Vulnerability identifier: #VU42738

Vulnerability risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2013-4787

CWE-ID: CWE-310

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Google Android
Operating systems & Components / Operating system

Vendor: Google

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

Android 1.6 Donut through 4.2 Jelly Bean does not properly check cryptographic signatures for applications, which allows attackers to execute arbitrary code via an application package file (APK) that is modified in a way that does not violate the cryptographic signature, probably involving multiple entries in a Zip file with the same name in which one entry is validated but the other entry is installed, aka Android security bug 8219321 and the "Master Key" vulnerability.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Google Android: 1.6, 2.0 - 2.3.7, 3.0 - 3.2.6, 4.0 - 4.2

---

External links
http://bluebox.com/corporate-blog/bluebox-uncovers-android-master-key/
http://review.cyanogenmod.org/#/c/45251/
http://www.osvdb.org/94773
http://www.securityfocus.com/bid/60952
http://www.zdnet.com/google-releases-fix-to-oems-for-blue-security-android-security-hole-7000017782/
http://jira.cyanogenmod.org/browse/CYAN-1602
http://plus.google.com/113331808607528811927/posts/GxDA6111vYy

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.