Preventing App from detecting blacklisted App's Folder

[n4hom-01]

Hey, is it possible to add a feature preventing apps from discovering blacklisted app's app folder or any folder related to it. I discovered some apps that scans Android/data folder to detect target apps.

[yueryang]

This is very useful, but can be very difficult currently. The detectors can directly check the existence of the directories without root permissions on some occasions. For example, when using cd to cd to those directories after switching to the parent directories of them, it will show Permission Denied instead of No such file or directory, or even succeed. Also, using -e or stat is feasible. In these cases, the directories are found.

Taking com.topjohnwu.magisk and io.github.vvb2060.magisk as an example, we can use a shell to check the existence of the non-customized directories without root permissions.

#!/system/bin/sh
folders="/data/data /data/user/0 /data/user_de/0 /sdcard/Android/data"
packageNames="com.topjohnwu.magisk io.github.vvb2060.magisk"
for packageName in ${packageNames}
do
	for folder in ${folders}
	do
		if [[ -e "${folder}/${packageName}" ]];
		then
			echo "Found \"${folder}/${packageName}\". "
		fi
	done
done
exit 0

Additionally, some Xposed plugins like WechatXposed will directly store files in /sdcard, which needs to be hidden. These customized directories need to be specified manually for future HMA/HAML. If HMA/HMAL wants to prevent such detection, that is, to block specific files or folders by the blacklisted applications, it needs to hook syscall, which is very difficult so far. Just see if future KPM or other implementations can support this.

Additionally, on Android 12 and above, the detection of an APP by judging the specified folders will become meaningless. However, on Android 11 and below, it is still possible to detect APPs in such a way. To enable the isolation on Android 11 and below, like Android 12 and above, you can try to modify /etc/compatconfig/services-platform-compat-config.xml by replacing enableAfterTargetSdk="29" id="143937733" with enableAfterTargetSdk="0" id="143937733". This can prevent the non-customized directories of the installed applications from being detected by other applications.

PS: I am not the author of HMA/HMAL.

Thanks & Regards.

[Morrigan-Ship]

Wow, please add this feature