🖊️ Author: Nairuz Abulhul

🌐 Blog: R3dbuck3t

Table of Contents

SNMP Overview

Simple Network Management Protocol (SNMP) was created to monitor network devices. This protocol can also be used to handle configuration tasks and change settings remotely

SNMP-enabled hardware includes routers, switches, servers, IoT devices, and many other devices that can also be queried and controlled using this standard protocol.

I**n classical communication, it is always the client who actively requests information from the server, SNMP also enables the use of so-called traps over UDP port 162. These are data packets sent from the SNMP server to the client without being explicitly requested. If a device is configured accordingly, an SNMP trap is sent to the client once a specific event occurs on the server-side.

For the SNMP client and server to exchange the respective values, the available SNMP objects must have unique addresses known on both sides. This addressing mechanism is an absolute prerequisite for successfully transmitting data and network monitoring using SNMP.**

MIB

To ensure that SNMP access works across manufacturers and with different client-server combinations, the Management Information Base (MIB) was created. MIB is an independent format for storing device information.

A MIB is a text file in which all queryable SNMP objects of a device are listed in a standardized tree hierarchy. It contains at least one Object Identifier (OID), which, in addition to the necessary unique address and a name, also provides information about the type, access rights, and a description of the respective object. MIB files are written in the Abstract Syntax Notation One (ASN.1) based ASCII text format. The MIBs do not contain data, but they explain where to find which information and what it looks like, which returns values for the specific OID, or which data type is used.

OID

An OID represents a node in a hierarchical namespace. A sequence of numbers uniquely identifies each node, allowing the node's position in the tree to be determined. The longer the chain, the more specific the information. Many nodes in the OID tree contain nothing except references to those below them. The OIDs consist of integers and are usually concatenated by dot notation.

Community Strings

Community strings can be seen as passwords that are used to determine whether the requested information can be viewed or not

Footprinting the Service

• **1.3.6.1.2.1.25.4.2.1.2** for enumerating windows processes on the target machine
• hrsWInstalledName for installed applications on the target machine
• **1.3.6.1.2.1.6.13.1.3** for enumerates the open TCP ports
• 1.3.6.1.2.1.25.6.3.1.2 for enumerates installed software
• SNMP enumeration is a process of enumerating user accounts and devices on a target system using SNMP.
• SNMP consists of a manager and an agent; agents are embedded on every network device, and the manager is installed on a separate computer.