Kaspersky Lab has discovered a sophisticated Windows-like Android Trojan that has found enough new vulnerabilities in Google’s operating system to make itself both invisible and extremely difficult to de-install.
Dubbed Backdoor.AndroidOS.Obad.a by Kaspersky’s researchers, it is the sort of malware that will give Google’s security team a few sleepless nights.
The anxiety won't be that many Android users are likely to be attacked by it – Kaspersky said it was as rare as 0.15 percent of mobile malware infections detected by the firm in one three-day period – but for what it implies about the evolving capabilities of Android threats.
The program uncovered by Kaspersky is multi-facteted, ostensibly another premium rate SMS fraud tool but is also capable of downloading further capabilities as it pleases.
Its basic tactic is to hide whilst blocking the efforts of anyone trying to investigate what it’s up to.
On installation (presumably hidden inside a legitimate-looking app) it asks for Device Administrator privileges. If granted, it exploits a previously unknown flaw in Android to 'disappear' itself from the list of apps that have such privileges, making it a major challenge to remove without resorting to root.
A second vulnerability it uses is in the AndroidManifest.xml file used to define an app's structure and parameters, which it modifies to obscure its behaviour should security researchers try to analyse it.
It further exploits an error in DEX2JAR which makes it harder for researchers to convert APK (Android app package) files into Java Archive (JAR) format and so stymying forensics.
Finally, it tries to spread itself via Bluetooth should any other Android phone making a direct connection as well as sending back extensive information on the phone’s state to its command and control servers on the Internet.
“Backdoor.AndroidOS.Obad.a looks closer to Windows malware than to other Android Trojans, in terms of its complexity and the number of unpublished vulnerabilities it exploits. This means that the complexity of Android malware programs is growing rapidly alongside their numbers,” concluded Kaspersky’s Roman Unuchek in a blog.
The malware’s other interesting feature was its determination to block analysis through its extensive use of encryption to hide its command and control communication, he said.
There is plenty of evidence that there is now more Android malware, almost to the total exclusion of all other platforms, even if much of it remains geographically isolated and relatively unsophisticated. So far there are just fewer ways to make money although that could change as mobile banking expands.
Obad.a is a sign that criminals are advanced in looking for an finding holes in Android’s rather thin security carapace. Android is no Windows XP when it comes to the ease with which it and its apps can be undermined but the rise of more complex malware variants in a still-fragmented environment should be a worry.
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