The victims can create a new TCP connection in an attempt to resume their communications, but the attacker may be able to reset this new connection too. If a fake reset segment is crafted correctly, the receiver will accept it as valid and close their side of the connection, preventing the connection from being used to exchange further information. In normal, non-nefarious operations, computers send TCP reset segments whenever they receive unexpected TCP traffic and they want its sender to stop sending it.Ī TCP reset attack exploits this mechanism to trick victims into prematurely closing TCP connections by sending them fake reset segments. These messages are called TCP reset segments. In a TCP reset attack, an attacker kills a connection between two victims by sending one or both of them fake messages telling them to stop using the connection immediately. One such tool that they use is the TCP reset attack. To do this, the GFW needs tools that are capable of killing already-established connections. For example, they may want to generally allow traffic to a news website, but to censor specific videos containing banned keywords. Or it could be because they want to analyze the data exchanged over a connection and use this information to decide whether to allow or block it.
This could be because they want to perform slow, out-of-band analysis on the connection, such as correlating it with other activity. However, the GFW may sometimes also want to allow a connection to be made, but to then kill it halfway through. To prevent users from even connecting to forbidden servers, the GFW uses techniques like DNS pollution and IP blocking (both stories for another time). The GFW actively blocks and kills connections to servers inside and outside of the country, as well as passively monitoring internet traffic for proscribed content. The Great Firewall (GFW) is a collection of systems and techniques used by the Chinese government to censor the internet for users inside China. How is the TCP reset attack used in the Great Firewall? Execute the attack against ourselves using a simple Python scriptīefore we analyze the mechanics of the attack, let’s begin by seeing how it is used in the real world.Indeed, understanding the attack’s intricacies will teach you a great deal about the particulars of the TCP protocol, and, as we will soon see, you can even execute the attack against yourself using only a single laptop. Despite this weighty biography, understanding the attack doesn’t require deep prior knowledge of networking or TCP. The attack is believed to be a key component of China’s Great Firewall, used by the Chinese government to censor the internet inside China. Fear of it has caused mitigating changes to be made to the TCP protocol itself. The attack has had real-world consequences. A spoofed TCP segment, crafted and sent by an attacker, tricks two victims into abandoning a TCP connection, interrupting possibly vital communications between them. A TCP reset attack is executed using a single packet of data, no more than a few bytes in size.
0 kommentar(er)
