An Android app sold at unofficial Chinese app stores can record phone conversations without the owner's approval and transmit call information to a remote server.
Researchers recently uncovered a new Android app sold in Chinese app
stores that has the capability to surreptitiously record phone
Once installed on the victim's Android device, the app downloads a
"configuration" file containing the parameters for a remote server and
proceeds to record and store phone conversations entirely without the
phone owner's knowledge, Dinesh Venkatesan, a researcher with CA Technologies
wrote in the company blog Aug. 2. The recordings, in AMR format, are
saved onto the device's SD card and can be played back on software such
as VLC Media Player, Venkatesan said.
Researchers have warned eWEEK in the past that voice-recording malware
could be used to capture account passwords, credit card numbers and
social security numbers that consumers may say while talking with
customer service representatives on the phone.
This type of functionality has been seen before in commercial spyware,
Ciaran Bradley, vice president of handset security at Adaptive Mobile,
Venkatesan tested the app in a "controlled environment with two mobile
emulators running simulated Internet services," according to the blog
post. Unlike an Android Trojan that CA Technologies recently analyzed,
which logs the numbers of incoming and outgoing calls and the call
duration into a text file, this app "is more advanced," Venkatesan
Symantec researchers pointed out that while the app may be used for
nefarious purposes, the creator of the app is being quite upfront about
the capabilities. The app, found on unofficial Chinese app stores, is
listed as a way for jealous spouses to monitor their significant
other's phone conversations for hints of infidelity, said Irfan Asrar,
an analyst with Symantec Security Response
It is also not very stealthy because after it is installed on a user
device by someone else, the owner can easily tell by looking at the
screen that a call is being recorded.
While Venkatesan didn't observe it directly, the configuration file
hinted at an ability to upload the recorded calls from the SD card to a
remote server. Symantec's Asrar did not find that to be the case in
Symantec's own analysis, saying that a physical access to the device
was required to retrieve the files. The app did have the ability to
send data such as GPS location and logs to the remote server, which
"the suspicious husband or wife" would have to pay to see a copy of,
This call-recorder needs user intervention, most likely by the spouse
who has commandeered the device, before it can be installed. So there
is a security risk of users having recording software installed without
Intentionally malicious or not, the app definitely has the potential to
be used as a Trojan. Even though it displays a legitimate permissions
screen stating what device capabilities it needs access to, such as
audio recording and outgoing call interception, users rarely think
twice about what the app is capable of doing, according to Bradley.
Despite being PC-security savvy, users tend to consider the mobile
environment "safe" and not think twice about install prompts, links in
instant messages and SMS messages and other threats, Bradley said.
Criminals are betting that the average mobile user will install apps
without thinking twice. "The criminals may very well win this type of
bet," Bradley said.
A recent study from Lookout Security
suggested Android users are 2.5 times more likely to be affected by malware today than they were six months ago.
"As it is already widely acknowledged that this year is the year of
mobile malware, we advise the smartphone users to be more logical and
exercise the basic security principles while surfing and installing any
applications," Venkatesan wrote.