Social Network Account Stealers Hidden in Android Gaming Hacking Tool

Authored by: Wenfeng Yu

McAfee Mobile Research team recently discovered a new piece of malware that specifically steals Google, Facebook, Twitter, Telegram and PUBG game accounts. This malware hides in a game assistant tool called “DesiEsp” which is an assistant tool for PUBG game available on GitHub. Basically, cyber criminals added their own malicious code based on this DesiEsp open-source tool and published it on Telegram. PUBG game users are the main targets of this Android malware in all regions around the world but most infections are reported from the United States, India, and Saudi Arabia.

What is an ESP hack?

ESP Hacks, (short for Extra-Sensory Perception) are a type of hack that displays player information such as HP (Health Points), Name, Rank, Gun etc. It is like a permanent tuned-up KDR/HP Vision. ESP Hacks are not a single hack, but a whole category of hacks that function similarly and are often used together to make them more effective.

How can you be affected by this malware?

After investigation, it was found that this malware was spread in the channels related to PUBG game on the Telegram platform. Fortunately, this malware has not been found on Google Play.

Figure 1. Re-packaged hacking tool distributed in Telegram

Main dropper behavior

This malware will ask the user to allow superuser permission after running:

Figure 2. Initial malware requesting root access.

If the user denies superuser request the malware will say that the application may not work:

Figure 3. Error message when root access is not provided

When it gains root permission, it will start two malicious actions. First, it will steal accounts by accessing the system account database and application database.

Figure 4. Get google account from android system account database. — Figure 4. Get a Google account from the Android system account database.

Second, it will install an additional payload with package name “com.android.google.gsf.policy_sidecar_aps” using the “pm install” command. The payload package will be in the assets folder, and it will disguise the file name as “*.crt” or “*.mph”.

Figure 5. Payload disguised as a certificate file (crt extension)

Stealing social and gaming accounts

The dropped payload will not display icons and it operates directly on the screen of the user’s device. In the apps list of the system settings, it usually disguises the package name as something like “com.google.android.gsf” to make users think it is a system service of Google. It runs in the background in the way of Accessibility Service. Accessibility Service is an auxiliary function provided by the Android system to help people with physical disabilities use mobile apps. It will connect to other apps like a plug-in and can it access the Activity, View, and other resources of the connected app.

The malware will first try to get root permissions and IMEI (International Mobile Equipment Identity) code that later access the system account database. Of course, even if it does not have root access, it still has other ways to steal account information. Finally, it also will try to activate the device-admin to difficult its removal.

Methods to steal account information

The first method to steal account credentials that this malware uses is to monitor the login window and account input box text of the stolen app through the AccessibilityService interface to steal account information. The target apps include Facebook (com.facebook.kakana), Twitter (com.twitter.android), Google (com.google.android.gms) and PUBG MOBILE game (com.tencent.ig)

The second method is to steal account information (including account number, password, key, and token) by accessing the account database of the system, the user config file, and the database of the monitored app. This part of the malicious code is the same as the parent sample above:

Figure 6. Malware accessing Facebook account information using root privileges

Finally, the malware will report the stolen account information to the hacker’s server via HTTP.

Gaming users infected worldwide

PUBG games are popular all over the world, and users who use PUBG game assistant tools exist in all regions of the world. According to McAfee telemetry data, this malware and its variants affect a wide range of countries including the United States, India, and Saudi Arabia:

Figure 7. Top affected countries include USA, India and Saudi Arabia — Figure 7. Top affected countries include USA, India , and Saudi Arabia

Conclusion

The online game market is revitalizing as represented by e-sports. We can play games anywhere in various environments such as mobiles, tablets, and PCs (personal computers). Some users will be looking for cheat tools and hacking techniques to play the game in a slightly advantageous way. Cheat tools are inevitably hosted on suspicious websites by their nature, and users looking for cheat tools must step into the suspicious websites. Attackers are also aware of the desires of such users and use these cheat tools to attack them.

This malware is still constantly producing variants that use several ways to counter the detection of anti-virus software including packing, code obfuscation, and strings encryption, allowing itself to infect more game users.

McAfee Mobile Security detects this threat as Android/Stealer and protects you from this malware attack. Use security software on your device. Game users should think twice before downloading and installing cheat tools, especially when they request Superuser or accessibility service permissions.