Tracking Mobile Malware Groups at Google

I ran across this opportunity at Google: Analyst, Android Security
https://www.google.com/about/careers/search#!t=jo&jid=66345001&

It piques my interest as one of the stated goals of the job is "[becoming] an expert in the workings of mobile malware campaigns".  A few years ago(2011) I was able to momentarily take a step back from analyzing individual samples to take a look at the state of mobile malware and how criminals and their networks profit.

The 'Mobile App Moolah' presentation was based off a number of years of data we had amassed on malware sources(e.g. geography and authors) as well as intelligence shared between other Antivirus researchers.  My strengths lay in analyzing the samples, identifying characteristics that would hint at possible origins and apparent motives of malware authors.  Other colleagues provided insight on how malware authors and organized crime set up infrastructure(i.e. monetization methods, advertising, acquisition of targets) for  turning what used to be a hobby into profitable enterprises.

How Criminals profit from mobile malware infections

From the collection of metadata I had on in the wild samples I could see how criminals operated in two large geographical regions; for ease of reference, Russian and Chinese speaking regions.  Based off of the code we were seeing the Russian zone employed simpler(though still highly successful) attacks and the Chinese zone using complex and multistage attacks.

I still had only half the picture. I could see the tactics used against victims on their smartphones, but the shared intelligence on crime networks filled in the rest. With Russian SMS sending trojans the profit turned on having easy access to vendors that provided relatively anonymous Premium Rate SMS short codes("Text 'Ring' to 12345 for the latest ringtones"). The ability to acquire a short code quickly and run a campaign(paid for by unaware victims through mobile billing) made it difficult for the perpetrators to get caught while still earning a return on their investment in developing the malware.

The Chinese attacks were complex with anti-evasion and encrypted Command and Control(C&C) channels, due mainly to competition. Competition equally from Security/Antivirus vendors and from rival organized crime. While one could easily steal 1 Yuan from a million victims and net a profit, keeping your enemies from hijacking your mobile botnet still requires a larger R&D investment(e.g. code protection, encryption, etc). The back end, or how the criminals profited also varied. Personally Identifiable Information(PII) and various chat accounts with associated wallets provided alternate streams of income versus Premium Rate SMS fraud.  Organized crime provided multiple service providers to facilitate the passage of virtual funds(QQ coins) to physical/electronic money. Resellers and fences add value to stolen data(social network accounts, credit card numbers).

This Google position appeals as they have access to a significantly larger pool of data on both malware developers and sources for malware. The first step to having victims find your new mobile malware tends to involve Google(i.e. the Play store, Google ads, getting indexed by Google, etc.). Never mind that the Android Security Team receives intelligence, samples and Proof of Concepts from researchers and the public. Whoever eventually gets the role will get some amazing insight into the Android malware underground.
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If one is interested, a video of the 'Mobile Moolah Presentation' and the slides are available. The geographic portion starts at 4:17, the 'How they profit' portion starts at 6:27.

"Android Market Gets a Bouncer to Kick Out Malware"

From McAfee blog:

Today Google announced its Bouncer security service for the Android Market. This is a good initial step in protecting Android users. 

Respect the BouncerTo keep out known troublesome apps, the service performs a malware and spyware scan on all submitted material. It also uses behavioral analysis to determine if a given app is trying to do something suspicious. Google doesn’t stop there; it also does fraud and abuse detection to ban and remove malware writers posing as legitimate developers.

Other ProtectionsAside from Bouncer, Google has older methods of protecting users from bad apps. The company cites its “remote app removal switch,” which allows Google to remotely uninstall apps that violate its policies and or are malicious. Although this is good for handling most basic Android malware, additional measures are sometimes necessary. Sandboxing apps is very useful but is also a double-edged sword. On one side it keeps the average malicious app from accessing user data in other apps; on the other, however, it prevents Google and other security vendors from easily cleaning a device of advanced malware. In the case of malware such as Android/DrdDream or Android/DrddreamLite, which use root exploits to gain total control of a device, it’s necessary to go a step further. These threats that use root exploits completely bypass app sandboxing, requiring stronger methods to remove them. Google now provides a tool that runs on infected devices and removes all malware that were impossible to clean up with the remote removal function.

[...]

Is a ‘Bouncer’ Enough?We haven’t yet seen many details about Bouncer internals, but what we’ve seen so far bodes well for Android security. By itself Bouncer is not enough to clean up all infected devices or to keep all malware out of the market. There will still be a need for further innovation in security software and for defense in depth. The Android security team has a lot of clever people on it and no doubt they will continue to improve security while maintaining Android’s open nature.