Firewalk is a tool for network security that uses active reconnaissance techniques.
Firewalk is a useful network security tool that actively performs reconnaissance to determine what layer 4 protocols will be passed through a particular IP forwarding device. The Firewalk project operates by sending out UDP or TCP packets with a TTL greater than what the targeted gateway allows. In the event that the gateway permits the traffic, it will forward the packets to the next hop where they will expire and prompt an ICMP_TIME_EXCEEDED message.
If the gateway does not authorize the traffic, it will likely drop the packets on the floor and there will be no response. To obtain the correct IP TTL that will result in expired packets one beyond the gateway, we must escalate hop-counts in the same way that traceroute functions.
Once we have the gateway hopcount, also known as the "bound" scan, we may begin our recon. It is important to note that while the ultimate destination host does not need to be reached, it must be located downstream on the other side of the gateway from the scanning host.
To utilize Firewalk, you will need to have libnet 1.1.x, lipcap, and libdnet installed. This is an open-source project, and donations are appreciated.
If the gateway does not authorize the traffic, it will likely drop the packets on the floor and there will be no response. To obtain the correct IP TTL that will result in expired packets one beyond the gateway, we must escalate hop-counts in the same way that traceroute functions.
Once we have the gateway hopcount, also known as the "bound" scan, we may begin our recon. It is important to note that while the ultimate destination host does not need to be reached, it must be located downstream on the other side of the gateway from the scanning host.
To utilize Firewalk, you will need to have libnet 1.1.x, lipcap, and libdnet installed. This is an open-source project, and donations are appreciated.
What's New
Version 5.0: N/A