path: root/src/security/overview/updates-resources.jd

page.title= Security updates and resources
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<div id="qv-wrapper">
  <div id="qv">
    <h2>In this document</h2>
    <ol id="auto-toc"></ol>
  </div>
</div>

<h2 id=android_security_bug_lifecycle>Android security bug lifecycle</h2>

<p>The Android security team is responsible for managing security vulnerabilities
discovered in the Android platform and many of the core Android apps bundled
with Android devices.</p>

<p>The Android security team finds security vulnerabilities through internal
research and also responds to bugs reported by third parties. Sources of
external bugs include issues reported through the Android Open Source
Project (AOSP) <a
href="https://code.google.com/p/android/issues/entry?template=Security%20bug%20report">Security
bug report</a> template, published and pre-published academic research,
upstream open source project maintainers, notifications from our device
manufacturer partners, and publicly disclosed issues posted on blogs or social
media.</p>

<h2 id=report-issues>Reporting security issues</h2>

<p>Any developer, Android user, or security researcher can notify the Android
security team of potential security issues through the AOSP bug tracker <a
href="https://code.google.com/p/android/issues/entry?template=Security%20bug%20report">Security
bug report</a> template.</p>

<p>Bugs marked as security issues are not externally visible, but they may
eventually be made visible after the issue is evaluated or resolved. If you
plan to submit a patch or Compatibility Test Suite (CTS) test to resolve a
security issue, please attach it to the bug report and wait for a response
before uploading the code to AOSP.</p>

<h2 id=triaging_bugs>Triaging bugs</h2>

<p>The first task in handling a security vulnerability is to identify the severity
of the bug and which component of Android is affected. The severity determines
how the issue is prioritized, and the component determines who fixes the bug,
who is notified, and how the fix gets deployed to users.</p>

<h3 id=process_types>Process types</h3>
<p>This table covers the definitions of process types. The process type can be
defined by the type of application or process or the area in which it runs.
This table is ordered from least to most privileged.</p>
<table>
 <tr>
    <th>Process type</th>
    <th>Type definition</th>
 </tr>
 <tr>
    <td>Constrained process</td>
    <td>A process that runs in a highly limited SELinux domain.<br />
           OR<br />
           A process that is significantly more limited than a normal application.</td>
 </tr>
 <tr>
    <td>Unprivileged process</td>
    <td>A third-party application or process.<br />
           OR<br />
          An application or process that runs in the SELinux <code>untrusted_app</code> domain.</td>
 </tr>
 <tr>
    <td>Privileged process</td>
    <td>An application or process with capabilities that are restricted by SELinux
        <code>untrusted_app</code> domain.<br />
         OR<br />
         An application or process with important privileges that a third-party
         application cannot obtain.</td>
 </tr>
 <tr>
    <td>Kernel</td>
    <td>Functionality that is either part of the kernel or runs in the same CPU context
        as the kernel (like device drivers).</td>
 </tr>
 <tr>
    <td>Trusted Execution Environment (TEE)</td>
    <td> A component that is designed to be protected from even a hostile kernel.</td>
 </tr>
</table>


<h3 id=severity>Severity</h3>


<p>The severity of a bug generally reflects the potential harm that could occur if
a bug was successfully exploited. Use the following criteria to determine the
severity:</p>
<table>
 <tr>
    <th>Rating</th>
    <th>Consequence of successful exploitation</th>
 </tr>
 <tr>
    <td><strong>Critical</strong></td>
    <td>
          <ul>
             <li> Remote arbitrary code execution in a privileged process
             <li> Permanent device compromise (device cannot be repaired without re-flashing the
                  entire operating system)
             <li> Unauthorized access to data secured by the TEE
             <li> Remote permanent denial of service (device inoperability: completely permanent
                  or requiring re-flashing the entire operating system)
          </ul>
    </td>
 </tr>
 <tr>
     <td><strong>High</strong></td>
     <td>
          <ul>
             <li> Remote arbitrary code execution in an unprivileged process
             <li> Remote access to protected data (data normally accessible only to locally
                  installed apps that request permission, or that is limited to a privileged
                  process)
             <li> Remote bypass of user interaction requirements (access to functionality that
                  would normally require either user initiation or user permission)
             <li> Local arbitrary code execution in a privileged process
             <li> Local permanent denial of service (device inoperability: completely permanent
                  or requiring re-flashing the entire operating system)
             <li> A general bypass for a kernel level defense in depth or exploit mitigation
                  technology
             <li> Remote temporary device denial of service (remote hang or reboot)
             <li> Local bypass of user interaction requirements for any developer or security
                  settings modifications
             <li> A general bypass for operating system protections that isolate application data
                  from other applications
             <li> Lockscreen bypass
        </ul>
    </td>
 </tr>
 <tr>
     <td><strong>Moderate</strong></td>
     <td>
          <ul>
             <li> Remote arbitrary code execution in a constrained process
             <li> Local bypass of user interaction requirements (access to functionality that
                  would normally require either user initiation or user permission)
             <li> Local temporary denial of service (device requires a factory reset)
             <li> A general bypass for a user level defense in depth or exploit mitigation
                  technology in a privileged process
             <li> Remote access to unprotected data (data normally accessible to any locally
                  installed app)
             <li> Bypass of Device Protection/ Factory Reset Protection
        </ul>
    </td>
 </tr>
 <tr>
     <td><strong>Low</strong></td>
     <td>
          <ul>
             <li> A general bypass for a user level defense in depth or exploit mitigation
                  technology in an unprivileged process
             <li> Local temporary denial of service (can be resolved by booting the device into
                  Safe Mode and removing the problematic application, or by a factory reset if
                  the device does not support Safe Mode)
          </ul>
     </td>
 </tr>
</table>


<h4 id=local_vs_remote>Local vs. remote</h4>

<p>A remote attack vector indicates the bug could be exploited without installing
an app or without physical access to the device. This includes bugs that could
be triggered by browsing to a web page, reading an email, receiving an SMS
message, or connecting to a hostile network. For the purpose of our severity
ratings, the Android security team also considers "proximal" attack vectors as
remote. These include bugs that can be exploited only by an attacker who is
physically near the target device, for example a bug that requires sending
malformed Wi-Fi or Bluetooth packets.</p>

<p>Local attacks require the victim to install an app. For the purpose of severity
ratings, the Android security team also considers physical attack vectors as
local. These include bugs that can be exploited only by an attacker who has
physical access to the device, for example a bug in a lock screen or one that
requires plugging in a USB cable. The Android security team also considers
NFC-based attacks as local.</p>

<h3 id=rating_modifiers>Rating modifiers</h3>
<p>While the severity of security vulnerabilities is often easy to identify,
ratings may change based on circumstances.  </p>
<table>
 <tr>
    <th>Reason</th>
    <th>Effect</th>
 </tr>
 <tr>
    <td>Requires running as a privileged process to execute the attack</td>
    <td>-1 Severity</td>
 </tr>
 <tr>
    <td>Vulnerability-specific details limit the impact of the issue </td>
    <td>-1 Severity</td>
 </tr>
</table>


<h3 id=affected_component>Affected component</h3>

<p>The development team responsible for fixing the bug depends on which component
the bug is in. It could be a core component of the Android platform, a kernel
driver supplied by an original equipment manufacturer (OEM), or one of the
pre-loaded apps on Nexus devices.</p>

<p>Bugs in AOSP code are fixed by the Android engineering team. Low-severity bugs,
bugs in certain components, or bugs that are already publicly known may be
fixed directly in the publicly available AOSP master branch; otherwise they're
fixed in our internal repositories first.</p>

<p>The component is also a factor in how users get updates. A bug in the framework
or kernel will require an over-the-air (OTA) firmware update that each OEM will
need to push. A bug in an app or library published in Google Play (e.g., Gmail,
Google Play Services, WebView in Lollipop and later versions) can be sent to
Android users as an update from Google Play. </p>

<h2 id=notifying_partners>Notifying partners</h2>

<p>When a moderate or higher severity security vulnerability in AOSP is fixed,
we'll notify Android partners of issue details and provide patches for a minimum
of the most recent three Android releases. The Android security team currently
provides patches for Android versions 4.4 (KitKat), 5.0 (Lollipop), 5.1
(Lollipop MR1), and 6.0 (Marshmallow). This list of backport-supported versions
changes with each new Android release.</p>

<h2 id=releasing_code_to_aosp>Releasing code to AOSP</h2>

<p>If the security bug is in an AOSP component, the fix will be pushed out to AOSP
after the OTA is released to users. Fixes for low-severity issues may be
submitted directly to the AOSP master branch before a fix is available.</p>

<h2 id=android_updates>Receiving Android updates</h2>

<p>Updates to the Android system are generally delivered to devices through
OTA update packages. These updates may come from the OEM who
produced the device or the carrier who provides service to the device. Google
Nexus device updates come from the Google Nexus team after going through a
carrier technical acceptance (TA) testing procedure. Google also publishes <a
href="https://developers.google.com/android/nexus/images">Nexus factory
images</a> that can be side-loaded to devices.</p>

<h2 id=updating_google_services>Updating Google services</h2>

<p>In addition to providing patches for security bugs, the Android security team
also review security bugs to determine if there are other ways to protect
users. For example, Google Play scans all applications and will remove any
application that attempts to exploit a security bug. For applications installed
from outside of Google Play, devices with Google Play Services may also use the
<a href="https://support.google.com/accounts/answer/2812853">Verify Apps</a>
feature to warn users about applications that may be potentially harmful.</p>

<h2 id=other_resources>Other resources</h2>

<p>Information for Android application developers: <a
href="https://developer.android.com">https://developer.android.com</a></p>

<p>Security information exists throughout the Android Open Source and Developer
sites. Good places to start:<br>
<a href="https://source.android.com/security/index.html">https://source.android.com/security/index.html</a><br>
<a href="https://developer.android.com/training/articles/security-tips.html">https://developer.android.com/training/articles/security-tips.html</a></p>

<h3 id=reports>Reports</h3>
<p>Sometimes the Android Security team publishes reports or whitepapers. Here are some of the most recent.</p>
<ul>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_2015_Report_Final.pdf">
      Android Security 2015 Year In Review</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_2014_Report_Final.pdf">
      Android Security 2014 Year In Review</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android_WhitePaper_Final_02092016.pdf">
      Android Security white paper</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_PHA_classifications.pdf">
      Classifications for Potentially Harmful Applications</a></li>
</ul>

<h3 id=slides>Android Bootcamp 2016 slides</h3>
<p>The Android Security team has published their Android Bootcamp 2016 slides that cover new security features.</p>
<ul>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Verified-Boot-and-Encryption.pdf">
      Verified boot and encryption</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-SafetyNet.pdf">
      SafetyNet</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-New-App-Lifecycle-for-Encryption.pdf">
      New app life cycle for encryption</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Keeping-Google-Play-safe.pdf">
      Keeping Google Play safe</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Defense-in-depth-efforts.pdf">
      Defense in depth efforts</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Android-Keystore-Attestation.pdf">
      Keystore attestation</a></li>
  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Android-Attack-Team.pdf">
      Android attack team</a></li>
</ul>