193 lines
7.7 KiB
HTML
193 lines
7.7 KiB
HTML
<html devsite>
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<head>
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<title>Android Security Advisory — 2016-03-18</title>
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<meta name="project_path" value="/_project.yaml" />
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<meta name="book_path" value="/_book.yaml" />
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</head>
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<body>
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<!--
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Copyright 2017 The Android Open Source Project
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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<p><em>Published March 18, 2016</em></p>
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<p>Android Security Advisories are supplemental to the Nexus Security Bulletins.
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Refer to our <a href="index.html">summary page</a> for more information about Security Advisories.</p>
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<h2 id=summary>Summary</h2>
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<p>Google has become aware of a rooting application using an unpatched local
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elevation of privilege vulnerability in the kernel on some Android devices
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(<a href="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1805">CVE-2015-1805</a>).
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For this application to affect a device, the user must first install it. Google
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already blocks installation of rooting applications that use this
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vulnerability — both within Google Play and outside of Google
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Play — using <a href="https://support.google.com/accounts/answer/2812853">
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Verify Apps</a>, and have updated our systems to detect applications that use
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this specific vulnerability.</p>
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<p>To provide a final layer of defense for this issue, partners were provided
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with a patch for this issue on March 16, 2016. Nexus updates are being created
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and will be released within a few days. Source code patches for this issue have
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been released to the Android Open Source Project (AOSP) repository.</p>
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<h3 id=background>Background</h3>
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<p>This is a known issue in the upstream Linux kernel that was fixed in April 2014
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but wasn’t called out as a security fix and assigned
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<a href="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1805">CVE-2015-1805</a>
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until February 2, 2015. On February 19, 2016, C0RE Team notified Google that
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the issue could be exploited on Android and a patch was developed to be included
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in an upcoming regularly scheduled monthly update.</p>
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<p>On March 15, 2016 Google received a
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report from Zimperium that this vulnerability had been abused on a Nexus 5
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device. Google has confirmed the existence of a publicly available rooting
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application that abuses this vulnerability on Nexus 5 and Nexus 6 to provide
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the device user with root privileges.</p>
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<p>This issue is rated as a
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<a href="/security/overview/updates-resources.html#severity">
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Critical severity issue</a> due to the possibility of a local privilege escalation
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and arbitrary code execution leading to local permanent device compromise.</p>
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<h3 id=scope>Scope</h3>
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<p>This advisory applies to all unpatched Android devices on kernel versions 3.4,
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3.10 and 3.14, including all Nexus devices. Android devices using Linux kernel
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version 3.18 or higher are not vulnerable.</p>
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<h3 id=mitigations>Mitigations</h3>
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<p>The following are mitigations that reduce the likelihood users are impacted
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by this issue: </p>
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<ul>
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<li> Verify Apps has been updated to block the installation of applications that
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we have learned are attempting to exploit this vulnerability both within and outside
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of Google Play.
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<li> Google Play does not allow rooting applications, like the one seeking to
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exploit this issue.
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<li> Android devices using <a href="https://support.google.com/nexus/answer/4457705">
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Linux kernel version 3.18</a> or higher are not vulnerable.
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</ul>
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<h3 id=acknowledgements>Acknowledgements</h3>
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<p>Android would like to thank the <a href="http://c0reteam.org/">C0RE Team</a> and
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<a href="https://www.zimperium.com/">Zimperium</a> for their contributions to
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this advisory.</p>
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<h3 id=suggested_actions>Suggested actions</h3>
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<p>Android encourages all users to accept updates to their devices when they
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are available.</p>
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<h3 id=fixes>Fixes</h3>
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<p>Google has released a fix in the AOSP repository for multiple kernel versions.
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Android partners have been notified of these fixes and are encouraged to apply
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them. If further updates are required, Android will publish them directly to ASOP.</p>
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<table>
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<tr>
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<th>Kernel Version</th>
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<th>Patch</th>
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</tr>
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<tr>
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<td>3.4</td>
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<td><a href="https://android.googlesource.com/kernel/common/+/f7ebfe91b806501808413c8473a300dff58ddbb5">AOSP patch</a></td>
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</tr>
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<tr>
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<td>3.10</td>
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<td><a href="https://android.googlesource.com/kernel/common/+/4a5a45669796c5b4617109182e25b321f9f00beb">AOSP patch</a></td>
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</tr>
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<tr>
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<td>3.14</td>
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<td><a href="https://android.googlesource.com/kernel/common/+/bf010e99c9bc48002f6bfa1ad801a59bf996270f">AOSP patch</a></td>
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</tr>
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<tr>
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<td>3.18+</td>
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<td>Patched in public Linux kernel</td>
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</tr>
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</table>
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<h2 id=common_questions_and_answers>Common Questions and Answers</h2>
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<p><strong>1. What's the problem?</strong></p>
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<p>An elevation of privilege vulnerability in the kernel could enable a local
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malicious application to execute arbitrary code in the kernel. This issue is
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rated as a Critical severity due to the possibility of a local permanent device
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compromise and the device would possibly need to be repaired by re-flashing the
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operating system.</p>
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<p><strong>2. How would an attacker seek to exploit this issue?</strong></p>
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<p>Users who install an application that seeks to exploit this issue are at
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risk. Rooting applications (like the one that is exploiting this issue) are
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prohibited in Google Play, and Google is blocking the installation of
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this application outside of Google Play through Verify Apps. An
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attacker would need to convince a user to manually install an affected
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application.</p>
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<p><strong>3. Which devices could be affected?</strong></p>
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<p>Google has confirmed that this exploit works on Nexus 5 and 6; however all
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unpatched versions of Android contain the vulnerability.</p>
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<p><strong>4. Has Google seen evidence of this vulnerability being abused?</strong></p>
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<p>Yes, Google has seen evidence of this vulnerability being abused on a Nexus 5 using a
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publicly available rooting tool. Google has not observed any exploitation that
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would be classified as “malicious.”</p>
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<p><strong>5. How will you be addressing this issue?</strong></p>
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<p><a href="https://static.googleusercontent.com/media/source.android.com/en//security/reports/Android_WhitePaper_Final_02092016.pdf">
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Google Play</a> prohibits apps attempting to
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exploit this issue. Similarly, Verify Apps blocks the installation of apps
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from outside of Google Play that attempt to exploit this issue. Google Nexus
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devices will also be patched as soon as an update is ready and we’ve notified
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Android partners so they can release similar updates.</p>
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<p><strong>6. How do I know if I have a device that contains a fix for this issue?</strong></p>
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<p>Android has provided two options to our partners to communicate that their
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devices are not vulnerable to this issue. Android devices with a security patch
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level of March 18, 2016 are not vulnerable. Android devices with a security
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patch level of April 2, 2016 and later are not vulnerable to this issue. Refer
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to <a href="https://support.google.com/nexus/answer/4457705">this article</a>
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for instructions on how to check the security patch level.</p>
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<h2 id=revisions>Revisions</h2>
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<ul>
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<li> March 18, 2016: Advisory published.
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</ul>
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</body>
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</html>
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