CAPEC-299 TCP SYN Ping

CAPEC ID: 299

CAPEC-299 Metadata

Likelihood of Attack

High

Typical Severity

Low

Overview

Summary

An adversary uses TCP SYN packets as a means towards host discovery. Typical RFC 793 behavior specifies that when a TCP port is open, a host must respond to an incoming SYN "synchronize" packet by completing stage two of the 'three-way handshake' - by sending an SYN/ACK in response. When a port is closed, RFC 793 behavior is to respond with a RST "reset" packet. This behavior can be used to 'ping' a target to see if it is alive by sending a TCP SYN packet to a port and then looking for a RST or an ACK packet in response.

Prerequisites

The ability to send a TCP SYN packet to a remote target. Depending upon the operating system, the ability to craft SYN packets may require elevated privileges.

Potential Solutions / Mitigations

No specific solutions listed.

Related Weaknesses (CWE)

CWE ID Description
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

Related CAPECs

CAPEC ID Description
CAPEC-292 An adversary sends a probe to an IP address to determine if the host is alive. Host discovery is one of the earliest phases of network reconnaissance. The adversary usually starts with a range of IP addresses belonging to a target network and uses various methods to determine if a host is present at that IP address. Host discovery is usually referred to as 'Ping' scanning using a sonar analogy. The goal is to send a packet through to the IP address and solicit a response from the host. As such, a 'ping' can be virtually any crafted packet whatsoever, provided the adversary can identify a functional host based on its response. An attack of this nature is usually carried out with a 'ping sweep,' where a particular kind of ping is sent to a range of IP addresses.

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