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Posts Tagged ‘Sideloading’

Looking Inside a Year of Android Malware

August 14, 2011 2 comments

As you will probably know my Birthday post for Android Malware has deserved a mention from Engadget and Wired. Easily predictable but not for me, the Engadget link has been flooded by comments posted by Android supporters and adversaries, with possible trolls’ infiltrations, up to the point that the editorial staff has decided to disable comments from the article. The effect has been so surprising that someone has also insinuated, among other things, that I have been paid to talk s**t on the Android.

Now let me get some rest from this August Italian Sun and let me try to explain why I decided to celebrate this strange malware birthday for the Android.

First of all I want to make a thing clear: I currently do own an Android Device, and convinced, where possible, all my relatives and friends to jump on the Android. Moreover I do consider the Google platform an inseparable companion for my professional and personal life.

So what’s wrong? If you scroll the malware list you may easily notice that the malware always require an explicit consent from the user, so at first glance the real risk is the extreme trust that users put in their mobile devices which are not considered “simple” phones (even if smart), but real extensions of their personal and professional life.

You might say that this happens also for traditional devices (such as laptops), but in case of mobile devices there is a huge social and cultural difference: users are not aware to bring on their pocket dual (very soon four) cores mini-PCs and are not used to apply the same attention deserved for their old world traditional devices. Their small display size also make these devices particularly vulnerable to phishing (consider for instance the malware Android.GGTracker).

If we focus on technology instead of culture (not limiting the landscape to mobile) it easy to verify that the activity of developing malware (which nowadays is essentially a cybercrime activity) is a trade off between different factors affecting the potential target which include, at least its level of diffusion and its value for the attacker (in a mobile scenario the value corresponds to the value of the information stored on the device). The intrinsic security model of the target is, at least in my opinion, a secondary factor since the effort to overtake it, is simply commensurate with the value of the potential plunder.

What does this mean in simple words? It means that Android devices are growing exponentially in terms of market shares and are increasingly being used also for business. As a consequence there is a greater audience for the attackers, a greater value for the information stored (belonging to the owner’s personal and professional sphere) and consequently the sum of these factors is inevitably attracting Cybercrooks towards this platform.

Have a look to the chart drawing Google OS Market share in the U.S. (ComScore Data) compared with the number of malware samples in this last year (Data pertaining Market Share for June and July are currently not available):

So far the impact of the threats is low, but what makes the Google Platform so prone to malware? For sure not vulnerabilities: everything with a line of code is vulnerable, and, at least for the moment, a recent study from Symantec has found only 18 vulnerabilities for Google OS against 300 found for iOS (please do no question on the different age of the two OSes I only want to show that vulnerabilities are common and in this context Android is comparable with its main competitor).

Going back to the initial question there are at least three factors which make Android different:

  1. The application permission model relies too heavily on the user,
  2. The security policy for the market has proven to be weak,
  3. The platform too easily allows to install applications from untrusted sources with the sideloading feature.

As far as the first point is concerned: some commenters correctly noticed that apps do not install themselves on their own, but need, at least for the first installation, the explicit user consent. Well I wonder: how many “casual users” in your opinion regularly check permissions during application installation? And, even worse, as far as business users are concerned, the likely targets of cybercrime who consider the device as a mere work tool: do you really think that business users check app permission during installation? Of course a serious organization should avoid the associated risks with a firm device management policy before considering a wide deployment of similar devices, most of all among CxOs; but unfortunately we live in an imperfect world and too much often fashion and trends are faster (and stronger) than Security Policies and also make the device to be used principally for other things than its business primary role, hugely increasing risks.

This point is a serious security concern, as a matter of fact many security vendors (in my opinion the security industry is in delay in this context) offer Device Management Solution aimed to complete the native Application Access Control model. Besides it is not a coincidence that some rumors claim that Google is going to modify (enhance) the app permission security process.

As far as the second point is concerned (Android Market security policy), after the DroidDream affair, (and the following fake security update), it is clear that the Android Market Publishing (and Security) model needs to be modified, making it more similar to the App Store. There are several proposals in this context, of course in this place is not my intention to question on them but only to stress that the issue is real.

Last but not least Sideloading is something that makes Android very different from other platforms (read Apple), Apple devices do not allow to install untrusted apps unless you do not Jailbreak the devices. Android simply needs the user to flag an option (By The Way many vendors are opening their Android devices to root or alternate ROMs, consider for instance LG which in Italy does not invalidate the Warranty for rooted devices) or HTC which, on May 27, stated they will no longer have been locking the bootloaders on their devices.

So definitively the three above factors (together with the growing market shares) make Android more appealing for malware developers and this is not due to an intrinsic weakness of the platform rather than a security platform model which is mainly driven by the user and not locked by Manufacturer as it happens in case of Cupertino.

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L’Androide Minacciato Alla Radice

Questa mattina, il buongiorno non ce lo porta l’aroma di caffè e un bel croissant al burro, ma l’ennesima nota di Lookout che segnala l’ennesimo malware per il mai troppo cagionevole Androide. La minaccia viene ancora dall’Estremo Oriente, ed in particolare dalla Cina che si conferma terra ostica per la salute virtuale del Sistema Operativo di Mountain View (mi verrebbe da dire che l’Androide è proprio sensibile alla Cinese).

I sintomi usuali ci sono tutti: il Market Parallelo ed un eseguibile chiamato zHash, che ricalca l’orma del predecessore DroidDream, in grado di rootare (non è una parolaccia ma un improbabile improvvisato neologismo a cui dovremo purtroppo abituarci) il dispositivo mediante il medesimo exploit exploid.

Naturalmente, per non farsi mancare niente, è stata registrata una versione della stessa applicazione anche nel Market Ufficiale, con lo stesso nome, contenente quindi lo stesso exploit, ma priva del codice necessario per invocarlo. Magra consolazione in quanto è sempre meglio non avere il nemico in casa anche se dormiente.

Ad ogni modo l’applicazione, che sembra abbia avuto 5000 download, è stata già rimossa da Google che ha esercitato ancora una volta (sta diventando un’abitudine troppo frequente) la possibilità di disinstallare l’applicazione da remoto (ovviamente la rimozione “coatta” è stata attuata solo per le versioni scaricate dal market ufficiale).

Per inciso la pericolosità del malware sembra relativamente bassa. Ovviamente una volta che il terminale è stato compromesso illecitamente (all’insaputa dell’utente), potrebbe poi essere vittima di altre applicazioni malevole facenti leva sui permessi di root indebitamente acquisiti.

Per ora nessuna altra informazione, rimangono comunque valide le, mai troppo citate, usuali raccomandazioni:

  • Evitare, a meno che non sia strettamente necessario, di abilitare l’opzione di installazione delle applicazioni da Sorgenti Sconosciute (pratica definita anche “sideloading”).
  • Fare attenzione in generale a ciò che si scarica e comunque installare esclusivamente applicazioni da sorgenti fidate (ad esempio l’Android Market ufficiale, le cui applicazioni non sono infette). Buona abitudine è anche quella di verificare il nome dello sviluppatore, le recensioni e i voti degli utenti;
  • Controllare sempre i permessi delle applicazioni durante l’installazione. Naturalmente il buon senso corrisponde al migliore anti-malware per verificare se i permessi sono adeguati allo scopo dell’applicazione;
  • Fare attenzione ai sintomi comportamenti inusuali del telefono (ad esempio strani SMS o una sospetta attività di rete) che potrebbero essere indicatori di una possibile infezione;
  • A questo punto, aimé (e torniamo al tema da poco discusso relativo al costo della sicurezza, valutare una applicazione anti-malware tra le molteplici offertae, destinata oramai a diventare un inseparabile companion.
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