Google Security Blog

Syndikovat obsah
The latest news and insights from Google on security and safety on the Internet.
Aktualizace: 50 min 15 sek zpět

Additional protections by Safe Browsing for Android users

1 Prosinec, 2017 - 19:36
Posted by Paul Stanton, Safe Browsing Team

In our efforts to protect users and serve developers, the Google Safe Browsing team has expanded enforcement of Google's Unwanted Software Policy to further tamp down on unwanted and harmful mobile behaviors on Android. As part of this expanded enforcement, Google Safe Browsing will show warnings on apps and on websites leading to apps that collect a user’s personal data without their consent.

Apps handling personal user data (such as user phone number or email), or device data will be required to prompt users and to provide their own privacy policy in the app. Additionally, if an app collects and transmits personal data unrelated to the functionality of the app then, prior to collection and transmission, the app must prominently highlight how the user data will be used and have the user provide affirmative consent for such use.

These data collection requirements apply to all functions of the app. For example, during analytics and crash reportings, the list of installed packages unrelated to the app may not be transmitted from the device without prominent disclosure and affirmative consent.

These requirements apply to apps in Google Play and non-Play app markets. The Google Play team has also published guidelines for how Play apps should handle user data and provide disclosure.

Starting in 60 days, this expanded enforcement of Google’s Unwanted Software Policy may result in warnings shown on user devices via Google Play Protect or on webpages that lead to these apps. Webmasters whose sites show warnings due to distribution of these apps should refer to the Search Console for guidance on remediation and resolution of the warnings. Developers whose apps show warnings should refer to guidance in the Unwanted Software Help Center. Developers can also request an app review using this article on App verification and appeals, which contains guidance applicable to apps in both Google Play and non-Play app stores. Apps published in Google Play have specific criteria to meet Google Play’s enforcement of the Unwanted Software policy; these criteria are outlined in the Play August 2017 announcement.
Kategorie: Hacking & Security

Tizi: Detecting and blocking socially engineered spyware on Android

27 Listopad, 2017 - 23:48
Posted by Anthony Desnos, Megan Ruthven, and Richard Neal, Google Play Protect security engineers and Clement Lecigne, Threat Analysis Group

Google is constantly working to improve our systems that protect users from Potentially Harmful Applications (PHAs). Usually, PHA authors attempt to install their harmful apps on as many devices as possible. However, a few PHA authors spend substantial effort, time, and money to create and install their harmful app on a small number of devices to achieve a certain goal.

This blog post covers Tizi, a backdoor family with some rooting capabilities that was used in a targeted attack against devices in African countries, specifically: Kenya, Nigeria, and Tanzania. We'll talk about how the Google Play Protect and Threat Analysis teams worked together to detect and investigate Tizi-infected apps and remove and block them from Android devices.
What is Tizi?

Tizi is a fully featured backdoor that installs spyware to steal sensitive data from popular social media applications. The Google Play Protect security team discovered this family in September 2017 when device scans found an app with rooting capabilities that exploited old vulnerabilities. The team used this app to find more applications in the Tizi family, the oldest of which is from October 2015. The Tizi app developer also created a website and used social media to encourage more app installs from Google Play and third-party websites.

Here is an example social media post promoting a Tizi-infected app:

What is the scope of Tizi?

What are we doing?
To protect Android devices and users, we used Google Play Protect to disable Tizi-infected apps on affected devices and have notified users of all known affected devices. The developers' accounts have been suspended from Play.
The Google Play Protect team also used information and signals from the Tizi apps to update Google's on-device security services and the systems that search for PHAs. These enhancements have been enabled for all users of our security services and increases coverage for Google Play users and the rest of the Android ecosystem.
Additionally, there is more technical information below to help the security industry in our collective work against PHAs.

What do I need to do?
Through our investigation, we identified around 1,300 devices affected by Tizi. To reduce the chance of your device being affected by PHAs and other threats, we recommend these 5 basic steps:
  • Check permissions: Be cautious with apps that request unreasonable permissions. For example, a flashlight app shouldn't need access to send SMS messages.
  • Enable a secure lock screen: Pick a PIN, pattern, or password that is easy for you to remember and hard for others to guess.
  • Update your device: Keep your device up-to-date with the latest security patches. Tizi exploited older and publicly known security vulnerabilities, so devices that have up-to-date security patches are less exposed to this kind of attack.
  • Google Play Protect: Ensure Google Play Protect is enabled.
  • Locate your device: Practice finding your device, because you are far more likely to lose your device than install a PHA.

How does Tizi work?
The Google Play Protect team had previously classified some samples as spyware or backdoor PHAs without connecting them as a family. The early Tizi variants didn't have rooting capabilities or obfuscation, but later variants did.
After gaining root, Tizi steals sensitive data from popular social media apps like Facebook, Twitter, WhatsApp, Viber, Skype, LinkedIn, and Telegram. It usually first contacts its command-and-control servers by sending an SMS with the device's GPS coordinates to a specific number. Subsequent command-and-control communications are normally performed over regular HTTPS, though in some specific versions, Tizi uses the MQTT messaging protocol with a custom server. The backdoor contains various capabilities common to commercial spyware, such as recording calls from WhatsApp, Viber, and Skype; sending and receiving SMS messages; and accessing calendar events, call log, contacts, photos, Wi-Fi encryption keys, and a list of all installed apps. Tizi apps can also record ambient audio and take pictures without displaying the image on the device's screen.
Tizi can root the device by exploiting one of the following local vulnerabilities:
  • CVE-2012-4220
  • CVE-2013-2596
  • CVE-2013-2597
  • CVE-2013-2595
  • CVE-2013-2094
  • CVE-2013-6282
  • CVE-2014-3153
  • CVE-2015-3636
  • CVE-2015-1805
Most of these vulnerabilities target older chipsets, devices, and Android versions. All of the listed vulnerabilities are fixed on devices with a security patch level of April 2016 or later, and most of them were patched considerably prior to this date. Devices with this patch level or later are far less exposed to Tizi's capabilities. If a Tizi app is unable to take control of a device because the vulnerabilities it tries to use are are all patched, it will still attempt to perform some actions through the high level of permissions it asks the user to grant to it, mainly around reading and sending SMS messages and monitoring, redirecting, and preventing outgoing phone calls.

Samples uploaded to VirusTotal
To encourage further research in the security community, here are some sample applications embedding Tizi that were already on VirusTotal.
Package nameSHA256 digestSHA1 certificatecom.press.nasa.com.tanofresh4d780a6fc18458311250d4d1edc750468fdb9b3e4c950dce5b35d4567b47d4a7816bbee3cab5eed00b8bd16df56032a96e243201com.dailyworkout.tizi7c6af091a7b0f04fb5b212bd3c180ddcc6abf7cd77478fd22595e5b7aa7cfd9f404b4d1a7176e219eaa457b0050b4081c22a9a1acom.system.update.systemupdate7a956c754f003a219ea1d2205de3ef5bc354419985a487254b8aeb865442a55e4d2962ac1f6551435709a5a874595d855b1fa8ab

Additional digests linked to Tizi
To encourage further research in the security community, here are some sample digests of exploits and utilities that were used or abused by Tizi.
FilenameSHA256 digestrun_root_shellf2e45ea50fc71b62d9ea59990ced755636286121437ced6237aff90981388f6aiovyroot4d0887f41d0de2f31459c14e3133debcdf758ad8bbe57128d3bec2c907f2acf3filesbetyangu.tar9869871ed246d5670ebca02bb265a584f998f461db0283103ba58d4a650333be
Kategorie: Hacking & Security

Lock it up! New hardware protections for your lock screen with the Google Pixel 2

14 Listopad, 2017 - 20:15
Posted by Xiaowen Xin, Android Security Team
The new Google Pixel 2 ships with a dedicated hardware security module designed to be robust against physical attacks. This hardware module performs lockscreen passcode verification and protects your lock screen better than software alone.

To learn more about the new protections, let’s first review the role of the lock screen. Enabling a lock screen protects your data, not just against casual thieves, but also against sophisticated attacks. Many Android devices, including all Pixel phones, use your lockscreen passcode to derive the key that is then used to encrypt your data. Before you unlock your phone for the first time after a reboot, an attacker cannot recover the key (and hence your data) without knowing your passcode first. To protect against brute-force guessing your passcode, devices running Android 7.0+ verify your attempts in a secure environment that limits how often you can repeatedly guess. Only when the secure environment has successfully verified your passcode does it reveal a device and user-specific secret used to derive the disk encryption key.

Benefits of tamper-resistant hardware

The goal of these protections is to prevent attackers from decrypting your data without knowing your passcode, but the protections are only as strong as the secure environment that verifies the passcode. Performing these types of security-critical operations in tamper-resistant hardware significantly increases the difficulty of attacking it.
Tamper-resistant hardware comes in the form of a discrete chip separate from the System on a Chip (SoC). It includes its own flash, RAM, and other resources inside a single package, so it can fully control its own execution. It can also detect and defend against outside attempts to physically tamper with it.

In particular:
  • Because it has its own dedicated RAM, it’s robust against many side-channel information leakage attacks, such as those described in the TruSpy cache side-channel paper.
  • Because it has its own dedicated flash, it’s harder to interfere with its ability to store state persistently.
  • It loads its operating system and software directly from internal ROM and flash, and it controls all updates to it, so attackers can’t directly tamper with its software to inject malicious code.
  • Tamper-resistant hardware is resilient against many physical fault injection techniques including attempts to run outside normal operating conditions, such as wrong voltage, wrong clock speed, or wrong temperature. This is standardized in specifications such as the SmartCard IC Platform Protection Profile, and tamper-resistant hardware is often certified to these standards.
  • Tamper-resistant hardware is usually housed in a package that is resistant to physical penetration and designed to resist side channel attacks, including power analysis, timing analysis, and electromagnetic sniffing, such as described in the SoC it to EM paper.
Security module in Pixel 2
The new Google Pixel 2 ships with a security module built using tamper-resistant hardware that protects your lock screen and your data against many sophisticated hardware attacks.
In addition to all the benefits already mentioned, the security module in Pixel 2 also helps protect you against software-only attacks:
  • Because it performs very few functions, it has a super small attack surface.
  • With passcode verification happening in the security module, even in the event of a full compromise elsewhere, the attacker cannot derive your disk encryption key without compromising the security module first.
  • The security module is designed so that nobody, including Google, can update the passcode verification logic to a weakened version without knowing your passcode first.
Summary
Just like many other Google products, such as Chromebooks and Cloud, Android and Pixel are investing in additional hardware protections to make your device more secure. With the new Google Pixel 2, your data is safer against an entire class of sophisticated hardware attacks.
Kategorie: Hacking & Security