The amount of malware aimed at infecting Android devices worldwide more than doubled last year, according to a new report from a mobile-security firm.
The sheer number of pieces of malware for the Android platform rose from less than 25,000 in 2011 to more than 65,000 in 2012.
The annual report, published by mobile security company NQ Mobile, also estimated that nearly 33 million devices were infected in 2012, up from just under 11 million the year before — an increase of more than 200 percent.
The bulk of the Android infections — 25.5 percent — occurred in China, followed by India with 19.4 percent and Russia with 18 percent.
The United States accounted for less than 10 percent of the world's Android infections. The report noted that the Android infection rate in the U.S. was essentially unchanged from 2011 to 2012.
NQ Mobile said the most popular way of infecting Android devices was through app repackaging, which involves taking popular apps from the official Google Play store, adding malicious code and then uploading the corrupted app onto an unofficial app market.
Middle Kingdom malware
Infections often occur when Android users download cut-rate apps from unofficial markets to avoid paying full price, the NQ report noted.
In China, Google Play does not sell paid apps, thanks to the company's opposition to Chinese government privacy policies, and most users must "sideload" apps from dozens of unofficial app stores.
Ironically, malware hidden in corrupted apps usually steals victims' personal data. For non-Chinese users, the risks and headaches involved with getting apps from unofficial sources often outweigh the benefits, but tens of millions of Chinese Android users don't have a choice.
Even legitimate Chinese Android apps are vulnerable to malware. A recent study by four Chinese researchers working at the University of California, Davis, found that Chinese-language social-networking apps often had sloppy coding practices that could easily be exploited by malware.
In March, a Chinese government study found that two-thirds of Chinese-language Android apps were reading users' private data, including locations, address books and text and calling logs.
One-third of all the apps were reading user data that had no discernible connection to the apps' stated purposes, and about 15 percent were making calls and sending texts without the user's knowledge. [See also: 10 Tips to Keep Your Android Phone Safe ]
Untrustworthy URLs, sinister smishes
Cybercriminals also steal Android users' personal data through malicious websites. Subtle changes in URLs can redirect users to nefarious clones of the sites they think they're accessing.
On the malicious sites, users are often prompted to populate a form field with a combination of personal information, including names, email addresses, passwords and more, or to download a piece of malicious software.
Mobile cyberthieves also use a technique called "smishing," a combination of "SMS" and "phishing." It involves sending an unsolicited text message, or SMS, to a target and persuading the target to click a link in the message, which in turns downloads and installs a malicious Android app.
Some of the apps, especially in Russia and other parts of Eastern Europe, clandestinely access premium text-message services that can cause a victim's phone bill to skyrocket.
Android users can avoid becoming victims of malware and fraud by being very careful about clicking on links and installing apps.
Access the Internet on your Android device with the same level of seriousness you would on a Windows PC. If an email message seems sketchy, don't open the links or attachments it contains. If any link in your email or browser seems suspect, stay away.
By that same token, make sure you're really on the webpage you seek before giving up your password or your personal information. Small screens may make it harder to see a website's full URL, but in the end, taking a moment to check could be a huge timesaver.
TechNewsDaily recommends that users download apps only from the Google Play store, which puts them through a vetting process. Apps on most third-party sites are not screened and could contain very nasty code.
Android users outside of China should also go into the Security sections of their Settings menus and make sure "Unknown sources" is unchecked. That will prevent most Android drive-by downloads of unwanted software from the Internet.
Users of Android 4.2 Jelly Bean should check "Verify apps," which will run downloaded apps through a screening process before installing them. (Sadly, NQ Mobile noted that nearly 40 percent of Android phones still run the 2-year-old 2.3 Gingerbread version, which has fewer security features.)
Finally, read up on the different brands of Android anti-virus software, some of which cost nothing, and install one. Make sure to keep it updated with the latest malware definitions.