...stuff I do and things I like...

Tuesday, April 22 2014

Mobile Security News Update April 2014

    Infiltrate has Joshua J. Drake: Researching Android Device Security with the Help of a Droid Army

    IEEE Security and Privacy (academic) has a number of papers: Upgrading Your Android, Elevating My Malware: Privilege Escalation Through Mobile OS Updating; The Peril of Fragmentation: Security Hazards in Android Device Driver Customizations; From Zygote to Morula: Fortifying Weakened ASLR on Android

    ReCon has The Making of the Kosher Phone by Assaf Nativ (CFP not complete yet)

    Hack in the Box Amsterdam has Shellcodes for ARM: Your Pills Don't Work on Me, x86; Exploring and Exploiting iOS Web Browsers; State of the ART: Exploring the New Android KitKat Runtime; On Her Majesty's Secret Service: GRX and a Spy Agency (HITB folks fix your website, finding talks and speakers is sooo hard I almost do not bother to do it - worst conference website I know!!)

    ASIA CCS (academic) has a number of papers: Timothy Vidas, Nicolas Christin: Evading Android Runtime Analysis via Sandbox Detection; Collin Mulliner, William Robertson, Engin Kirda: VirtualSwindle: An Automated Attack Against In-App Billing on Android; Min Zheng, Mingshen Sun, John C.S. Lui: DroidRay: A Security Evaluation System for Customized Android Firmwares; Wenbo Yang, Juanru Li, Yuanyuan Zhang, Yong Li, Junliang Shu, Dawu Gu: APKLancet: Tumor Payload Diagnosis and Purification for Android Applications

Heartbleed and Mobile
    Heartbleed and Android [1] I couldn't find any detailed discussion of Android itself or Android apps being vulnerable to the heartbleed attack. Sure some apps are linked against vulnerable versions of OpenSSL but I couldn't find any attack description. If you know anything specific please email me!

    Checkout reverseheartbleed.com a heartbleed testing service for clients software (e.g., web browsers).

    SMS bulk operators vulnerable to heartbleed, leak 2FA tokens see heise.de (in German)

Personal notes
    I'll be speaking at Duo Tech Talks in Ann Abor, MI (this will be a IoT related talk).

    I'm on a panel about Internet of Things security at The Security of Things Forum in Cambridge, MA.

    Mid-End of May I'll spent some time in the Bay Area for IEEE S&P, with plenty of time afterward to hangout.

    I'm also planning to go to ToorCamp, who else is going?

Thursday, April 17 2014

TOR Bleed

Update 2:
    I scanned Tor starting Friday April 11th and ended Sunday April 13th. I stopped cause I got enough evidence on leaked plain text. I wasn't sure what to do with the data so I was sitting on it for a couple of days but than decided to just blog about it.

    Tor doesn't have too many exitnodes, the nodes I was testing are Tor nodes in general not only exitnodes. Never the less I found a number of vulnerable exitnodes that leak plain text data.

    The Tor Project has started to black list vulnerable nodes.

Tuesday April 7th I started my own investigations of the Heartbleed issue. In this blog post I want to talk about one of the things I've been looking into that is the effect heartbleed has on TOR. TOR heavily uses SSL to encrypt traffic between the various TOR nodes. TOR was obviously vulnerable as reported by the TOR project.

For my investigation I pulled a list of about 5000 TOR nodes using dan.me.uk. Using one of the many proof-of-concept exploits I scanned the TOR nodes to determine if they are vulnerable. I found 1045 of the 5000 nodes to be vulnerable to the heartbleed bug, that is about 20%.

I briefly checked the leaked memory to determine if plain text is leaked that is related to TOR user traffic. Yes, TOR exitnodes that are vulnerable to heartbleed leak plain text user traffic. You can find anything ranging from hostnames, downloaded web content, to session IDs, etc.

The majority of the vulnerable TOR nodes are located in Germany, Russia, France, Netherlands, United Kingdom, and Japan. The TOR network has more than 5000 nodes so this is not a complete picture but it provides a good overview of the possible number of vulnerable exitnodes.

The heartbleed bug basically allows any one to obtain traffic coming in and out of TOR exitnodes (given that the actual connection that is run over TOR is not encrypted itself). Of course a malicious party could run a TOR exitnode and inspect all the traffic that passes thru it, but this requires running a TOR node in the first place. Using the heartbleed bug anyone can query vulnerable exitnodes to obtain TOR exit traffic.

There are a number of possible solutions for this problem. 1) update vulnerable TOR nodes (hopefully in progress), 2) create a blacklist of vulnerable TOR nodes and avoid them, 3) stop using TOR until all nodes are updated.

Further Steps:
    Scan all TOR exitnodes to create a black list of vulnerable nodes so users can avoid them.

    One interesting thing I found is the large number of requests that seem to be originating from malware due to the domain names looking like the output of a DGA.


Wednesday, March 26 2014

Android Hardening Tools

A few weeks ago I upgraded from a Galaxy Nexus to a Nexus 5. I therefore took the chance and investigated lightweight and practical device hardening tools. I didn't have anything specific in mind I just wanted to improve my overall situation. Here is what I came up with.

    File system encryption, of course, using the build-in functionality of Android. To improve the security and usability I use Cyrptfs Password to have a separate passphrase for the file system encryption and the screen lock. This tool requires root.

    Encrypted SMS and messaging using TextSecure. The application is very user friendly and a nice replacement for Google Hangout.

    I started using SSHTunnel and ProxyDroid to secure network traffic while traveling. In combination both tools provide the ability to tunnel all network traffic of your device through any box you have a SSH access on. Both apps require root.

    I'm trying out Pry-fi a Wifi privacy tool.

App Security:
    This category is a little hard to describe. I was looking for an app to vet APK, but without using any AV software. I found Checksum, this app calculates a checksum for each APK and compares it with a global repository that is feed with checksums from other users.

    I further using my own tool TelStop to inspect TEL Uri to determine if the contain MMI codes.

    If I was using an older Android device I would also install: ReKey to patch Master Key and X-Ray to scan for vulnerabilities.

    Many of the hardening apps I use require root access. Rooting is a tricky business and you should only do it if you know what you are getting into. If you want to encrypt and root, first root then encrypt. Rooting a Nexus device is straightforward, unlock the bootloader, install su + superSU. One thing todo is install a recovery image that can handle encrypted file systems like TWRP. A decent guide is posted here.

    You should also consider re-locking your bootloader after rooting, see What's the security implication of having an unlocked boot loader?. This is a lot of work and pretty painful when installing firmware patches, but you likely don't want to run around with a unlocked bootloader.

All together I'm pretty happy with this limited set of security applications. If you think I'm missing something important please let me know.

Monday, March 03 2014

Mobile Security News Update March 2014

    InfoSecSouthWest April 4-6 Austin Texas. jduck: Android Security Research and Testing at Scale. Thomas Wang: Breaking through the bottleneck: Mobile malware is outbreak spreading like wildfire.

TextSecure: secure and easy to use text (SMS) for Android (and soon iOS)
    I'm not really into advertising for stuff here but the recent update of TextSecure made a gigantic impression on me. The application works well, is uber user friendly, and looks just great. They further added IM like functionality (using IP rather then SMS), see here: The New TextSecure: Privacy Beyond SMS. Further there is the possibility to run your own server for TextSecure IP backend, see here.

    I switched to TextSecure for a number of reasons: transparent encrypted SMS, super usable application (I can finally stop using the Hangout app - worst thing so far on my Nexus 5), TextSecure source code is available, and did I mention that the UI looks really great? All in all this is good quality security software that even looks better then the less secure competitors, YES!

WebViews and Security on Android
    The security (insecurity) of WebView lately got a lot of attention. There has been some early academic work such as A View to A Kill: WebView Exploitation by Matthias Neugschwandtner et al. Then there was Dave Hartley's blog post on ad-network security. Most recently Joshua 'jduck' Drake wrote a very detailed blog post about the WebView addJavaScriptInterface Saga. All in all the WebView story is not over for sure as WebViews are a widely used framework feature of Android. I'll keep following this issue for sure.


Saturday, January 25 2014

Mobile Security News Update for February 2014

This is an early update for February. Two reasons, I have stuff to write about right now, second I'm going to be super busy in February.

This year I attended ShmooCon for the first time. I liked it a lot and plan to go again. I didn't know ShmooCon was running for 10 years already. They seem to have a good grip on the conference and don't let it explode in size.

    CanSecWest one of my favorite cons (maybe my #1). Talks: No Apology Required: Deconstructing Blackberry10 - Zach Lanier, Ben Nei ; Duo Security & Accuvant. Outsmarting Bluetooth Smart - Mike Ryan ; iSEC Partners. The Real Deal of Android Device Security: the Third Party - Colin Mulliner, Jon Oberheide ; Northwestern University, Duo Security.

    Troopers (Heidelberg, Germany). There is one mobile talk in the main conference but there in addition they have TelSecDay (invite only) that focuses on Telecommunication security. The main conference talk is: Modern smartphone forensics: Apple iOS: from logical and physical acquisition to iCloud backups, document storage and keychain; encrypted BlackBerry backups (BB 10 and Olympia Service) by Vladimir Katalov.

    nullcon (Goa, India) has a mobile talk this year: Modern smartphone forensics: Apple iCloud, encrypted BlackBerry backups, Windows Phone 8 cloud backup - by Vladimir Katalov.

    SyScan 2014 looks super awesome this year. Josh "Monk" Thomas : "How to train your Snapdragon: Exploring Power Regulation Frameworks on Android". Dr Thaddeus (The) Grugq : "Click and Dragger: Denial and Deception on Android Smartphones". Alex Plaskett & Nick Walker "Navigating a sea of Pwn? : Windows Phone 8 AppSec".


    HITB Amsterdam Shellcodes for ARM: Your Pills Don't Work on Me, x86 by SVETLANA GAIVORONSKI and IVAN PETROV.

    RootedCON (Spain) talks: Raul Siles - iOS: Regreso al futuro, Pau Oliva - Bypassing wifi pay-walls with Android. Some talks look like they are mobile talks too :) (my Spanish is kinda bad)


There are a lot of interesting talks in the next month. I'm working on (and finished) some interesting projects that I can hopefully talk about soon.

Our Android book is finalized and thus should be available in April.

The Defcon CFP is already open so make sure you submit your talks early. Also checkout Area 41 a fine security conference in Switzerland, the CFP is still open.

This year I'm co-chairing ARES an academic security conference. Please consider submitting your papers.

If you are interested in NFC (Near Field Communication) check out the current draft of the Web NFC API. The standard defines how a "web page" can interact with NFC devices.

Sunday, January 05 2014

Mobile Security News Update January 2014

30C3 was awesome. A lot of good talks, many friendly people, and an awesome location. The recordings of all talks can be found here.

The slides and source for my talk Android DDI are available here: slides and source.

I was super busy so I guess I missed a lot that was going on in the 2nd half of December. I will start posting stuff again later this month.

I'm going to ShmooCon in mid January and to Troopers in March.

Advertisement: If you are a computer science student and are interested in security and want to spent some time in the US, please contact me. I'm always looking for motivated people to do research with.

Thursday, November 21 2013

Mobile Security News Update November 2013

    30c3 did not announce the program yet but I know a bunch of people who got their talks accepted. It is going to be a good conference. I will talk about my Dynamic Dalvik Instrumentation framework for Android (more about this soon).

    ShmooCon has announced a number of talks. Armor For Your Android Apps by Roman Faynberg, Apple iOS Certificate Tomfoolery by Tim Medin, How Smart Is Bluetooth Smart? by Mike Ryan, Protecting Sensitive Information on iOS Devices by David Schuetz

News and Links
I bet I missed a lot of stuff that happened in the last weeks.

I'm going to be at 30c3 in Hamburg, Germany between Christmas an New Years.