1page.title= Security updates and resources
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19<div id="qv-wrapper">
20  <div id="qv">
21    <h2>In this document</h2>
22    <ol id="auto-toc"></ol>
23  </div>
24</div>
25
26<h2 id=android_security_bug_lifecycle>Android security bug lifecycle</h2>
27
28<p>The Android security team is responsible for managing security vulnerabilities
29discovered in the Android platform and many of the core Android apps bundled
30with Android devices.</p>
31
32<p>The Android security team finds security vulnerabilities through internal
33research and also responds to bugs reported by third parties. Sources of
34external bugs include issues reported through the Android Open Source
35Project (AOSP) <a
36href="https://code.google.com/p/android/issues/entry?template=Security%20bug%20report">Security
37bug report</a> template, published and pre-published academic research,
38upstream open source project maintainers, notifications from our device
39manufacturer partners, and publicly disclosed issues posted on blogs or social
40media.</p>
41
42<h2 id=report-issues>Reporting security issues</h2>
43
44<p>Any developer, Android user, or security researcher can notify the Android
45security team of potential security issues through the AOSP bug tracker <a
46href="https://code.google.com/p/android/issues/entry?template=Security%20bug%20report">Security
47bug report</a> template.</p>
48
49<p>Bugs marked as security issues are not externally visible, but they may
50eventually be made visible after the issue is evaluated or resolved. If you
51plan to submit a patch or Compatibility Test Suite (CTS) test to resolve a
52security issue, please attach it to the bug report and wait for a response
53before uploading the code to AOSP.</p>
54
55<h2 id=triaging_bugs>Triaging bugs</h2>
56
57<p>The first task in handling a security vulnerability is to identify the severity
58of the bug and which component of Android is affected. The severity determines
59how the issue is prioritized, and the component determines who fixes the bug,
60who is notified, and how the fix gets deployed to users.</p>
61
62<h3 id=process_types>Process types</h3>
63<p>This table covers the definitions of process types. The process type can be
64defined by the type of application or process or the area in which it runs.
65This table is ordered from least to most privileged.</p>
66<table>
67 <tr>
68    <th>Process type</th>
69    <th>Type definition</th>
70 </tr>
71 <tr>
72    <td>Constrained process</td>
73    <td>A process that runs in a highly limited SELinux domain.<br />
74           OR<br />
75           A process that is significantly more limited than a normal application.</td>
76 </tr>
77 <tr>
78    <td>Unprivileged process</td>
79    <td>A third-party application or process.<br />
80           OR<br />
81          An application or process that runs in the SELinux <code>untrusted_app</code> domain.</td>
82 </tr>
83 <tr>
84    <td>Privileged process</td>
85    <td>An application or process with capabilities that are restricted by SELinux
86        <code>untrusted_app</code> domain.<br />
87         OR<br />
88         An application or process with important privileges that a third-party
89         application cannot obtain.</td>
90 </tr>
91 <tr>
92    <td>Kernel</td>
93    <td>Functionality that is either part of the kernel or runs in the same CPU context
94        as the kernel (like device drivers).</td>
95 </tr>
96 <tr>
97    <td>Trusted Execution Environment (TEE)</td>
98    <td> A component that is designed to be protected from even a hostile kernel.</td>
99 </tr>
100</table>
101
102
103<h3 id=severity>Severity</h3>
104
105
106<p>The severity of a bug generally reflects the potential harm that could occur if
107a bug was successfully exploited. Use the following criteria to determine the
108severity:</p>
109<table>
110 <tr>
111    <th>Rating</th>
112    <th>Consequence of successful exploitation</th>
113 </tr>
114 <tr>
115    <td><strong>Critical</strong></td>
116    <td>
117          <ul>
118             <li> Remote arbitrary code execution in a privileged process
119             <li> Permanent device compromise (device cannot be repaired without re-flashing the
120                  entire operating system)
121             <li> Unauthorized access to data secured by the TEE
122             <li> Remote permanent denial of service (device inoperability: completely permanent
123                  or requiring re-flashing the entire operating system)
124          </ul>
125    </td>
126 </tr>
127 <tr>
128     <td><strong>High</strong></td>
129     <td>
130          <ul>
131             <li> Remote arbitrary code execution in an unprivileged process
132             <li> Remote access to protected data (data normally accessible only to locally
133                  installed apps that request permission, or that is limited to a privileged
134                  process)
135             <li> Remote bypass of user interaction requirements (access to functionality that
136                  would normally require either user initiation or user permission)
137             <li> Local arbitrary code execution in a privileged process
138             <li> Local permanent denial of service (device inoperability: completely permanent
139                  or requiring re-flashing the entire operating system)
140             <li> A general bypass for a kernel level defense in depth or exploit mitigation
141                  technology
142             <li> Remote temporary device denial of service (remote hang or reboot)
143             <li> Local bypass of user interaction requirements for any developer or security
144                  settings modifications
145             <li> A general bypass for operating system protections that isolate application data
146                  from other applications
147             <li> Lockscreen bypass
148        </ul>
149    </td>
150 </tr>
151 <tr>
152     <td><strong>Moderate</strong></td>
153     <td>
154          <ul>
155             <li> Remote arbitrary code execution in a constrained process
156             <li> Local bypass of user interaction requirements (access to functionality that
157                  would normally require either user initiation or user permission)
158             <li> Local temporary denial of service (device requires a factory reset)
159             <li> A general bypass for a user level defense in depth or exploit mitigation
160                  technology in a privileged process
161             <li> Remote access to unprotected data (data normally accessible to any locally
162                  installed app)
163             <li> Bypass of Device Protection/ Factory Reset Protection
164        </ul>
165    </td>
166 </tr>
167 <tr>
168     <td><strong>Low</strong></td>
169     <td>
170          <ul>
171             <li> A general bypass for a user level defense in depth or exploit mitigation
172                  technology in an unprivileged process
173             <li> Local temporary denial of service (can be resolved by booting the device into
174                  Safe Mode and removing the problematic application, or by a factory reset if
175                  the device does not support Safe Mode)
176          </ul>
177     </td>
178 </tr>
179</table>
180
181
182<h4 id=local_vs_remote>Local vs. remote</h4>
183
184<p>A remote attack vector indicates the bug could be exploited without installing
185an app or without physical access to the device. This includes bugs that could
186be triggered by browsing to a web page, reading an email, receiving an SMS
187message, or connecting to a hostile network. For the purpose of our severity
188ratings, the Android security team also considers "proximal" attack vectors as
189remote. These include bugs that can be exploited only by an attacker who is
190physically near the target device, for example a bug that requires sending
191malformed Wi-Fi or Bluetooth packets.</p>
192
193<p>Local attacks require the victim to install an app. For the purpose of severity
194ratings, the Android security team also considers physical attack vectors as
195local. These include bugs that can be exploited only by an attacker who has
196physical access to the device, for example a bug in a lock screen or one that
197requires plugging in a USB cable. The Android security team also considers
198NFC-based attacks as local.</p>
199
200<h3 id=rating_modifiers>Rating modifiers</h3>
201<p>While the severity of security vulnerabilities is often easy to identify,
202ratings may change based on circumstances.  </p>
203<table>
204 <tr>
205    <th>Reason</th>
206    <th>Effect</th>
207 </tr>
208 <tr>
209    <td>Requires running as a privileged process to execute the attack</td>
210    <td>-1 Severity</td>
211 </tr>
212 <tr>
213    <td>Vulnerability-specific details limit the impact of the issue </td>
214    <td>-1 Severity</td>
215 </tr>
216</table>
217
218
219<h3 id=affected_component>Affected component</h3>
220
221<p>The development team responsible for fixing the bug depends on which component
222the bug is in. It could be a core component of the Android platform, a kernel
223driver supplied by an original equipment manufacturer (OEM), or one of the
224pre-loaded apps on Nexus devices.</p>
225
226<p>Bugs in AOSP code are fixed by the Android engineering team. Low-severity bugs,
227bugs in certain components, or bugs that are already publicly known may be
228fixed directly in the publicly available AOSP master branch; otherwise they're
229fixed in our internal repositories first.</p>
230
231<p>The component is also a factor in how users get updates. A bug in the framework
232or kernel will require an over-the-air (OTA) firmware update that each OEM will
233need to push. A bug in an app or library published in Google Play (e.g., Gmail,
234Google Play Services, WebView in Lollipop and later versions) can be sent to
235Android users as an update from Google Play. </p>
236
237<h2 id=notifying_partners>Notifying partners</h2>
238
239<p>When a moderate or higher severity security vulnerability in AOSP is fixed,
240we'll notify Android partners of issue details and provide patches for a minimum
241of the most recent three Android releases. The Android security team currently
242provides patches for Android versions 4.4 (KitKat), 5.0 (Lollipop), 5.1
243(Lollipop MR1), and 6.0 (Marshmallow). This list of backport-supported versions
244changes with each new Android release.</p>
245
246<h2 id=releasing_code_to_aosp>Releasing code to AOSP</h2>
247
248<p>If the security bug is in an AOSP component, the fix will be pushed out to AOSP
249after the OTA is released to users. Fixes for low-severity issues may be
250submitted directly to the AOSP master branch before a fix is available.</p>
251
252<h2 id=android_updates>Receiving Android updates</h2>
253
254<p>Updates to the Android system are generally delivered to devices through
255OTA update packages. These updates may come from the OEM who
256produced the device or the carrier who provides service to the device. Google
257Nexus device updates come from the Google Nexus team after going through a
258carrier technical acceptance (TA) testing procedure. Google also publishes <a
259href="https://developers.google.com/android/nexus/images">Nexus factory
260images</a> that can be side-loaded to devices.</p>
261
262<h2 id=updating_google_services>Updating Google services</h2>
263
264<p>In addition to providing patches for security bugs, the Android security team
265also review security bugs to determine if there are other ways to protect
266users. For example, Google Play scans all applications and will remove any
267application that attempts to exploit a security bug. For applications installed
268from outside of Google Play, devices with Google Play Services may also use the
269<a href="https://support.google.com/accounts/answer/2812853">Verify Apps</a>
270feature to warn users about applications that may be potentially harmful.</p>
271
272<h2 id=other_resources>Other resources</h2>
273
274<p>Information for Android application developers: <a
275href="https://developer.android.com">https://developer.android.com</a></p>
276
277<p>Security information exists throughout the Android Open Source and Developer
278sites. Good places to start:<br>
279<a href="https://source.android.com/security/index.html">https://source.android.com/security/index.html</a><br>
280<a href="https://developer.android.com/training/articles/security-tips.html">https://developer.android.com/training/articles/security-tips.html</a></p>
281
282<h3 id=reports>Reports</h3>
283<p>Sometimes the Android Security team publishes reports or whitepapers. Here are some of the most recent.</p>
284<ul>
285  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_2015_Report_Final.pdf">
286      Android Security 2015 Year In Review</a></li>
287  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_2014_Report_Final.pdf">
288      Android Security 2014 Year In Review</a></li>
289  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android_WhitePaper_Final_02092016.pdf">
290      Android Security white paper</a></li>
291  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Google_Android_Security_PHA_classifications.pdf">
292      Classifications for Potentially Harmful Applications</a></li>
293</ul>
294
295<h3 id=slides>Android Bootcamp 2016 slides</h3>
296<p>The Android Security team has published their Android Bootcamp 2016 slides that cover new security features.</p>
297<ul>
298  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Verified-Boot-and-Encryption.pdf">
299      Verified boot and encryption</a></li>
300  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-SafetyNet.pdf">
301      SafetyNet</a></li>
302  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-New-App-Lifecycle-for-Encryption.pdf">
303      New app life cycle for encryption</a></li>
304  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Keeping-Google-Play-safe.pdf">
305      Keeping Google Play safe</a></li>
306  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Defense-in-depth-efforts.pdf">
307      Defense in depth efforts</a></li>
308  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Android-Keystore-Attestation.pdf">
309      Keystore attestation</a></li>
310  <li><a href="http://static.googleusercontent.com/media/source.android.com/en//security/reports/Android-Bootcamp-2016-Android-Attack-Team.pdf">
311      Android attack team</a></li>
312</ul>
313
314