Develop Reference

Sniffing a LAN : Jpcap java program only seems to catch my packets

I have to create a program that sniff a local network for school. I chose to work with Java and found out that you can capture packets with jpcap.
So I wanted to follow one of the example provided in jpcap's github and it seems like I can only find my own packets.
Like I said, I've looked at the code and chose my wifi interface. The program is capturing packets and I put all the source ip addresses in a text file to run some tests. I have also created a hashmap the ip addresses I've finded when I did a arp -a. From what I've read online, this command shows you ip addresses in your network.I created a boolean set to false and I then proceeded to run a loop that goes through the textfile and looked if the ip address was in the hashMap : if one of the addresses appeared in the hashmap, the boolean would be change to true and it would mean that I've managed to catch something.
After running the test, the boolean came out false.
Here's the example code
``public class PacketCaptor {
private static final int INFINITE = -1;
private static final int PACKET_COUNT = INFINITE;
/*
private static final String HOST = "203.239.110.20";
private static final String FILTER =
"host " + HOST + " and proto TCP and port 23";
*/
private static final String FILTER =
// "port 23";
"";
public static void main(String[] args) {
try {
if(args.length == 1){
PacketCaptor sniffer = new PacketCaptor(args[0]);
} else {
System.out.println("Usage: java Sniffer [device name]");
System.out.println("Available network devices on your machine:");
String[] devs = PacketCapture.lookupDevices();
for(int i = 0; i < devs.length ; i++)
System.out.println("\t" + devs[i]);
}
} catch(Exception e) {
e.printStackTrace();
}
}
public PacketCaptor(String device) throws Exception {
// Initialize jpcap
PacketCapture pcap = new PacketCapture();
System.out.println("Using device '" + device + "'");
pcap.open(device, true);
//pcap.setFilter(FILTER, true);
pcap.addPacketListener(new PacketHandler());
System.out.println("Capturing packets...");
pcap.capture(PACKET_COUNT);
}
}
class PacketHandler implements PacketListener
{
WritingClass writing = new WritingClass();
public void packetArrived(Packet packet) {
try {
// only handle TCP packets
if(packet instanceof TCPPacket) {
TCPPacket tcpPacket = (TCPPacket)packet;
byte[] data = tcpPacket.getTCPData();
String srcHost = tcpPacket.getSourceAddress();
String dstHost = tcpPacket.getDestinationAddress();
String isoData = new String(data, "ISO-8859-1");
System.out.println(srcHost+" -> " + dstHost + ": " + isoData);
String datas = srcHost+"|"+dstHost+"|";
writing.write(datas, this.writing.getFileName());
}
} catch( Exception e ) {
e.printStackTrace();
}
}
Can anyone help me figure out why It doesn't work ?
Thank you so much for your help

The reason why you aren't able to capture more packets is because you need an interface in promisc or raw mode, I advice you to use a proper sniffer like wireshark to check if other packets that aren't addressed to you can be captured. If not, means you need apply a mitm method because you are in a commuted network. For use that code on wifi should be enough an interface in monitor mode (check aircrack-ng suite).
In GNU/Linux Debian based systems may use the command iw dev wlan0 interface add mon0 type monitor (from package wireless-tools)

Start user's standard mail client with attachment pre-attached

I'm looking for a way that my application can call the user's standard mail application (e.g. Outlook, Thunderbird, etc.). And give it an recipient address, the email text and an attachment.
So, basically the standard email application should pop up have the email ready for me (with recipient, text and attachment) and all that is left to do for me is pressing "send" in my outlook, thunderbird etc.
I've been googling for a while now, but I couldn't find a real solution.
I've been looking into mapi a bit but it seems like 1. it's deprecated and 2. it's mainly built for outlook.
Any help/suggestions/solutions greatly appreciated!
Edit: I have seen the question Start Mail-Client with Attachment but no working answer was provided there and also the question is more than 3 years old.
Edit: Other languages would be ok, too. Has to work on Windows XP, Vista, 7, 8 (both 32 and 64 bit)
UPDATE: It seems to be more difficult than I have thought it to be.
I've been looking into JMAPI, which apparently only works for 32bit Systems.
I've also seen the solutions on codeproject.org (here and here), but I somehow couldn't get them to work.
Now I'm trying to do it with command line:
1. Read user's default mail client
2. Call a batch file according to the email client. (Yes you have to write a batch file for every common mail client.
Example for outlook:
"outlook.exe" /a "F:\test.png" /m "test.test#test.test&cc=test#test.test&subject=subject123&body=Hello, how are you%%3F%%0D%%0Anew line"
--> see my provided answer for futher info on that method

So...
After days of research I gave up to get a general solution.
I came up with a solution working at least for the two most common clients (Thunderbird & Outlook)
My solution is basically calling the application from command line.
For those interested, here is my solution: (I haven't tested it cross platform - works on my old XP laptop though)
import java.io.IOException;
/*
:: Punctuation Hexadecimal equivalent
:: ----------------------------------------------
:: Space ( ) %20
:: Comma (,) %2C
:: Question mark (?) %3F
:: Period (.) %2E
:: Exclamation point (!) %21
:: Colon (:) %3A
:: Semicolon (;) %3B
:: Line feed %0A --> New line %0D%0A
:: Line break (ENTER key) %0D --> New line %0D%0A
*/
public class Main {
static String test = "hi";
private static String attachment;
private static String to;
private static String cc;
private static String subject;
private static String body;
public static void main (String[] args){
attachment = "F:\\pietquest.png";
to = "test#test.de";
cc = "a.b#c.de";
subject = "TestSubject 123";
body = "Hi, what\'s going on%0D%0Anew line";
body = replace(body);
subject = replace(subject);
String[] value = WindowsRegistry.readRegistry("HKEY_LOCAL_MACHINE\\SOFTWARE\\Clients\\Mail", "");
if (value[10].contains("Thunderbird")){
System.out.println("Thunderbird");
String[] pfad = WindowsRegistry.readRegistry("HKEY_LOCAL_MACHINE\\SOFTWARE\\Clients\\Mail\\Mozilla Thunderbird\\shell\\open\\command", "");
String Pfad = pfad[10] + " " + pfad[11];
String argument = Pfad + " /compose \"to=" + to + ",cc=" + cc + ",subject=" + subject + ",body=" + body + ",attachment=" + attachment + "\"";
// System.out.println(argument);
try {
Runtime.getRuntime().exec(argument);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else if (value[10].contains("Outlook")){
System.out.println("Outlook");
String[] pfad = WindowsRegistry.readRegistry(
"HKEY_LOCAL_MACHINE\\SOFTWARE\\Clients\\Mail\\Microsoft Outlook\\shell\\open\\command", "");
String Pfad = pfad[10];
String argument = Pfad + " /a " + attachment + " /m \"" + to
+ "&cc=" + cc + "&subject=" + subject + "&body=" + body + "\"";
// System.out.println(argument);
try {
Runtime.getRuntime().exec(argument);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static String replace(String toReplace){
toReplace = toReplace.replace(" ", "%20");
toReplace = toReplace.replace(",", "%2C");
toReplace = toReplace.replace("?", "%3F");
toReplace = toReplace.replace(".", "%2E");
toReplace = toReplace.replace("!", "%21");
toReplace = toReplace.replace(":", "%3A");
toReplace = toReplace.replace(";", "%3B");
return toReplace;
}
}
and this is the Windows Registry Class: (got that from here)
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
public class WindowsRegistry {
/**
*
* #param location path in the registry
* #param key registry key
* #return registry value or null if not found
*/
public static final String[] readRegistry(String location, String key){
try {
// Run reg query, then read output with StreamReader (internal class)
Process process = Runtime.getRuntime().exec("reg query " +
'"'+ location);
StreamReader reader = new StreamReader(process.getInputStream());
reader.start();
process.waitFor();
reader.join();
// Parse out the value
String[] parsed = reader.getResult().split("\\s+");
if (parsed.length > 1) {
return parsed;
}
} catch (Exception e) {}
return null;
}
static class StreamReader extends Thread {
private InputStream is;
private StringWriter sw= new StringWriter();
public StreamReader(InputStream is) {
this.is = is;
}
public void run() {
try {
int c;
while ((c = is.read()) != -1)
sw.write(c);
} catch (IOException e) {
}
}
public String getResult() {
return sw.toString();
}
}

you can use C#: Example C# or java: Example Java
EDIT
You can use Boost for ssl and send email via smtp

Using java.util.Scanner to print out Scheme Host and Path

So I am supposed to Write a program that reads a URI, for example http://www.cs.unca.edu/csci202, contained on the first input line.
And if an exception is raised by the constructor, the program should print a message giving some information about that problem. And if no exception is raised, the program should print the scheme, host and path of the URI using the appropriate methods of the URI. And if any of these URI properties is missing, it should not be printed. I am supposed to use the scanner to be able to type in the URI and then have it print out the scheme Host Path or error message. So far nothing I have tried has worked. Here is what I have so far:
import java.net.URI;
public class Home04 {
public static void main(String[] args) {
try {
URI uri1 = new URI("");
if (uri1.getScheme() != null) {
System.out.println("Sceme:" + uri1.getScheme() );
}
if (uri1.getHost() !=null){
System.out.println("Host:" + uri1.getHost() );
}
if (uri1.getPath() != null){
System.out.println("Path:" + uri1.getPath() );
}
} catch (Exception e) {
System.out.println("Exception" + e);
}
}
}

Your parsing code is correct.
What you need to do is use below to get input from user
Scanner scanner = new Scanner(System.in);
URI uri1 = new URI(scanner.next());

How to call a class that accepts command line arguments?

I am not a good programmer. In school, I learned MATLAB. So i have no idea what I am doing.
I am working with the ThingMagic M6 reader. They have their own API. I wanted to create my own application to read the program. I want to use a sample program that they have supplied (since my program doesn't seem to work). However, the supplied program only accepts command line arguments. How do i change it so I can pass arguments to it in my code.
This is the supplied code: (at the command line I input tmr://10.0.0.101)
/**
* Sample program that reads tags for a fixed period of time (500ms)
* and prints the tags found.
*/
// Import the API
package samples;
import com.thingmagic.*;
public class read
{
static void usage()
{
System.out.printf("Usage: demo reader-uri <command> [args]\n" +
" (URI: 'tmr:///COM1' or 'tmr://astra-2100d3/' " +
"or 'tmr:///dev/ttyS0')\n\n" +
"Available commands:\n");
System.exit(1);
}
public static void setTrace(Reader r, String args[])
{
if (args[0].toLowerCase().equals("on"))
{
r.addTransportListener(r.simpleTransportListener);
}
}
static class TagReadListener implements ReadListener
{
public void tagRead(Reader r, TagReadData t) {
System.out.println("Tag Read " + t);
}
}
public static void main(String argv[])
{
System.out.println(argv.getClass().toString());
// Program setup
TagFilter target;
Reader r;
int nextarg;
boolean trace;
r = null;
target = null;
trace = false;
nextarg = 0;
if (argv.length < 1)
usage();
if (argv[nextarg].equals("-v"))
{
trace = true;
nextarg++;
System.out.println("Trace");
}
// Create Reader object, connecting to physical device
try
{
TagReadData[] tagReads;
r = Reader.create(argv[nextarg]);
if (trace)
{
setTrace(r, new String[] {"on"});
}
r.connect();
if (Reader.Region.UNSPEC == (Reader.Region)r.paramGet("/reader/region/id"))
{
r.paramSet("/reader/region/id", Reader.Region.NA);
}
r.addReadListener(new TagReadListener() );
// Read tags
tagReads = r.read(500);
// Print tag reads
for (TagReadData tr : tagReads)
System.out.println(tr.toString());
// Shut down reader
r.destroy();
}
catch (ReaderException re)
{
System.out.println("Reader Exception : " + re.getMessage());
}
catch (Exception re)
{
System.out.println("Exception : " + re.getMessage());
}
}
}
This is me trying to use it: (arg comes from a JTextField)
String[] argv = new String[1];
argv[0] = arg;
readOnceApp(argv);
I have a feeling there is a really simple answer to this problem, I just can't figure it out. I searched the internet for a few days and read books, and still can't figure it out. Any help is appreciated. Thank You.
edit: readOnceApp is one method I wrote. It is basically just the main method of the supplied code. I can include it, if it will help. I just didn't want to post too much code.

If you want to call the "main" method of a class from another class, do it like this:
String [] args = new String [1];
args[0]= "some param";
readOnceApp.main(args);
This is making the assumption that "readOnceApp" is the name of your class. (BTW, you should follow the convention of using capitalized class names, e.g. ReadOnceApp).
Hope this helps.

Writing Standard Input and waiting for Standard Output

I'm trying to create a Thread that keeps netsh windows command-line tool open so I can execute netsh commands without open it every single time.
The thing is, once I've created the Thread, just the first command call works... the subsequent calls seems to have no effect.
Here is my code:
public class NetshThread implements Runnable{
private static Process netshProcess = null;
private static BufferedInputStream netshInStream = null;
private static BufferedOutputStream netshOutStream = null;
public BufferedReader inPipe = null;
public void run(){
startNetsh();
}
public void startNetsh(){
try {
netshProcess = Runtime.getRuntime().exec("netsh");
netshInStream = new BufferedInputStream(netshProcess.getInputStream());
netshOutStream = new BufferedOutputStream(netshProcess.getOutputStream());
inPipe = new BufferedReader(new InputStreamReader(netshInStream));
} catch (IOException e) {
e.printStackTrace();
}
}
public void executeCommand(String command){
System.out.println("Executing: " + command);
try {
String str = "";
netshOutStream.write(command.getBytes());
netshOutStream.close();
while ((str = inPipe.readLine()) != null) {
System.out.println(str);
}
} catch (IOException e) {
e.printStackTrace();
}
}
public void closeNetsh(){
executeCommand("exit");
}
public static void main(String[] args){
NetshThread nthread = new NetshThread();
nthread.run();
String command = "int ip set address " +
"\"Local Area Connection 6\" static .69.69.69 255.255.255.0";
nthread.executeCommand(command);
command = "int ip set address " +
"\"Local Area Connection 6\" static 69.69.69.69 255.255.255.0";
nthread.executeCommand(command);
System.out.println("*** DONE ***");
}
}
Thank you!!! =)
Update 1:
Ok... I'm now using a PrintWriter instead... so I think I don't need to flush anything anymore, since the constructor is:
new PrintWriter(netshOutStream, true); (just like Mr. Shiny told me)...
Suppose I decide to break the while loop when the first output line is available... I doesn't work either... the next command wont be executed.... My code now looks like:
import java.io.*;
public class NetshThread implements Runnable{
private static Process netshProcess = null;
private static BufferedInputStream netshInStream = null;
private static BufferedOutputStream netshOutStream = null;
public BufferedReader inPipe = null;
private PrintWriter netshWriter = null;
public void run(){
startNetsh();
}
public void startNetsh(){
try {
netshProcess = Runtime.getRuntime().exec("netsh");
netshInStream = new BufferedInputStream(netshProcess.getInputStream());
netshOutStream = new BufferedOutputStream(netshProcess.getOutputStream());
netshWriter = new PrintWriter(netshOutStream, true);
inPipe = new BufferedReader(new InputStreamReader(netshInStream));
} catch (IOException e) {
e.printStackTrace();
}
}
public void executeCommand(String command){
System.out.println("Executing: " + command);
try {
String str = "";
netshWriter.println(command);
while ((str = inPipe.readLine()) != null) {
System.out.println(str);
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
public void closeNetsh(){
executeCommand("exit");
}
public static void main(String[] args){
NetshThread nthread = new NetshThread();
Thread xs = new Thread(nthread);
xs.run();
String command = "int ip set address " +
"\"Local Area Connection 6\" static .69.69.69 255.255.255.0";
nthread.executeCommand(command);
command = "int ip set address " +
"\"Local Area Connection 6\" static 69.69.69.69 255.255.255.0";
nthread.executeCommand(command);
System.out.println("*** DONE ***");
}
}
and the output I get:
Executing: int ip set address "Local
Area Connection 6" static .69.69.69
255.255.255.0 netsh>.69.69.69 is not an acceptable value for addr.
Executing: int ip set address "Local
Area Connection 6" static 69.69.69.69
Why the second command is not executed???
255.255.255.0
* DONE *
Update 2:
Everything seemed to work just fine until a teacher tried my app in a spanish-windows enviroment....
my code looks like this:
Scanner fi = new Scanner(netshProcess.getInputStream());
public void executeCommand(String command) {
System.out.println("Executing: " + command);
String str = "";
netshWriter.println(command);
fi.skip("\\s*");
str = fi.nextLine();
System.out.println(str);
}
and what i need is to somehow set the netshWriter encoding to the windows default.
Can anyone know who to do this?

You are closing the output stream.

You need to move the stream processing into separate threads. What's happening is that inPipe.readLine() is blocking waiting for netsh to return data. Apache has a package that deals with process handling. I'd look at using that instead of rolling your own (http://commons.apache.org/exec/)

This seems wrong in many ways.
First, why a Runnable object? This isn't ever passed to a Thread anywhere. The only thread you're creating isn't a java thread, it is an OS process created by exec().
Second, you need a way to know when netsh is done. Your loop that reads the output of netsh will just run forever because readLine will only return null when netsh closes its standard out (which is never, in your case). You need to look for some standard thing that netsh prints when it is done processing your request.
And as others mentioned, close is bad. Use a flush. And hope netsh uses a flush back to you...

I'd try:
PrintWriter netshWriter = new PrintWriter(netshOutputStream, true); // auto-flush writer
netshWriter.println(command);
No close()ing the stream, flush the stream automatically, and uses a writer to send character data rather than relying on the platforms "native character set".

You do definitely need to remove the close, else you'll never be able to execute another command. When you say "it won't work" once the close() call removed, do you mean no commands are processed?
Chances are that after you send the bytes for the command, you need to send some kind of confirmation key for the process to start, well, processing it. If you'd normally enter this from the keyboard it might be as simple as a carriage return, otherwise it might need to be a Ctrl-D or similar.
I'd try replacing the close() line with
netshOutStream.write('\n');
and see if that works. Depending on the software you might need to change the character(s) you send to signify the end of the command, but this general approach should see you through.
EDIT:
It would also be prudent to call
netshOutStream.flush();
after the above lines; without the flush there's no guarantee that your data will be written and in fact, since you're using a BufferedInputStream I'm 99% sure that nothing will be written until the stream is flushed. Hence why the code afterwards blocks, as you're waiting for a response while the process has not seen any input yet either and is waiting for you to send it some.

I've used scanner instead of BufferedReader, just because I like it. So this code works:
Scanner fi = new Scanner(netshProcess.getInputStream());
public void executeCommand(String command) {
System.out.println("Executing: " + command);
String str = "";
netshWriter.println(command);
fi.skip("\\s*");
str = fi.nextLine();
System.out.println(str);
}
It executes both commands.