29 July 2015
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2015.1980 Android Stagefright contains multiple vulnerabilities 29 July 2015 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Android devices Publisher: US-CERT Operating System: Android Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated Access Privileged Data -- Remote/Unauthenticated Resolution: Mitigation CVE Names: CVE-2015-3829 CVE-2015-3828 CVE-2015-3827 CVE-2015-3826 CVE-2015-3824 CVE-2015-1539 CVE-2015-1538 Original Bulletin: http://www.kb.cert.org/vuls/id/924951 Comment: While Google has released an update to correct this issue, it may not be available on all Android devices. A number of workarounds have been provided in this bulletin to mitigate the issue. - --------------------------BEGIN INCLUDED TEXT-------------------- Vulnerability Note VU#924951 Android Stagefright contains multiple vulnerabilities Original Release date: 28 Jul 2015 | Last revised: 28 Jul 2015 Overview Stagefright is the media playback service for Android, introduced in Android 2.2 (Froyo). Stagefright contains multiple vulnerabilities, including several integer overflows, which may allow a remote attacker to execute code on the device. Description According to a Zimperium zLabs blog post, Android's Stagefright engine contains multiple vulnerabilities, including several integer overflows, allowing a remote attacker to access files or possibly execute code on the device. This vulnerability appears to affect all versions of Android from 2.2 (Froyo) and to Android 5.1.1_r5 (Lollipop). ZDNET reports that the feature that makes the vulnerability more severe "appears to be that to reduce video viewing lag time Stagefright automatically processes the video before you even think about watching it." An attacker with a victim's cell phone number may send maliciously crafted multimedia messages (MMS) which may be improperly parsed by the Stagefright tool. Other attack vectors may be possible. According to patches from Google (see patch one, two, three), the vulnerabilities appear to be multiple integer overflows and underflows, and improper integer overflow checks. Since integer overflow is a type of memory error, Address Space Layout Randomization (ASLR) appears to partially mitigate this issue; Forbes reports that Android before 4.1 (Jelly Bean) have "inadequate exploit mitigations." ASLR was introduced in Android 4.0 and fully enabled in Android 4.1. According to Ars Technica, "successful exploits at the very least provide direct access to a phone's audio and camera feeds and to the external storage ... many older phones grant elevated system privileges to Stagefright code, a design that could allow attackers access to many more device resources." Full details are currently not available. Impact A remote attacker may be able to execute code on the Android device. Solution Apply an update Google has released Android 5.1.1_r5 (see patch one, two, three) to address these issues. Note that not all phones with Android 5.1.1 (Lollipop) have this patch applied; patchlevel r5 or above must be installed. While this update has been applied to upstream Android, in the US, cell phone carriers largely control the updating process. The update may or may not be available for your phone. Contact your cell phone carrier or manufacturer for update information. Alternatively, the vulnerability may be mitigated by the following workarounds: Block all text messages from unknown senders Blocking all text messages from unknown senders in your default text message handling app may mitigate this issue. Turn off "Auto Retrieve" for multimedia messages If your default text messaging app does not allow blocking of senders, you may also disable the auto retrieve feature for multimedia messages. This may prevent the autoloading of MMS content into Stagefright. Vendor Information (Learn More) Vendor Status Date Notified Date Updated Amazon Affected - 28 Jul 2015 Barnes and Noble Affected - 28 Jul 2015 Google Affected - 28 Jul 2015 HTC Affected - 28 Jul 2015 Huawei Technologies Affected - 28 Jul 2015 Kyocera Communications Affected - 28 Jul 2015 LG Electronics Affected - 28 Jul 2015 Motorola, Inc. Affected - 28 Jul 2015 Samsung Mobile Affected - 28 Jul 2015 Sony Corporation Affected - 28 Jul 2015 If you are a vendor and your product is affected, let us know. CVSS Metrics (Learn More) Group Score Vector Base 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N Temporal 4.7 E:POC/RL:W/RC:UR Environmental 3.5 CDP:ND/TD:M/CR:ND/IR:ND/AR:ND References http://blog.zimperium.com/experts-found-a-unicorn-in-the-heart-of-android/ http://www.forbes.com/sites/thomasbrewster/2015/07/27/android-text-attacks/ http://www.zdnet.com/article/stagefright-just-how-scary-is-it-for-android-users/ http://arstechnica.com/security/2015/07/950-million-android-phones-can-be-hijacked-by-malicious-text-messages/ https://android.googlesource.com/platform/frameworks/av/+/0e4e5a8%5E!/ https://android.googlesource.com/platform/frameworks/av/+/5c134e6%5E!/ https://android.googlesource.com/platform/frameworks/av/+/030d8d0%5E!/ http://source.android.com/devices/media.html https://www.duosecurity.com/blog/exploit-mitigations-in-android-jelly-bean-4-1 Credit Thanks to Joshua Drake at Zimperiums zLabs for working with Google to publicly disclose this vulnerability. This document was written by Garret Wassermann. Other Information CVE IDs: CVE-2015-1538 CVE-2015-1539 CVE-2015-3824 CVE-2015-3826 CVE-2015-3827 CVE-2015-3828 CVE-2015-3829 Date Public: 21 Jul 2015 Date First Published: 28 Jul 2015 Date Last Updated: 28 Jul 2015 Document Revision: 59 Feedback If you have feedback, comments, or additional information about this vulnerability, please send us email. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to email@example.com and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. 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