Virus (or Trojan) in Android

Question

Definition of virus is (from Wikipedia):

A computer virus is a malware program that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected"

And the main difference with Trojan is that virus can replicates itself by inserting copies of itself.

Thus, if we assume that after user installs it, the application does malicious activities without interaction with user in a unrooted Android system:

• Should it be classified as virus or as trojan?
• When should such malware classified as virus or trojan?
• Is it possible to create a virus according to this definition in unrooted Android system?

Answer 1

• If the app's malicious payload copies itself to other apps or documents on the device, it is a virus.
• If the app spreads itself to other devices, but does not do so by "infecting" legitimate apps or documents, it is a worm
• If the app relies on a human to install it, and then does some nasty stuff besides simply replicating itself, it is a trojan

Since Android apps are signed, it should probably be a little trickier to create a virus (though not a worm or trojan). Of course if the user enables "unknown sources", this won't help.

Answer 2

Is there really such a thing as an Android virus?

Historically carried over from the old PC world, a “virus” is a program that replicates itself by attaching to another program. Hackers often used this method to spread their nefarious work, and virus became a popular term to refer to all types of malicious software (malware) on computers. In the case of smartphones, to date we have not seen malware that replicate itself like a PC virus can, and specifically on Android this does not exist, so technically there are no Android viruses. However, there are many other types of Android malware. Most people think of any malicious software as a virus, even though it is technically inaccurate.

So what is Android malware?

Malware, short for malicious software, is software designed to secretly control a device, steal private information or money from the device’s owner. Malware has been used to steal passwords and account numbers from mobile phones, put false charges on user accounts and even track a user’s location and activity without their knowledge. Learn about some of the most notable malware Lookout has blocked in Resources/Top Threats.