I need to ask a question about HTTP protocol. I am trying to develop a sandbox (web browser) where any one can surf the website with different identities. Different identity means that on each request to a page will be from different IP address.
Now I don't know how scripts on web servers check the IP address of the one who generated the request. This is possible and I am aware of this. But I need to know whether this is HTTP request header that has the IP address or something else.
Simply speaking, I want to fool the websites. :)
Umair
Uh, the IP address is provided EVERY time you connect to ANYTHING. It has nothing to do with http headers.
See IPv4 -> packet structure -> header
You need to read up on the layers that build up a network from the wires[1] to the application. I think you'll find the the IP address is known long before HTTP gets involved.
See http://en.wikipedia.org/wiki/OSI_model
[1] or photons, or radio waves, or smoke signals...
Related
I have a general networking question but it's related with security aspect.
Here is my case: I have a host which is infected by a malware. The malware creates an http packet to communicate with it's command and control server. While constructing the packet, the IP layer contains the correct IP address of the command and control server. The tcp layer contains the correct port number 80.
Before sending the packet out, the malware modifies the http header to replace the host header with “google.com" instead of it's server address. It then attaches the stolen data with the packet and sends it out.
My understanding is that the packet will get delivered to the correct server because the routing will happen based on the IP.
But can I host a webserver on this IP that would receive all packets with header host google.com and parse it correctly?
Based on my reading on the internet, it is possible but if it is that easy then why have malware authors not adopted this technique to spoof the http headers and bypass traditional domain whitelisting engines.
When you make a request to let's say Apache2 server, what actually Apache does is match your "Host" header with any VirtualHost within server's configuration. Only if it cannot be found / is invalid, Apache will route the request to default virtualhost if it's defined. Basically nothing stops you from changing these headers.
You can simply test it by editing your hosts file and pointing google.com to any other IP - you will be able to handle the google.com domain on your server, but only you will be to use it this way - no one else.
Anything you send inside HTTP headers shouldn't be trusted - it just a guide for your server on how to actually handle the traffic.
The fake host header is just there to trick some deep-inspection firewalls ("it's for Google? you may pass..."). The server on that IP either doesn't care about the host header (default vhost) or is explicitly configured to accept it.
Passing the loot on by using fake headers or just as plain data behind the headers is another trick to fool data loss prevention.
These methods can mislead shallow application-layer inspection but won't pass a decent firewall.
I'm able to make HTTP requests on my local host using client certificates.
I have some logic in my code that can make two requests use the same certificate for their requests, or not, depending on certain conditions.
My localhost is currently pointing to the default 'Welcome to IIS' page.
Is there any way to use Wireshark to detect if the client certificates that are being sent from my machine in separate requests are the same or not?
PS: If someone can suggest a better way of achieving what I'm trying to do here, that'd work as well. I don't necessarily need to use Wireshark. My main objective is to figure if two different requests are sending the same cert or not, as I've mentioned here:
How do I monitor client certs that are being sent via the requests?
Thanks!
I found a way to do this. This guide helped, in summary, yes, you can use Wireshark to examine what client certificates are being sent from the client (or received on the server).
You need to start capturing traffic on Wireshark, only for the period of time when the request(s) is made and processed, and then add the appropriate filters to filter based on the protocol. In my case, I filtered it based on the IP address of the sender and receiver because I knew both.
You'll need the server's certificate to decrypt the messages because they'll be transmitted in encrypted format. You can easily do that by going to Edit -> Preferences. Select Protocols from the menu on the left -> SSL -> Click edit. Add the server's cert and IP, and save the settings.
Suppose computer A sends an HTTP request to a server B, and B wants C to answer it. Is it possible for C to send a response back to A without B intervention and without specific actions from A (as with a 3xx redirection)? Suppose C may not have a public IP address.
That's what a reverse proxy would do. Depending what platform you are on, there are a lot of options.
One way that works on many platforms is e.g. node-http-proxy that you could start on server B. In the most simple case, this one-liner would do:
require('http-proxy').createServer(81, 'serverb').listen(80);
It listens on port 80 and redirects to port 81 on serverb.
See https://github.com/nodejitsu/node-http-proxy for more options.
Of course, there are lots of well-established proxies with a lot more bells and whistles (although node-http-proxy can do https tunneling etc. as well), but configuring those can be more challenging that running this one-liner. It all depends on your use case.
Edit: Reading your comment, this can be done using direct routing. Your question is about HTTP (layer 7), and as direct routing works on a lower layer, higher-level protocols like HTTP work as well. Quote from http://horms.net/projects/has/html/node9.html:
Direct Routing: Packets from clients are forwarded directly to the
back-end server. The IP packet is not modified, so the back-end
servers must be configured to accept traffic for the virtual server's
IP address. This can be done using a dummy interface, or packet
filtering to redirect traffic addressed to the virtual server's IP
address to a local port. The back-end server may send replies directly
back to the client. That is if a host based layer 4 switch is used, it
may not be in the return path.
In general on any non-HTTP server. Would there be a way to detect what domain was used to reach the IP?
I know HTTP servers get the domain passed within the request header, but would this be possible with any other server that does not require this information to be received from the client?
I'm especially looking for a way to do this with the minecraft server (Bukkit) so my preferred language (if needed for you to answer) would be Java. But I'd like to not have the theories about this language specific.
In general, no, which is why the HTTP protocol includes it in the headers.
In order to reach your server, first a DNS lookup is performed to resolve your IP, which is then followed by the connection itself. These two steps are separate, and hard to link together.
Logging what domain was last requested by a client is tricky, too, as DNS information is often cached, so the DNS request may not even reach your DNS server before being answered.
If it isn't cached, it also often isn't directly looked up by the end client, but rather by a caching DNS server operated, for instance, by the ISP.
No. The only way to get the DNS name used to connect to a server is to have the client provide it.
No, if there are no means for this in the protocol itself like the Host header in HTTP you cannot find out which hostname was used on the client to resolve your IP address.
My website is suffering from an apparent bot which GETs a particular URL 5 times within a second, waits exactly 2 minutes, then repeats. The request is coming from the same IP address each time, and I have not observed any malicious payload, so I'm undecided on whether it is some form of spam bot. The User-Agent claims to be IE6, which is always suspicious in such an obviously non-human request pattern.
Anyway, I have done a reverse lookup on the IP and have located a contact at that domain, but am I wasting my time trying to get in touch with them? If it's a spam bot, won't the IP address be spoofed? How common is IP address spoofing in HTTP spammers? Does the HTTP protocol make it difficult in any way?
If you spoof the IP, you won't get any response to your http request. Other than that, the http protocol doesn't make spoofing any easier or harder.
However, the IP address will be that of the last proxy server or load balancer between the source and your server, so if it is malicious, I would expect they're going through some open proxy and you won't easily be able to trace them back.
If it's just accidental misconfiguration, you're in with more of a chance.
Does the URL they are returning exist on your site?
Can you configure your web server to return an error (401 Forbidden , 500 Internal server error, 301 permanent redirect, perhaps) only to GETs from that address? If the other end starts getting errors maybe they'll investigate and fix things)
You should contact the persons in charge of the domain. Usually, the IP address won't be spoofed (that's hard). Most probably, one of there computers got infected by malicious software, and they definitely want to know that. It's more about doing a favour to them than about your own network security.