CAPEC-306: TCP Window Scan
CAPEC版本: 3.9
更新日期: 2023-01-24
攻击模式描述
An adversary engages in TCP Window scanning to analyze port status and operating system type. TCP Window scanning uses the ACK scanning method but examine the TCP Window Size field of response RST packets to make certain inferences. While TCP Window Scans are fast and relatively stealthy, they work against fewer TCP stack implementations than any other type of scan. Some operating systems return a positive TCP window size when a RST packet is sent from an open port, and a negative value when the RST originates from a closed port. TCP Window scanning is one of the most complex scan types, and its results are difficult to interpret. Window scanning alone rarely yields useful information, but when combined with other types of scanning is more useful. It is a generally more reliable means of making inference about operating system versions than port status.
执行流程
步骤 1 Experiment
An adversary sends TCP packets with the ACK flag set and that are not associated with an existing connection to target ports.
步骤 2 Experiment
An adversary uses the response from the target to determine the port's state. Specifically, the adversary views the TCP window size from the returned RST packet if one was received. Depending on the target operating system, a positive window size may indicate an open port while a negative window size may indicate a closed port.
前提条件
- TCP Window scanning requires the use of raw sockets, and thus cannot be performed from some Windows systems (Windows XP SP 2, for example). On Unix and Linux, raw socket manipulations require root privileges.
所需资源
- The ability to send TCP segments with a custom window size to a host during network reconnaissance. This can be achieved via the use of a network mapper or scanner, or via raw socket programming in a scripting language. Packet injection tools are also useful for this purpose. Depending upon the method used it may be necessary to sniff the network in order to see the response.
后果影响
影响范围: Confidentiality
技术影响: Other
影响范围: Confidentiality Access Control Authorization
技术影响: Bypass Protection Mechanism