TCP Out‐Of‐State

Introduction:

TCP Out-of-State packets are a critical concern in network security, encompassing various types of packets that do not conform to the expected state of an ongoing TCP connection. This deviation from the expected connection state can lead to a range of issues, including vulnerabilities to Denial of Service (DoS) attacks. In this context, we will explore TCP Out-of-State packet floods, where attackers flood a victim's server or network with a multitude of such misaligned packets.

Understanding TCP Out-of-State Packet Flood Attacks:

In the TCP protocol, maintaining the correct state of a connection is essential for reliable and secure communication. TCP Out-of-State packet flood attacks exploit this requirement by bombarding the victim server with a barrage of packets that deviate from the expected connection states. These out-of-state packets can include not only SYN, FIN, RST, and ACK packets but also packets with various flags set (e.g., URG, PSH) and incorrect sequence numbers.

During a TCP Out-of-State packet flood attack, attackers frequently spoof the source IP addresses of these packets, making it challenging for the victim server to differentiate between legitimate and malicious packets. Consequently, the server's essential resources, including CPU, memory, and network bandwidth, become overwhelmed, leading to service disruption or complete unavailability.

Implications of TCP Out-of-State Packet Flood Attacks:

TCP Out-of-State packet flood attacks can have severe consequences for targeted systems and networks, including:

• Denial of Service (DoS): The sheer volume of out-of-state packets inundates the victim server's resources, resulting in a denial of service for legitimate users. This disrupts critical services, causing financial losses, customer dissatisfaction, and reputational damage.

• Resource Exhaustion: TCP Out-of-State packet floods consume crucial server resources, such as CPU cycles, memory, and network bandwidth. The excessive load imposed by these out-of-state packets can cause the server to become unresponsive, leading to system crashes or severe performance degradation.

• Network Congestion: The high volume of out-of-state packets generated during an attack can saturate network links and infrastructure components. This congestion can have a cascading effect, impacting other devices and services on the network, resulting in widespread disruption.

How the script deals with them:

• Rate-Limits
• Stateful Packet Inspection.
• Other technics.