CAPEC Details
Name TCP (ISN) Sequence Predictability Probe
Likelyhood of attack Typical severity
Medium Low
Summary This type of operating system probe attempts to determine an estimate for how predictable the sequence number generation algorithm is for a remote host. Statistical techniques, such as standard deviation, can be used to determine how predictable the sequence number generation is for a system. This result can then be compared to a database of operating system behaviors to determine a likely match for operating system and version.
Prerequisites The ability to monitor and interact with network communications.Access to at least one host, and the privileges to interface with the network interface card.
Related Weaknesses
CWE ID Description
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
Related CAPECS
CAPEC ID Description
CAPEC-312 An adversary engages in activity to detect the operating system or firmware version of a remote target by interrogating a device, server, or platform with a probe designed to solicit behavior that will reveal information about the operating systems or firmware in the environment. Operating System detection is possible because implementations of common protocols (Such as IP or TCP) differ in distinct ways. While the implementation differences are not sufficient to 'break' compatibility with the protocol the differences are detectable because the target will respond in unique ways to specific probing activity that breaks the semantic or logical rules of packet construction for a protocol. Different operating systems will have a unique response to the anomalous input, providing the basis to fingerprint the OS behavior. This type of OS fingerprinting can distinguish between operating system types and versions.