Home > CAPEC List > CAPEC-299: TCP SYN Ping (Version 3.0)  

CAPEC-299: TCP SYN Ping

Attack Pattern ID: 299
Abstraction: Detailed
Status: Stable
Presentation Filter:
+ Description
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. Due to the different responses from open and closed ports, SYN packets can be used to determine the remote state of the port. A TCP SYN ping is also useful for discovering alive hosts protected by a stateful firewall. In cases where a specific firewall rule does not block access to a port, a SYN packet can pass through the firewall to the host and solicit a response from either an open or closed port. When a stateful firewall is present, SYN pings are preferable to ACK pings because a stateful firewall will typically drop all unsolicited ACK packets as they are not part of an existing or new connection. TCP SYN pings often fail when a stateless ACL or firewall is configured to blanket-filter incoming packets to a port. The firewall device will discard any SYN packets to a blocked port. Often, an adversary will alternate between SYN and ACK pings to discover if a host is alive.
+ Typical Severity

Low

+ Relationships

The table(s) below shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.

+ Relevant to the view "Mechanisms of Attack" (CAPEC-1000)
NatureTypeIDName
ChildOfStandard Attack PatternStandard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.292Host Discovery
+ 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.
+ Skills Required
[Level: Low]
The adversary needs to know how to craft and send protocol commands from the command line or within a tool.
+ Resources Required
SYN pings can be performed via the use of a port scanner or by raw socket manipulation using a scripting or programming language. Packet injection tools are also useful for this purpose. Depending upon the technique used it may also be necessary to sniff the network in order to see the response.
+ Consequences

The table below specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

ScopeImpactLikelihood
Confidentiality
Other
Confidentiality
Access Control
Authorization
Bypass Protection Mechanism
Hide Activities
+ References
[REF-33] Stuart McClure, Joel Scambray and George Kurtz. "Hacking Exposed: Network Security Secrets & Solutions". Chapter 2: Scanning, pg. 48. 6th Edition. McGraw Hill. 2009.
[REF-128] Defense Advanced Research Projects Agency Information Processing Techniques Office and Information Sciences Institute University of Southern California. "RFC793 - Transmission Control Protocol". Defense Advanced Research Projects Agency (DARPA). 1981-09. <http://www.faqs.org/rfcs/rfc793.html>.
[REF-34] Gordon "Fyodor" Lyon. "Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning". Section 3.6.2 TCP SYN Ping, pg. 61. 3rd "Zero Day" Edition,. Insecure.com LLC, ISBN: 978-0-9799587-1-7. 2008.
[REF-125] Mark Wolfgang. "Host Discovery with Nmap". 2002-11. <http://nmap.org/docs/discovery.pdf>.
+ Content History
Submissions
Submission DateSubmitterOrganization
2014-06-23CAPEC Content TeamThe MITRE Corporation
Modifications
Modification DateModifierOrganization
2018-07-31CAPEC Content TeamThe MITRE Corporation
Updated Attacker_Skills_or_Knowledge_Required, Description, Description Summary, Related_Weaknesses, Resources_Required

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Page Last Updated or Reviewed: July 31, 2018