Mobile Device Security Challenges

Wednesday, February 23, 2011

Danny Lieberman


It has been said that there is nothing new under the sun and that every generation forgets or never learned the hard-earned lessons from the spilled blood of the previous generation.

Reviewing the security and compliance issues  of a new mobile medical device recently, I was struck by how familiar many of the themes are.

What makes mobile devices special? Actually nothing.

Deploying line of business or life science applications on mobile Android tablets or an iPad has a different set of security requirements than backing up your address book. It requires thinking about the software security and privacy vulnerabilities in a systematic way.

However, a software security assessment of a life science software application deployed on a mobile device needs to look beyond the malware and spyware and data breach attacks on the device.

Mobile Android tablets or iPads running electronic medical records applications are usually deployed in uncontrolled, complex and highly vulnerable environments such as enterprise IT networks in hospitals.  

The software security issues are much more severe than those of a single tablet:   a combination of network vulnerabilities, application software vulnerabilities, malicious attackers superimposed on  the large, complex threat surface of an enterprise IT network.

The mobile medical device is now an attack vector into the hospital network, a far more valuable asset than the mobile device itself.

It seems that there are 5 key areas of vulnerability for  mobile devices, but not surprising, they all coincide with the classic IT network vulnerabilities:

Protocol coverage is lacking: Mobile  devices often rely on built-in  firewalls or enterprise network isolation. The protection that firewalls provide is only as good as the policy they are configured to implement and there are a whole slew of issues related to remote security policy management of untethered devices. 

I expect that analysis of network exploits on mobile devices with internal firewalls, will match analysis of real-world configuration data from corporate firewalls  that shows  rule sets that frequently violate well-established security guidelines (for example zone-spanning objects and lack of stealth rules).

In addition, a stateful inspection firewall on a mobile device doesn’t perform deep content inspection on complete sessions and is therefore blind  to data theft attacks – for example piggy-back attacks  on text messaging in order to steal sensitive data.

Proxy-based access to control a device is convenient but may enable attackers to compromise a device and steal data – proxies end-point devices to obtain direct access to the Internet – research with clients show us that as much as 20 percent of all endpoints already bypass content filtering proxies on the enterprise IT network.

Visibility of network transactions is usually missing making incident response very difficult: Firewall and proxy logs are generally never analyzed, and often lag hours behind an event. An IPS often relies on anomaly detection. Anomaly detection relies on network flow data, which is often reported at intervals of 15 to 45 minutes. With that kind of lag, an entire network can be brought down.

Because anomaly detection is looking for an anomalous event rather than an attack, it is frequently plagued by time-consuming false positives. A proxy on the other hand relies on URL filtering and simple keyword matching that analyzes the HTTP header and URL string. By looking at content and ignoring the network; a proxy can suffer from high rates of false negatives, missing attacks.

Multiple security and application layers increases cost of implementation and maintenance. Installation of multiple, disparate, proxy-based security products complicate network and end-point maintenance. Proxies require changes to the network infrastructure and in large networks may be impossible to install.  

Updating mobile device application software to latest patch levels can be challenging to enforce and control and may result in injecting new software vulnerabilities into the device as there is probably not central IT administrator in charge of updating the mobile electronic medical records application running on 300 Android tablets in the hospital.

Redundant, multiple network security elements increase risk in the overall solution: This is additional risk that manifests itself as a result of the interaction between  mobile devices accessing cloud services via  a complex system of cache servers, SSL accelerators, Load balancers, Reverse proxy servers, transparent proxies, IDS/IPS and Web Application Firewalls.

Consider that endpoints can bypass SSL proxies by specifying a gateway IP address and transparent proxies on a Windows network are no assurance for unauthenticated user agents bypassing the entire proxy infrastructure. HTTP-Aware firewalls such as Web application firewalls can be completely or partially bypassed in some cases.

Transparent proxies can be compromised by techniques of HTTP response splitting since they rely on fine-grained mechanisms of matching strings in HTTP headers.  This is why Mozilla is delaying their implementation of Web sockets which may not matter if you’re running Chrome OS.

It’s a new dawn but with old rules.

Cross-posted from Israeli Software

Possibly Related Articles:
PDAs/Smart Phones
HTTP Security SSL Mobile Devices Security Protocols IDS/IPS
Post Rating I Like this!
Franc Schiphorst Some of the problems with the pads (droid or other) is the fact that a lot of them have phone/3g capabilities, you already mentioned text based messages (that are already abused today)

Biggest problem is that contrary to pc based devices, the hardware is only partialy under control. With a tablet you can run your own build of win/nix or what you want. With an iPad you run what steve wants you to run or you have to jailbreak the device. Same for android.

And protection of an android phone goes against it's security concept. Apps runs in a sandbox. So a security scanner basically says all your base are belong to us.

It's a challange :)
The views expressed in this post are the opinions of the Infosec Island member that posted this content. Infosec Island is not responsible for the content or messaging of this post.

Unauthorized reproduction of this article (in part or in whole) is prohibited without the express written permission of Infosec Island and the Infosec Island member that posted this content--this includes using our RSS feed for any purpose other than personal use.