👉 Overview
👀 What ?
Pentesting NetBIOS refers to the process of exploiting the vulnerabilities in the Network Basic Input/Output System (NetBIOS), a software protocol that allows applications on separate computers to communicate over a local area network (LAN). It's commonly used in Windows-based systems.
🧐 Why ?
Pentesting NetBIOS is crucial as it is a common protocol found in corporate networks, especially those that rely heavily on Windows-based systems. If left unchecked, vulnerabilities in NetBIOS can lead to unauthorized access, data breaches, and potential compromise of the entire network.
⛏️ How ?
Performing a pentest on NetBIOS involves several steps. First, you need to enumerate NetBIOS to identify active hosts in the network. Tools like Nbtscan or NMAP can be used in this process. Next, you would establish a null session with the target, which can be done using tools like Enum4linux or NBTEnum. Once the null session is established, information like user lists, machine lists, and shared resources can be extracted. Finally, the pentester would attempt to exploit any identified vulnerabilities to gain unauthorized access or disrupt the network's operations.
⏳ When ?
Pentesting NetBIOS should be performed regularly, especially when new systems are added to the network or after significant changes have been made to the network's infrastructure. Regular pentesting helps to ensure that any vulnerabilities are identified and addressed promptly.
⚙️ Technical Explanations
NetBIOS operates at the session layer of the OSI model, allowing applications on separate machines to communicate over a LAN. It was initially designed for early versions of Windows and is still prevalent in most Windows-based networks. It uses ports 137 for name services, 138 for datagram services, and 139 for session services. These ports are often the target of pentesters as they can reveal valuable information about the network, including the NetBIOS name table for each device, which can contain details such as the device's name, its domain, and the version of Windows it's running. Using this information, a pentester could potentially identify weak points in the network's security and exploit them.