CAPEC-322 — TCP (ISN) Greatest Common Divisor Probe
CAPEC-322: TCP (ISN) Greatest Common Divisor Probe
MITRE CAPEC attack pattern
| Status | Stable |
| Typical severity | Low |
| Likelihood of attack | Medium |
| Catalogue | CAPEC 3.9 (2023-01-24) |
Description
This OS fingerprinting probe sends a number of TCP SYN packets to an open port of a remote machine. The Initial Sequence Number (ISN) in each of the SYN/ACK response packets is analyzed to determine the smallest number that the target host uses when incrementing sequence numbers. This information can be useful for identifying an operating system because particular operating systems and versions increment sequence numbers using different values. The result of the analysis is then compared against a database of OS behaviors to determine the OS type and/or version.
Where this sits in the chain
A finding maps to a weakness (CWE), a weakness is exploited by an attack pattern (CAPEC), and an attack pattern shows up in ATT&CK as observed adversary behaviour. This page is the middle hop.
Weaknesses exploited: CWE-200
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.
Consequences
- Confidentiality: Read Data
- Confidentiality, Access Control, Authorization: Bypass Protection Mechanism, Hide Activities