Fake Flash tries to phish big 4 Oz bank Android customers and snatch their SMS

Online crooks have served up a special serve of Android banking malware designed to dupe customers of Australia’s big four banks to divulge SMS two-factor authentication codes.

As security experts have long warned, it’s a bad idea for Android users to install apps from anywhere but Google Play, even though they have the option to. New malware targeting Australian online banking customers is a reminder why that’s solid advice.

Security firm ESET has warned that a relatively new threat, which it calls Android/Spy.Agent.SI, has been customised to target customers of Westpac, ANZ, Commbank, and NAB, as well as their New Zealand subsidiaries. The malware also targets credentials for banks in Turkey, one US bank, PayPal and Google.

The Android malware is essentially the same for all targets, but criminals have customised a lock screen to look like the legitimate login pages for each of these banks’ mobile apps.

“If a target application is launched, the malware is triggered and a fake login screen overlays the original mobile banking one, with no option to close it,” ESET notes in its writeup on the Android malware.

The lock screen is an attempt to force victims to provide their banking credentials by preventing them from exiting the fake login page until the credentials are provided.

The malware will also monitor for and capture incoming SMS and re-route it to a server under the attacker’s control. ESET notes that the malware will also remove records of the SMS from the device, likely to avoid raising suspicion.

Australian banks typically don’t require anything more than a customer ID and password to login to an account, however once logged certain transactions — such as international transfers — require authorisation, which is done using a 6-digit code delivered by SMS.

So, with the victim’s credentials already on hand, the attacker could login to the target’s online account, say from a desktop in Eastern Europe, initiate an international transfer and then wait for the SMS code to be sent to the infected Android device.

The good news is that the malware is not being distributed on Google Play. Instead, victims would need to install a file that purports to be Adobe’s Flash Player media player.

One note here is that Adobe stopped making the real Flash Player for Android a few years ago, so any Android users that do come across a Flash Player update should definitely avoid it. The most recent version of Flash Player for Android supported Android 4.0 Ice Cream Sandwich, released in 2011.

CSO Australia has asked ESET for any details on the number of infections in Australia, however the company’s “prevalence map” for the malware suggests it is not widespread.

ESET also doesn’t say which sites users are being directed from to install the fake Flash Player update, for example, a torrent site that requires Flash Player to view the content.