The Basics of Network Sniffing: How Does It Work?

What is network sniffing?

According to MITRE ATT&CK, network sniffing refers to using the network interface on a system to monitor or capture information sent over a wired or wireless connection.

To put it simply, network sniffing is a technique employed by adversaries to observe and capture data as it travels through a network to steal the target's data. Specific tools or software are used to intercept and analyze the data that is being transmitted, like emails, website visits, or login details. By examining the content of data packets exchanged between devices, network sniffing enables attackers to gain insights into network activity, identify potential security weaknesses, or illicitly obtain access to confidential data.

When adversaries intercept and analyze network traffic, they can acquire sensitive information like login credentials, financial data, or personal details. This can be used for malicious purposes, including identity theft, financial fraud, or gaining unauthorized access to systems and resources. They can also identify vulnerabilities in the network infrastructure or the behavior of users. This enables them to craft targeted and sophisticated attacks leading to significant damage, including data breaches, system compromise, loss of privacy, and financial loss.

Despite network sniffing being primarily used by adversaries with hopes of successful network breaches, it can also be used to improve an organization's security posture. It can provide insights into a network's operations and user behavior, allowing the IT staff or ethical hackers to improve the organization's cybersecurity measures. They can gain extensive understanding of how the network functions and the patterns and actions of its users, ultimately leading to improvements in overall cybersecurity posture for the organization.

Types of network sniffing techniques:

In general, network sniffing techniques can be categorized into two main groups:

• sniffing
• Passive sniffing

• Active sniffing: This is the technique used by attackers to transmit modified packets to one or more targets in a network to obtain sensitive information. This entails the attacker interacting directly with the target system by sending packets and receiving responses. The attacker employs this technique to compromise switches by transmitting forged MAC addresses.

  This sub-type of sniffing can be seen in man-in-the middle attacks where the attacker intercepts the communication between two parties and sniffs sensitive data.

• Passive sniffing: In this technique, the attackers monitor network traffic by capturing the data and not sending any data packets in return. Additionally, it is less likely to attract suspicion than active sniffing because it does not entail any interaction with the target systems.

  The attacker obtains access to the network infrastructure and can intercept and monitor network traffic by connecting to the hub. This enables them to listen and monitor the data being sent across LAN devices.

  This sub-type of sniffing can be seen in Local Area Network (LAN) sniffing where the communication between two devices connected to a LAN is intercepted and the data packets are sniffed without intervening.

How does network sniffing affect your organization?

Sniffing attacks may disclose sensitive information such as, IP addresses, login credentials, network protocols and patterns, carried over a network, resulting in breaches. This might result in identity theft, financial loss, or unauthorized account access.

Attackers can obtain insight into network vulnerabilities and exploit them to gain unauthorized access to systems, devices, or applications by collecting network packets.

This gives them the ability to breach network security, install malware, and engage in other harmful actions. Attackers may inject malicious code into target systems, which could give them control over devices or access to sensitive data.

Any disruption in network traffic might lead to communication issues and delayed network performance. Sniffing attacks can disrupt network operations, especially if attackers perform a denial-of-service (DoS) attack alongside the sniffing activity. By overwhelming network resources or introducing malicious traffic, DoS attacks can cause network downtime, impacting business operations, and resulting in financial losses.

Depending on the type of data revealed during a sniffing attack, there may be legal consequences. Legal action, fines, or penalties might be levied against businesses who don't secure sensitive client data.

Cloud-based environments also fall victim to network sniffing as data could be exposed if transmitted without proper encryption. Through capturing and analyzing network traffic, attackers have the potential to discover vulnerabilities, flaws, or misconfigurations within a cloud-based environment. These can be utilized to gain unauthorized entry to sensitive data or exert control over the cloud infrastructure.

How do you prevent network sniffing attacks?

• To protect data transfer over the network, use encryption methods such as HTTPS, SSL/TLS, or VPNs. Encryption guarantees that the data stays unreadable and secure even if intercepted.
• Monitor network traffic on a regular basis for signals of unusual behavior. Sniffing attacks can be detected using intrusion detection systems, or SIEM solutions.
• Use strong firewalls and access control methods to filter and regulate network traffic. Set up rules to limit traffic to the needed ports and protocols, and configure them to deny unauthorized access attempts.
• To prevent unauthorized access to systems and services, use robust authentication techniques such as 2FA or MFA. This mitigates the risk of sniffing attacks on login credentials.

Detecting network sniffing attacks using a SIEM solution

ManageEngine Log360, being a comprehensive SIEM solution, implements the MITRE ATT&CK framework to increase the efficiency of an organization's security posture. Using this framework, organizations can widen their security capabilities to facilitate early detection and effective incident response.

Log360 can help you by:

• Expediting effective threat resolution Log360's attack detection module is integrated with ATT&CK's incident management framework for speedy resolution.
• Spotting deviant user and entity behavior such as logons at an unusual hour, excessive logon failures, and file deletions from a host that is not generally used by a particular user.
• Proactively searching for advanced security threats and cyber criminals lurking in your network by utilizing a real-time event response system that alerts you about critical events and offers log search options to detect and stop malicious activities.
• Alerting about behavior-based security events through Log360's real-time alert system. You can get instant notifications via SMS and email, allowing security administrators to quickly tend to detected security threats and respond to them.
• Correlating security events and identifying threat patterns across your network.

Log360 is a unified SIEM solution with integrated DLP and CASB capabilities that detects, prioritizes, investigates, and responds to security threats. It combines threat intelligence, machine learning-based anomaly detection, and rule-based attack detection techniques to detect sophisticated attacks, and offers an incident management console for effectively remediating detected threats. Log360 provides holistic security visibility across on-premises, cloud, and hybrid networks with its intuitive and advanced security analytics and monitoring capabilities.