Can Wireshark be used to change the content of packets

Question

Wireshark doesn't seem to be able to change the content of filtered packets in real time.

Does anyone know a symilar software which can change packet content that is filtered.

Finding something like this will really be a life saver

Thanks.

Solution 1

At least on Unices and -like where raw sockets are used, this is not possible, since the packet is copied to userspace and you only work on that copy. Furthermore, sending a packet back through the raw socket may be considered an "outgoing" packet so that it is, in fact, not reinjected to the input path where it should be. Raw sockets were — according to the Linux manpage — designed to implement new protocols, IOW, raw sockets are an "endpoint", not a "passthrough station".

For packet modification in the input path (passthrough-like), each OS has its own set of interfaces. In Linux (you were sort of unspecific as to which you target), that would be the nfqueue mechanism, usable through libnetfilter_queue. And of course, that is how wireshark, if it wanted to (I don't see it doing packet alteration last time I checked), would go about doing this.

Solution 2

Please give Burp Suite a try. It includes a repeater that let's you modify HTTP requests.

Solution 3

No wireshark won't let you change the contents of the packets and place them back on the line. However there are ways to change packets as they pass through the machine. Typically the host is setup with two nics bridged together. One nic is connected to one network and the other nic to the other network. Then as packets pass through this point the host can see them. Now you can use iptables/netfilter and write a module that changes data in the packet. For example you can write something that can remap source ip addresses. It's been a while since I've used netfilter/iptables, so I can't provide anymore details, but I have used it in a previous job to do some neat things with packets while they were inflight. It does mean you need a host machine sitting at network junction points though.

Comments

[Vercingatorix]

Newer versions of wireshark don't support this, unfortunately. See golinuxcloud.com/packet-editing-wireshark-examples