Date: Sat, 05 Jul 2014 14:32:52 +0200
From: Curesec Research Team <crt@...esec.com>
To: fulldisclosure@...lists.org
Subject: [FD] Conduct phonecalls on Android without the necessary permission,
 advisory+testapplication+exploits for testing (CVE-2013-6272 and
 CVE-2014-N/A)

Hi List,

we are pleased to announce the public disclosure of two new bugs in
Android OS.

1. CVE-2013-6272 com.android.phone

Introduction

We conducted a deep investigation of android components and created some
CVEs and reported bugs to the Android Security Team in late 2013. Today
we want to publish one reported and one similar vulnerability.
Credits

Affectect Versions:
Version 	SDK 	Affected
4.1.1 	16 	Vulnerable
4.1.2 	16 	Vulnerable
4.2.2 	17 	Vulnerable
4.4.2 	19 	Vulnerable
4.4.4 	19 	Not Vulnerable

Please find the full advisory here:
https://blog.curesec.com/article/blog/35.html

2. CVE-2014-N/A com.android.contacts

Introduction

This bug is similar to CVE-2013-6276 but is only exploitable on older
Android versions. The bug exists in the component com.android.contacts.
Credits

Affectect Versions:

Version 	SDK 	Affected
2.3.3 	10 	Vulnerable
2.3.6 	10 	Vulnerable
3.0 	11 	Not Vulnerable
3.2 	13 	Not Vulnerable
4.0 	14 	Not Vulnerable
4.0.3 	15 	Not Vulnerable

This bug is not related to CVE-2013-6276 but has the same result.
Reading the source code it probably exists at least from version 1.5.
However we have only tested with SDK 10.

Please find the full advisory here:
https://blog.curesec.com/article/blog/36.html

- FAQ -
1. Why is this a bug?
Android normally has to grant permission so that your applications can
conduct actions. If your installed application does not own the right to
do a phone call, the Android OS should throw a permission denied.

However this bug is circumventing the situation and allows any malicous
app to do a phone call, send mmi or ussd codes or hangup an ongoing call.

2. Is there an app to test this issue on my phone?
You can use the APK we published. You will find details in the next
sections.

3. How would an attacker abuse this?
This bug can be abused by a malicious application. Take a simple game
which is coming with this code. The game wont ask you for extra
permissions to do a phone call to a toll number - but it is able to do it.

This is normally not possible without giving the app this special
permission. But not only might it be disturbing or expensive for someone
to call a toll number or getting ongoing calls hung up. It is also
possible to send USSD codes.

The list of USSD/SS/MMI codes is long and there are several quite
powerful ones like changing the flow of phone calls(forwarding),
blocking your simcard, enable or disable caller anonymisation and so on.

Please note that Curesec GmbH is not responsible for any damage your
device might suffer while you try to execute such codes.

4. Are tools which revoke permissions from apps blocking this attack?
No. As the app does not have the permission but is abusing a bug, such
apps cannot easily protect you from this without the knowledge that this
bug exists in another class on the system.

5. How can I contact you?

security@...esec.com

Downloads:
http://www.curesec.com/data/CRT-Kolme.apk -- Test application
http://www.curesec.com/data/CRT-Kolme.7z -- Source code
http://www.curesec.com/data/dz_exploits.tar.bz2 -- exploits for drozer

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