会话劫持（Session hijacking），是一种网络攻击手段，黑客可以通过破坏已创建的数据流而实现劫持。

• 中间人攻击（Man-in-the-Middle Attack，一般简称MITM攻击）
• SMB会话劫持

In computer science, session hijacking, sometimes also known as cookie hijacking is the exploitation of a valid computer session—sometimes also called a session key—to gain unauthorized access to information or services in a computer system. In particular, it is used to refer to the theft of a magic cookie used to authenticate a user to a remote server. It has particular relevance to web developers, as the HTTP cookies used to maintain a session on many web sites can be easily stolen by an attacker using an intermediary computer or with access to the saved cookies on the victim's computer (see HTTP cookie theft).