How can you identify advanced persistent threats (APTs) using TCP header analysis?

TCP header contains critical information 4 data transmission.Elements like source & destination ports, sequence & acknowledgment numbers, flags (such as SYN, ACK, FIN), & window size provide insights. APTs often manipulate these fields. Unusual patterns, like persistent connections to specific ports, abnormal flag sequences, or inconsistent window sizes, may indicate APT activity. Analyzing packet lengths and timings also helps detection, as APTs may exhibit non-standard behavior. By scrutinizing TCP headers for anomalies, we can uncover potential APTs attempting to exploit network vulnerabilities, enabling timely mitigation. There are many tools, but one i personally love is “WireShark” & it’s free! Mastering it - makes life easier for us!

large number of SYN packets without finishing the three-way handshake,Sending packets with multiple flags set,Unexpected deviations from the expected sequence pattern in sequence numbers, such as abrupt jumps or gaps, could be signs of spoofing or hijacking attempts on TCP sessions.

Focus on Anomalies for more critical findings Unusual Flag Combinations checks Uncommon Port Utilization monitor for vunlurablitity Suspicious Source/Destination Patterns match to identify threats Long Connection Durations checks Baseline Your Network: Understand 'normal' TCP traffic patterns in your environment. This makes identifying anomalies significantly easier. Leverage Threat Intelligence: Utilize threat intelligence feeds to cross-reference known APT techniques and indicators of compromise (IOCs)

TCP wraps each data packet with a header containing 10 mandatory fields totaling 20 bytes . Each header holds information about the connection and the current data being sent. The 10 TCP header fields are as follows: Source port – The sending device's port. Destination port – The receiving device's port.

Wireshark is the most powerful tool to capture the tcp packets.It contains the data packets,to analyse in the digital forensics.

If you suspect that you have detected an APT using TCP header analysis, you need to take immediate and appropriate actions to contain, eradicate, and recover from the attack. Isolating affected systems, collecting and preserving evidence, removing the malware and restoring the systems, and improving the security posture are all important steps to take. Disconnecting the compromised systems from the network and blocking suspicious IP addresses, ports, or domains at the firewall or router level can help prevent further communication with the attacker or command and control server. Collecting network traffic logs, TCP headers, system logs, memory dumps, disk images, and other data can help identify the source, scope, and impact of the attack.

It provides a connection-oriented reliable service, which means that it guarantees the delivery of data packets. If the data packet is lost across the network, then the TCP will resend the lost packets. It provides a flow control mechanism using a sliding window protocol

1. All the APTs cannot be identified by the TCP headers 2. It also requires correlations between different data sources 3. Needs constant update on signature and IOCs

I have a workspace in wireshark and I captured the data that user sent to the server ,By that I made analysing them.It was my experience in wireshark.