HKCert
Security Blog

Hong Kong Google Play Store's Apps Security Risk Report (June 2015)

Release Date: 26 / 06 / 2015
Last Update: 26 / 06 / 2015

 

Hong Kong Computer Emergency Response Team (HKCERT) Coordination Centre cooperates with the National Computer Network Emergency Response Technical Team of China (CNCERT) for detecting malicious and suspicious behaviors of Apps from the Google Play Store, in order to study the security risk of apps in the Google Play Store in Hong Kong area. CNCERT provides us analyzed result, and we collate the detection result and publish security alerts to the public.

 

In the report of June, we have downloaded 200 apps from Play Store, where 5 apps have been identified as high risk. None of them were removed from Play Store (on or before 24-Jun). The detail of report is shown as follow.

 

Target scope

  • Top 50 Free Applications in Hong Kong area
  • Top 50 New Free Applications in Hong Kong area
  • Top 50 Free Games in Hong Kong area
  • Top 50 New Free Games in Hong Kong area

 

Scanned Apps

  • Successful downloaded and scanned: 200 apps
  • Unable to download via the system: 0 apps
  • Downloaded date: 5-June 2015
  • List of the downloaded apps: "Appendix 1" [download]

 

Analysis Overview

 

In this analysis, 200 apps were scanned for bad behaviors. Based on the level of security threat, the apps were divided into 2 categories: apps with malicious and apps with suspicious behaviors. Malicious behavior refers to apps having malicious purpose explicitly, which could cause direct harm to systems and users' interests. Suspicious behavior refers to apps having behavior, which could cause direct harm to systems and users' interests, but no malicious behavior can be explicitly identified.

 

1. Scanning Result

 

Among the 200 scanned apps, 5 apps were identified as security high risk. These 5 Apps were identified with the following high risk behavior signatures Android.Adware.SmsReg, Android.Youmi, Android.Airpush, etc.

 

List of security high risk apps

 

Application

High risk behavior signature / Ad plug-in

Malware detection ratio by VirusTotal

Status #

1) 快的打车    (v3.8)

Category: Top Free App
Installs: 500,000+
High risk behavior description:
obtain SIM operator name, obtain SIM serial number, obtain SIM status, read phone number, and connect to the Internet.

Android.Adware.SmsReg

10 / 56 [Link]

Available on play store

2) 全民槍戰真人實時對戰FPS射擊競技手遊    (v1.8.1)

Category: Top Free App, New Free App, Top Free Game
Installs: 500,000+
High risk behavior description:
obtain SIM operator name, obtain SIM serial number, obtain SIM status, obtain WiFi configuration, read phone number, and connect to the Internet.

Android.Adware.SmsReg

8 / 56 [Link]

Available on play store

3) Catch mermaid    (v1.5)

Category: New Free App, Top Free Game
Installs: 100,000+
High risk behavior description:
obtain SIM operator name, obtain SIM serial number, obtain SIM status, read phone number, and connect to the Internet.

Android.Youmi

17 / 55 [Link]

Available on play store

4) Angels Revenge HD    (v1.1)

Category: Top Free App, New Free App, Top Free Game
Installs: 100,000+
High risk behavior description:
obtain SIM operator name, obtain SIM serial number, obtain SIM status, obtain device information, read phone number, connect to the Internet, and send out phone information.

Android.Airpush

10 / 56 [Link]

Available on play store

5) FishingAge    (v1.3.3)

Category: Top Free Game
Installs: 100,000+
High risk behavior description:
obtain SIM operator name, obtain SIM serial number, obtain SIM status, read phone number, connect to the Internet, and send out phone information.

Android.Youmi

18 / 56 [Link]

Available on play store

 

Remark (#): The status was checked on 24-Jun. There is no direct relation between the on-shelf status and this report.

 

 

2. High risk behavior signature and Ad plug-in

 

High risk behavior signature and Ad plug-in

High risk behavior

Android.Adware.SmsReg

It is a high risk app. When the app is running, it can receive user's SMS and send SMS in the background. It can cause user information disclosure  and pay additional charge.

Android.AirPush

This is an advertisement framework. It can aggressively push ad to device's notification bar. It can modify browser's bookmark, and remove icon on the main screen. The ads will ask for money. Some ads showed in the notification bar will lure user to subscribe and pay for SMS service. Three common luring ads are 1) fake shop, 2) fake free call service, 3) system notification impersonation

Android.Youmi

This is advertisement software bundled with the application, which can insert advertisement in the app, download and install new app, steal user's private information , such as geo-location, phone serial number, etc.

 
 
3. High risk app analysis
 
Please refer to "Appendix 2" [download]