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 name
SHA256 digest
SHA1 certificate
com.press.nasa.com.tanofresh
4d780a6fc18458311250d4d1edc750468fdb9b3e4c950dce5b35d4567b47d4a7
816bbee3cab5eed00b8bd16df56032a96e243201
com.dailyworkout.tizi
7c6af091a7b0f04fb5b212bd3c180ddcc6abf7cd77478fd22595e5b7aa7cfd9f
404b4d1a7176e219eaa457b0050b4081c22a9a1a
com.system.update.systemupdate
7a956c754f003a219ea1d2205de3ef5bc354419985a487254b8aeb865442a55e
4d2962ac1f6551435709a5a874595d855b1fa8ab


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.

Filename
SHA256 digest
run_root_shell
f2e45ea50fc71b62d9ea59990ced755636286121437ced6237aff90981388f6a
iovyroot
4d0887f41d0de2f31459c14e3133debcdf758ad8bbe57128d3bec2c907f2acf3
filesbetyangu.tar
9869871ed246d5670ebca02bb265a584f998f461db0283103ba58d4a650333be
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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.


How hijackers steal passwords on the black market

Our research tracked several black markets that traded third-party password breaches, as well as 25,000 blackhat tools used for phishing and keylogging. In total, these sources helped us identify 788,000 credentials stolen via keyloggers, 12 million credentials stolen via phishing, and 3.3 billion credentials exposed by third-party breaches.

While our study focused on Google, these password stealing tactics pose a risk to all account-based online services. In the case of third-party data breaches, 12% of the exposed records included a Gmail address serving as a username and a password; of those passwords, 7% were valid due to reuse. When it comes to phishing and keyloggers, attackers frequently target Google accounts to varying success: 12-25% of attacks yield a valid password.

However, because a password alone is rarely sufficient for gaining access to a Google account, increasingly sophisticated attackers also try to collect sensitive data that we may request when verifying an account holder’s identity. We found 82% of blackhat phishing tools and 74% of keyloggers attempted to collect a user’s IP address and location, while another 18% of tools collected phone numbers and device make and model.

By ranking the relative risk to users, we found that phishing posed the greatest threat, followed by keyloggers, and finally third-party breaches.

Protecting our users from account takeover

Our findings were clear: enterprising hijackers are constantly searching for, and are able to find, billions of different platforms’ usernames and passwords on black markets. While we have already applied these insights to our existing protections, our findings are yet another reminder that we must continuously evolve our defenses in order to stay ahead of these bad actors and keep users safe.

For many years, we’ve applied a ‘defense in-depth’ approach to security—a layered series of constantly improving protections that automatically prevent, detect, and mitigate threats to keep your account safe.

Prevention

 A wide variety of safeguards help us to prevent attacks before they ever affect our users. For example, Safe Browsing, which now protects more than 3 billion devices, alerts users before they visit a dangerous site or when they click a link to a dangerous site within Gmail. We recently announced the Advanced Protection program which provides extra security for users that are at elevated risk of attack.

Detection

 We monitor every login attempt to your account for suspicious activity. When there is a sign-in attempt from a device you’ve never used, or a location you don’t commonly access your account from, we’ll require additional information before granting access to your account. For example, if you sign in from a new laptop and you have a phone associated with you account, you will see a prompt—we’re calling these dynamic verification challenges—like this:
This challenge provides two-factor authentication on all suspicious logins, while mitigating the risk of account lockout.

Mitigation

Finally, we regularly scan activity across Google’s suite of products for suspicious actions performed by hijackers and when we find any, we lock down the affected accounts to prevent any further damage as quickly as possible. We prevent or undo actions we attribute to account takeover, notify the affected user, and help them change their password and re-secure their account into a healthy state.

What you can do

There are some simple steps you can take that make these defenses even stronger. Visit our Security Checkup to make sure you have recovery information associated with your account, like a phone number. Allow Chrome to automatically generate passwords for your accounts and save them via Smart Lock. We’re constantly working to improve these tools, and our automatic protections, to keep your data safe.