Packet injection

Packet injection (also known as forging packets or spoofing packets) is a computer networking term that refers to the process of interfering with an established network connection, by means of constructing packets to appear as if they are part of the normal communication stream. The packet injection process allows an unknown third party to disrupt or intercept packets from the consenting parties that are communicating, which can lead to degradation or blockage of users' ability to utilize certain network services or protocols. Packet injection is commonly used in man-in-the-middle attacks and denial-of-service attacks.

Capabilities

By utilizing raw sockets, NDIS function calls, or direct access to a network adapter kernel mode driver, arbitrary packets can be constructed and injected into a computer network. These arbitrary packets can be constructed from any type of packet protocol (ICMP, TCP, UDP, and others) since there is full control over the packet header while the packet is being assembled.

General procedure

Create a raw socket
Create an Ethernet header in memory
Create an IP header in memory
Create a TCP header or UDP header in memory
Create the injected data in memory
Assemble (concatenate) the headers and data together to form an injection packet
Compute the correct IP and TCP or UDP packet checksums
Send the packet to the raw socket

Uses

Packet injection has been used for:

Disrupting certain services (file sharing or HTTP) by Internet service providers and wireless access points^[1]^[2]
Compromising wireless access points and circumventing their security
Exploiting certain functionality in online games
Determining the presence of internet censorship
Allows for custom packet designers to test their custom packets by directly placing them onto a computer network
Simulation of specific network traffic and scenarios
Testing of network firewalls and intrusion detection systems
Computer network auditing and troubleshooting computer network related issues

Detecting packet injection

Through the process of running a packet analyzer or packet sniffer on both network service access points trying to establish communication, the results can be compared. If point A has no record of sending certain packets that show up in the log at point B, and vice versa, then the packet log inconsistencies show that those packets have been forged and injected by an intermediary access point. Usually TCP resets are sent to both access points to disrupt communication.^[2]^[3]^[4]

Software

lorcon, part of Airpwn
KisMAC
pcap
Winsock
CommView for WiFi Packet Generator
Scapy
Kali Linux (BackTrack was the predecessor)

External links

References

This article is issued from Wikipedia - version of the 7/17/2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.