| Name |
TCP Initial Window Size Probe |
|
| Likelyhood of attack |
Typical severity |
| Medium |
Low |
|
| Summary |
This OS fingerprinting probe checks the initial TCP Window size. TCP stacks limit the range of sequence numbers allowable within a session to maintain the "connected" state within TCP protocol logic. The initial window size specifies a range of acceptable sequence numbers that will qualify as a response to an ACK packet within a session. Various operating systems use different Initial window sizes. The initial window size can be sampled by establishing an ordinary TCP connection. |
| 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. |
| Solutions | |
| 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. |
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