve into Android biometrics in the next section.

  1. The Tertiary Tier – Environmental: The last tier includes modalities that rely on something the user has. This could either be a physical token, such as with Smart Lock’s Trusted Devices where a phone can be unlocked when paired with a safelisted bluetooth device. Or it could be something inherent to the physical environment around the device, such as with Smart Lock’s Trusted Places where a phone can be unlocked when it is taken to a safelisted location.

    Improvements to tertiary authentication

    While both Trusted Places and Trusted Devices (and tertiary modalities in general) offer convenient ways to get access to the contents of your device, the fundamental issue they share is that they are ultimately a poor proxy for user identity. For example, an attacker could unlock a misplaced phone that uses Trusted Place simply by driving it past the user’s home, or with moderate amount of effort, spoofing a GPS signal using off-the-shelf Software Defined Radios and some mild scripting. Similarly with Trusted Device, access to a safelisted bluetooth device also gives access to all data on the user’s phone.

    Because of this, a major improvement has been made to the environmental tier in Android 10. The Tertiary tier was switched from an active unlock mechanism into an extending unlock mechanism instead. In this new mode, a tertiary tier modality can no longer unlock a locked device. Instead, if the device is first unlocked using either a primary or secondary modality, it can continue to keep it in the unlocked state for a maximum of four hours.

A closer look at Android biometrics

Biometric implementations come with a wide variety of security characteristics, so we rely on the following two key factors to determine the security of a particular implementation:

  1. Architectural security: The resilience of a biometric pipeline against kernel or platform compromise. A pipeline is considered secure if kernel and platform compromises don’t grant the ability to either read raw biometric data, or inject synthetic data into the pipeline to influence an authentication decision.
  2. Spoofability: Is measured using the Spoof Acceptance Rate (SAR). SAR is a metric first introduced in Android P, and is intended to measure how resilient a biometric is against a dedicated attacker. Read more about SAR and its measurement in Measuring Biometric Unlock Security.

We use these two factors to classify biometrics into one of three different classes in decreasing order of security:

  • Class 3 (formerly Strong)
  • Class 2 (formerly Weak)
  • Class 1 (formerly Convenience)

Each class comes with an associated set of constraints that aim to balance their ease of use with the level of security they offer.

These constraints reflect the length of time before a biometric falls back to primary authentication, and the allowed application integration. For example, a Class 3 biometric enjoys the longest timeouts and offers all integration options for apps, while a Class 1 biometric has the shortest timeouts and no options for app integration. You can see a summary of the details in the table below, or the full details in the Android Android Compatibility Definition Document (CDD).

1 App integration means exposing an API to apps (e.g., via integration with BiometricPrompt/BiometricManager, androidx.biometric, or FIDO2 APIs)

2 Keystore integration means integrating Keystore, e.g., to release app auth-bound keys

Benefits and caveats

Biometrics provide convenience to users while maintaining a high level of security. Because users need to set up a primary authentication modality in order to use biometrics, it helps boost the lockscreen adoption (we see an average of 20% higher lockscreen adoption on devices that offer biometrics versus those that do not). This allows more users to benefit from the security features that the lockscreen provides: gates unauthorized access to sensitive user data and also confers other advantages of a primary authentication modality to these users, such as encrypted backups. Finally, biometrics also help reduce shoulder surfing attacks in which an attacker tries to reproduce a PIN, pattern, or password after observing a user entering the credential.

However, it is important that users understand the trade-offs involved with the use of biometrics. Primary among these is that no biometric system is foolproof. This is true not just on Android, but across all operating systems, form-factors, and technologies. For example, a face biometric implementation might be fooled by family members who resemble the user or a 3D mask of the user. A fingerprint biometric implementation could potentially be bypassed by a spoof made from latent fingerprints of the user. Although anti-spoofing or Presentation Attack Detection (PAD) technologies have been actively developed to mitigate such spoofing attacks, they are mitigations, not preventions.

One effort that Android has made to mitigate the potential risk of using biometrics is the lockdown mode introduced in Android P. Android users can use this feature to temporarily disable biometrics, together with Smart Lock (for example, Trusted Places and Trusted Devices) as well as notifications on the lock screen, when they feel the need to do so.

To use the lockdown mode, users first need to set up a primary authentication modality and then enable it in settings. The exact setting where the lockdown mode can be enabled varies by device models, and on a Google Pixel 4 device it is under Settings > Display > Lock screen > Show lockdown option. Once enabled, users can trigger the lockdown mode by holding the power button and then clicking the Lockdown icon on the power menu. A device in lockdown mode will return to the non-lockdown state after a primary authentication modality (such as a PIN, pattern, or password) is used to unlock the device.

BiometricPrompt – New APIs

In order for developers to benefit from the security guarantee provided by Android biometrics and to easily integrate biometric authentication into their apps to better protect sensitive user data, we introduced the BiometricPrompt APIs in Android P.

There are several benefits of using the BiometricPrompt APIs. Most importantly, these APIs allow app developers to target biometrics in a modality-agnostic way across different Android devices (that is, BiometricPrompt can be used as a single integration point for various biometric modalities supported on devices), while controlling the security guarantees that the authentication needs to provide (such as requiring Class 3 or Class 2 biometrics, with device credential as a fallback). In this way, it helps protect app data with a second layer of defenses (in addition to the lockscreen) and in turn respects the sensitivity of user data. Furthermore, BiometricPrompt provides a persistent UI with customization options for certain information (for example, title and description), offering a consistent user experience across biometric modalities and across Android devices.

As shown in the following architecture diagram, apps can integrate with biometrics on Android devices through either the framework API or the support library (that is, androidx.biometric for backward compatibility). One thing to note is that FingerprintManager is deprecated because developers are encouraged to migrate to BiometricPrompt for modality-agnostic authentications.

Improvements to BiometricPrompt

Android 10 introduced the BiometricManager class that developers can use to query the availability of biometric authentication and included fingerprint and face authentication integration for BiometricPrompt.

In Android 11, we introduce new features such as the BiometricManager.Authenticators interface which allows developers to specify the authentication types accepted by their apps, as well as additional support for auth-per-use keys within the BiometricPrompt class.

More details can be found in the Android 11 preview and Android Biometrics documentation. Read more about BiometricPrompt API usage in our blog post Using BiometricPrompt with CryptoObject: How and Why and our codelab Login with Biometrics on Android.

It has been two years since we officially expanded the scope of Google’s Vulnerability Reward Program (VRP) to include the identification of product abuse risks.
Thanks to your work, we have identified more than 750 previously unknown product abuse risks, preventing abuse in Google products and protecting our users. Collaboration to address abuse is important, and we are committed to supporting research on this growing challenge. To take it one step further, and as of today, we are announcing increased reward amounts for reports focusing on potential attacks in the product abuse space.
The nature of product abuse is constantly changing. Why? The technology (product and protection) is changing, the actors are changing, and the field is growing. Within this dynamic environment, we are particularly interested in research that protects users’ privacy, ensures the integrity of our technologies, as well as prevents financial fraud or other harms at scale.
Research in the product abuse space helps us deliver trusted and safe experiences to our users. Martin Vigo’s research on Google Meet’s dial-in feature is one great example of an 31337 report that allowed us to better protect users against bad actors. His research provided insight on how an attacker could attempt to find Meet Phone Numbers/Pin, which enabled us to launch further protections to ensure that Meet would provide a secure technology connecting us while we’re apart.
New Reward Amounts for Abuse Risks
What’s new? Based on the great submissions that we received in the past as well as feedback from our Bug Hunters, we increased the highest reward by 166% from $5,000 to $13,337. Research with medium to high impact and probability will now be eligible for payment up to $5,000.
What did not change? Identification of new product abuse risks remains the primary goal of the program. Reports that qualify for a reward are those that will result in changes to the product code, as opposed to removal of individual pieces of abusive content. The final reward amount for a given abuse risk report also remains  at the discretion of the reward panel. When evaluating the impact of an abuse risk, the panels look at both the severity of the issue as well as the number of impacted users.
What’s next? We plan to expand the scope of Vulnerability Research Grants to support research preventing abuse risks. Stay tuned for more information!
Starting today the new rewards take effect. Any reports that were submitted before September 1, 2020 will be rewarded based on the previous rewards table.
We look forward to working closely together with the researcher community to prevent abuse of Google products and ensure user safety.
Happy bug hunting!

Trust is very important when it comes to the relationship between a user and their smartphone. While phone functionality and design can enhance the user experience, security is fundamental and foundational to our relationship with our phones.There are multiple ways to build trust around the security capabilities that a device provides and we continue to invest in verifiable ways to do just that.

Pixel 4a ioXt certification

Today we are happy to announce that the Pixel 4/4 XL and the newly launched Pixel 4a are the first Android smartphones to go through ioXt certification against the Android Profile.

The Internet of Secure Things Alliance (ioXt) manages a security compliance assessment program for connected devices. ioXt has over 200 members across various industries, including Google, Amazon, Facebook, T-Mobile, Comcast, Zigbee Alliance, Z-Wave Alliance, Legrand, Resideo, Schneider Electric, and many others. With so many companies involved, ioXt covers a wide range of device types, including smart lighting, smart speakers, webcams, and Android smartphones.

The core focus of ioXt is “to set security standards that bring security, upgradability and transparency to the market and directly into the hands of consumers.” This is accomplished by assessing devices against a baseline set of requirements and relying on publicly available evidence. The goal of ioXt’s approach is to enable users, enterprises, regulators, and other stakeholders to understand the security in connected products to drive better awareness towards how these products are protecting the security and privacy of users.

ioXt’s baseline security requirements are tailored for product classes, and the ioXt Android Profile enables smartphone manufacturers to differentiate security capabilities, including biometric authentication strength, security update frequency, length of security support lifetime commitment, vulnerability disclosure program quality, and preloaded app risk minimization.

We believe that using a widely known industry consortium standard for Pixel certification provides increased trust in the security claims we make to our users. NCC Group has published an audit report that can be downloaded here. The report documents the evaluation of Pixel 4/4 XL and Pixel 4a against the ioXt Android Profile.

Security by Default is one of the most important criteria used in the ioXt Android profile. Security by Default rates devices by cumulatively scoring the risk for all preloads on a particular device. For this particular measurement, we worked with a team of university experts from the University of Cambridge, University of Strathclyde, and Johannes Kepler University in Linz to create a formula that considers the risk of platform signed apps, pregranted permissions on preloaded apps, and apps communicating using cleartext traffic.

Screenshot of the presentation of the Android Device Security Database at the Android Security Symposium 2020

In partnership with those teams, Google created Uraniborg, an open source tool that collects necessary attributes from the device and runs it through this formula to come up with a raw score. NCC Group leveraged Uraniborg to conduct the assessment for the ioXt Security by Default category.

As part of our ongoing certification efforts, we look forward to submitting future Pixel smartphones through the ioXt standard, and we encourage the Android device ecosystem to participate in similar transparency efforts for their devices.

Acknowledgements: This post leveraged contributions from Sudhi Herle, Billy Lau and Sam Schumacher


Today we’re announcing that Chrome will gradually ensure that secure (HTTPS) pages only download secure files. In a series of steps outlined below, we’ll start blocking “mixed content downloads” (non-HTTPS downloads started on secure pages). This move follows a plan we announced last year to start blocking all insecure subresources on secure pages.
Insecurely-downloaded files are a risk to users’ security and privacy. For instance, insecurely-downloaded programs can be swapped out for malware by attackers, and eavesdroppers can read users’ insecurely-downloaded bank statements. To address these risks, we plan to eventually remove support for insecure downloads in Chrome.
As a first step, we are focusing on insecure downloads started on secure pages. These cases are especially concerning because Chrome currently gives no indication to the user that their privacy and security are at risk.
Starting in Chrome 82 (to be released April 2020), Chrome will gradually start warning on, and later blocking, these mixed content downloads. File types that pose the most risk to users (e.g., executables) will be impacted first, with subsequent releases covering more file types. This gradual rollout is designed to mitigate the worst risks quickly, provide developers an opportunity to update sites, and minimize how many warnings Chrome users have to see.
We plan to roll out restrictions on mixed content downloads on desktop platforms (Windows, macOS, Chrome OS and Linux) first. Our plan for desktop platforms is as follows:

  • In Chrome 81 (released March 2020) and later:
    • Chrome will print a console message warning about all mixed content downloads.
  • In Chrome 82 (released April 2020):
    • Chrome will warn on mixed content downloads of executables (e.g. .exe).
  • In Chrome 83 (released June 2020):
    • Chrome will block mixed content executables
    • Chrome will warn on mixed content archives (.zip) and disk images (.iso).
  • In Chrome 84 (released August 2020):
    • Chrome will block mixed content executables, archives and disk images
    • Chrome will warn on all other mixed content downloads except image, audio, video and text formats.
  • In Chrome 85 (released September 2020):
    • Chrome will warn on mixed content downloads of images, audio, video, and text
    • Chrome will block all other mixed content downloads
  • In Chrome 86 (released October 2020) and beyond, Chrome will block all mixed content downloads.
Example of a potential warning
Chrome will delay the rollout for Android and iOS users by one release, starting warnings in Chrome 83. Mobile platforms have better native protection against malicious files, and this delay will give developers a head-start towards updating their sites before impacting mobile users.
Developers can prevent users from ever seeing a download warning by ensuring that downloads only use HTTPS. In the current version of Chrome Canary, or in Chrome 81 once released, developers can activate a warning on all mixed content downloads for testing by enabling the “Treat risky downloads over insecure connections as active mixed content” flag at chrome://flags/#treat-unsafe-downloads-as-active-content.
Enterprise and education customers can disable blocking on a per-site basis via the existing InsecureContentAllowedForUrls policy by adding a pattern matching the page requesting the download.
In the future, we expect to further restrict insecure downloads in Chrome. We encourage developers to fully migrate to HTTPS to avoid future restrictions and fully protect their users. Developers with questions are welcome to email us at security-dev@chromium.org.