CAPEC Details
Name TCP (ISN) Counter Rate Probe
Likelyhood of attack Typical severity
Medium Low
Summary This OS detection probe measures the average rate of initial sequence number increments during a period of time. Sequence numbers are incremented using a time-based algorithm and are susceptible to a timing analysis that can determine the number of increments per unit time. The result of this analysis is then compared against a database of operating systems and versions to determine likely operation system matches.
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.