Nexus Security Bulletin - November 2015

In this document

Published November 02, 2015

We have released a security update to Nexus devices through an over-the-air (OTA) update as part of our Android Security Bulletin Monthly Release process. The Nexus firmware images have also been released to the Google Developer site. Builds LMY48X or later and Android Marshmallow with Security Patch Level of November 1, 2015 or later address these issues. Refer to the Common Questions and Answers section for more details.

Partners were notified about these issues on October 5, 2015 or earlier. Source code patches for these issues will be released to the Android Open Source Project (AOSP) repository over the next 48 hours. We will revise this bulletin with the AOSP links when they are available.

The most severe of these issues is a Critical security vulnerability that could enable remote code execution on an affected device through multiple methods such as email, web browsing, and MMS when processing media files.

We have had no reports of active customer exploitation of these newly reported issues. Refer to the Mitigations section for details on the Android security platform protections and service protections such as SafetyNet, which improve the security of the Android platform. We encourage all customers to accept these updates to their devices.

Security Vulnerability Summary

The table below contains a list of security vulnerabilities, the Common Vulnerability and Exposures ID (CVE), and their assessed severity. The severity assessment is based on the effect that exploiting the vulnerability would have on an affected device, assuming the platform and service mitigations are disabled for development purposes or if successfully bypassed.

Issue CVE Severity
Remote Code Execution Vulnerabilities in Mediaserver CVE-2015-6608 Critical
Remote Code Execution Vulnerability in libutils CVE-2015-6609 Critical
Information Disclosure Vulnerabilities in Mediaserver CVE-2015-6611 High
Elevation of Privilege Vulnerability in libstagefright CVE-2015-6610 High
Elevation of Privilege Vulnerability in libmedia CVE-2015-6612 High
Elevation of Privilege Vulnerability in Bluetooth CVE-2015-6613 High
Elevation of Privilege Vulnerability in Telephony CVE-2015-6614 Moderate

The severity assessment is based on the effect that exploiting the vulnerability would have on an affected device, assuming the platform and service mitigations are disabled for development purposes or if successfully bypassed.

Mitigations

This is a summary of the mitigations provided by the Android security platform and service protections such as SafetyNet. These capabilities reduce the likelihood that security vulnerabilities can be successfully exploited on Android.

  • Exploitation for many issues on Android is made more difficult by enhancements in newer versions of the Android platform. We encourage all users to update to the latest version of Android where possible.
  • The Android Security team is actively monitoring for abuse with Verify Apps and SafetyNet which will warn about potentially harmful applications about to be installed. Device rooting tools are prohibited within Google Play. To protect users who install applications from outside of Google Play, Verify Apps is enabled by default and will warn users about known rooting applications. Verify Apps attempts to identify and block installation of known malicious applications that exploit a privilege escalation vulnerability. If such an application has already been installed, Verify Apps will notify the user and attempt to remove any such applications.
  • As appropriate, Google Hangouts and Messenger applications do not automatically pass media to processes such as mediaserver.

Acknowledgements

We would like to thank these researchers for their contributions:

  • Abhishek Arya, Oliver Chang and Martin Barbella, Google Chrome Security Team: CVE-2015-6608
  • Daniel Micay (daniel.micay@copperhead.co) at Copperhead Security: CVE-2015-6609
  • Dongkwan Kim of System Security Lab, KAIST (dkay@kaist.ac.kr): CVE-2015-6614
  • Hongil Kim of System Security Lab, KAIST (hongilk@kaist.ac.kr): CVE-2015-6614
  • Jack Tang of Trend Micro (@jacktang310): CVE-2015-6611
  • Peter Pi of Trend Micro: CVE-2015-6611
  • Natalie Silvanovich of Google Project Zero: CVE-2015-6608
  • Qidan He (@flanker_hqd) and Wen Xu (@antlr7) from KeenTeam (@K33nTeam, http://k33nteam.org/): CVE-2015-6612
  • Guang Gong (龚广) (@oldfresher, higongguang@gmail.com) of Qihoo 360 Technology CC o.Ltd: CVE-2015-6612
  • Seven Shen of Trend Micro: CVE-2015-6610

Security Vulnerability Details

In the sections below, we provide details for each of the security vulnerabilities listed in the Security Vulnerability Summary above. There is a description of the issue, a severity rationale, and a table with the CVE, associated bug, severity, affected versions, and date reported. Where available, we’ve linked the AOSP change that addressed the issue to the bug ID. When multiple changes relate to a single bug, additional AOSP references are linked to numbers following the bug ID.

Remote Code Execution Vulnerabilities in Mediaserver

During media file and data processing of a specially crafted file, vulnerabilities in mediaserver could allow an attacker to cause memory corruption and remote code execution as the mediaserver process.

The affected functionality is provided as a core part of the operating system and there are multiple applications that allow it to be reached with remote content, most notably MMS and browser playback of media.

This issue is rated as a Critical severity due to the possibility of remote code execution within the context of the mediaserver service. The mediaserver service has access to audio and video streams as well as access to privileges that third-party apps cannot normally access.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6608 ANDROID-19779574 Critical 5.0, 5.1, 6.0 Google Internal
ANDROID-23680780
ANDROID-23876444
ANDROID-23881715 Critical 4.4, 5.0, 5.1, 6.0 Google Internal
ANDROID-14388161 Critical 4.4 and 5.1 Google Internal
ANDROID-23658148 Critical 5.0, 5.1, 6.0 Google Internal

Remote Code Execution Vulnerability in libutils

A vulnerability in libutils, a generic library, can be exploited during audio file processing. This vulnerability could allow an attacker, during processing of a specially crafted file, to cause memory corruption and remote code execution.

The affected functionality is provided as an API and there are multiple applications that allow it to be reached with remote content, most notably MMS and browser playback of media. This issue is rated as a Critical severity issue due to the possibility of remote code execution in a privileged service. The affected component has access to audio and video streams as well as access to privileges that third-party apps cannot normally access.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6609 ANDROID-22953624 [2] Critical 6.0 and below Aug 3, 2015

Information Disclosure Vulnerabilities in Mediaserver

There are information disclosure vulnerabilities in mediaserver that can permit a bypass of security measures in place to increase the difficulty of attackers exploiting the platform.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6611 ANDROID-23905951 [2] [3] High 6.0 and below Sep 07, 2015
ANDROID-23912202*
ANDROID-23953967*
ANDROID-23696300 High 6.0 and below Aug 31, 2015
ANDROID-23600291 High 6.0 and below Aug 26, 2015
ANDROID-23756261 [2] High 6.0 and below Aug 26, 2015
ANDROID-23540907 [2] High 5.1 and below Aug 25, 2015
ANDROID-23541506 High 6.0 and below Aug 25, 2015
ANDROID-23284974*
ANDROID-23542351*
ANDROID-23542352*
ANDROID-23515142 High 5.1 and below Aug 19, 2015

* The patch for this bug is included in other provided AOSP links.

Elevation of Privilege Vulnerability in libstagefright

There is an elevation of privilege vulnerability in libstagefright that can enable a local malicious application to cause memory corruption and arbitrary code execution within the context of the mediaserver service. While this issue would normally be rated Critical, we have assessed this issue as High severity because of a lower likelihood that it can be exploited remotely.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6610 ANDROID-23707088 [2] High 6.0 and below Aug 19, 2015

Elevation of Privilege Vulnerability in libmedia

There is a vulnerability in libmedia that can enable a local malicious application to execute arbitrary code within the context of the mediaserver service. This issue is rated as High severity because it can be used to access privileges which are not directly accessible to a third-party application.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6612 ANDROID-23540426 High 6.0 and below Aug 23, 2015

Elevation of Privilege Vulnerability in Bluetooth

There is a vulnerability in Bluetooth that can enable a local application to send commands to a listening debug port on the device. This issue is rated as High severity because it can be used to gain elevated capabilities, such as Signature or SignatureOrSystem permissions privileges, which are not accessible to a third-party application.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6613 ANDROID-24371736 High 6.0 Google Internal

Elevation Of Privilege Vulnerability in Telephony

A vulnerability in the Telephony component that can enable a local malicious application to pass unauthorized data to the restricted network interfaces, potentially impacting data charges. It could also prevent the device from receiving calls as well as allowing an attacker to control the mute settings of calls. This issue is rated as Moderate severity because it can be used to improperly gain “dangerous” permissions.

CVE Bug(s) with AOSP links Severity Affected versions Date reported
CVE-2015-6614 ANDROID-21900139 [2] [3] Moderate 5.0, 5.1 Jun 8, 2015

Common Questions and Answers

This section will review answers to common questions that may occur after reading this bulletin.

1. How do I determine if my device is updated to address these issues?

Builds LMY48X or later and Android Marshmallow with Security Patch Level of November 1, 2015 or later address these issues. Refer to the Nexus documentation for instructions on how to check the security patch level. Device manufacturers that include these updates should set the patch string level to: [ro.build.version.security_patch]:[2015-11-01]

Revisions

  • November 02, 2015: Originally Published