#2: Your call or message history includes some unknown entries
Regularly checking your call history for unknown numbers is an excellent habit to adopt. Lots of malware families try to make calls or send messages to premium international numbers. Such malware ends up having a direct impact on the user, who unjustly has to pay the costs.
This type of malware has been growing significantly and about 50 new examples are detected each month. Our products identify this type of malware under the Android/TrojanSMS family. If we analyse the number of new variants of this family that have been created since the start of this year, we can see the extent of this family's growth. Unfortunately, our research suggests that this trend shows no sign of decreasing in the near future.
#3: Excessive data usage
Malicious apps may be using the data system to communicate with command and control centers operated by cybercriminals in order to download orders and updates, as well as send back information stolen from the device.
If you usually check how much data your apps use, you will quickly become aware of any changes to the normal pattern. While checking data usage of an app be sure to also check the times when the sending and receipt of data is highest and compare this with your use of the device. If there is an excessive amount of data exchange taking place at times when you don't use the device, you have grounds for suspecting that something strange is going on.
#4: You or your contacts receive strange text messages
One method used a lot by cybercriminals to control infected mobile devices is sending text messages containing commands to be interpreted by the malware, which then takes the corresponding action. Lots of examples of malware manipulate message logs to delete any such messages that could raise the user's suspicions, but others don't bother with such precautionary measures, in which case the user can read the content that is received and sent.
Mobile malware can also send text messages to phone numbers from the user's list of contacts as a way to propagate itself, using this method to get the recipients to download malicious content via specific links. If your friends receive strange messages from your phone, you should check what apps are installed on it.
#5: Your payment breakdown includes actions you did not make
Sending text messages, making calls, and using the data system will result in increased costs, which the user will be responsible for. Examining the costs attributed to your mobile phone number on a monthly basis is a good practice to be able to detect any malicious activity quickly.
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