Network Sniffing

Network Sniffing [T1040]

Information

• Name: Network Sniffing

• ID: T1040

• Tactics: TA0006, TA0007

Introduction

Network sniffing, identified as technique T1040 in the MITRE ATT&CK framework, involves capturing network traffic to intercept sensitive information. Attackers use sniffing to monitor data flowing across networks, extracting credentials, personally identifiable information, intellectual property, and other confidential data. It is categorized under the "Credential Access" and "Discovery" tactics, highlighting its role in reconnaissance and credential theft.

Deep Dive Into Technique

Network sniffing involves passively or actively capturing data packets traversing a network. This technique can be executed using various methods and tools:

• Passive Sniffing:

  • Conducted on networks using hubs or unsecured wireless networks.

  • Attackers employ packet capture tools such as Wireshark, tcpdump, or Ettercap.

  • Passive sniffing does not inject traffic or interfere with network operations, making it stealthy and difficult to detect.

• Active Sniffing:

  • Performed in switched environments using techniques like ARP spoofing, MAC flooding, or DNS poisoning.

  • Attackers redirect network traffic through their systems to capture packets.

  • Tools commonly used include Ettercap, Cain & Abel, BetterCAP, and dsniff.

• Mechanisms and Procedures:

  • ARP Spoofing: Attacker sends falsified ARP messages, associating their MAC address with the IP address of another legitimate host, causing traffic to route through their system.

  • MAC Flooding: Overwhelming a network switch with fake MAC addresses, causing it to act as a hub and broadcast packets to all ports.

  • DNS Poisoning: Manipulating DNS caches to redirect traffic through attacker-controlled servers.

  • Wireless Sniffing: Capturing data packets transmitted over unsecured or weakly secured wireless networks.

When this Technique is Usually Used

Network sniffing is employed across various attack scenarios and stages, including:

• Reconnaissance Stage:

  • Attackers gather intelligence about network topology, services, and traffic patterns.

  • Identify potential targets, vulnerabilities, and sensitive data flows.

• Credential Harvesting:

  • Capture usernames, passwords, session tokens, and API keys transmitted in clear text or weakly protected protocols (e.g., FTP, HTTP, Telnet).

• Man-in-the-Middle (MitM) Attacks:

  • Intercept and manipulate traffic between two communicating parties.

  • Alter data or inject malicious payloads into legitimate communications.

• Lateral Movement and Persistence:

  • Capture authentication credentials to move laterally within a network.

  • Maintain persistence by monitoring network communications and adapting attack strategies.

• Data Exfiltration:

  • Monitor legitimate network traffic to identify valuable data and exfiltrate it without detection.

How this Technique is Usually Detected

Detection of network sniffing involves various methods, tools, and indicators of compromise (IoCs):

• Network Intrusion Detection Systems (NIDS):

  • Tools like Snort, Suricata, Zeek (Bro), and Security Onion detect anomalous traffic patterns and protocol violations indicative of sniffing activities.

• ARP Monitoring and Spoofing Detection:

  • Tools such as ARPwatch, XArp, or built-in ARP monitoring capabilities in SIEM solutions identify ARP spoofing attempts.

• Switch Port Security:

  • Network devices configured to detect MAC flooding attacks and unusual MAC address activity.

• DNS Monitoring and Protection:

  • Monitoring DNS traffic for anomalies using tools like DNSQuerySniffer, DNS logs analysis, or DNSSEC deployment.

• Wireless Intrusion Detection Systems (WIDS):

  • Solutions like Kismet or AirMagnet detect unauthorized wireless sniffing and rogue access points.

• Endpoint Detection and Response (EDR):

  • Identify suspicious network interfaces, promiscuous mode usage, or installation of unauthorized packet capturing tools.

• Indicators of Compromise (IoCs):

  • Unusual ARP table entries or persistent ARP cache changes.

  • Sudden increase in broadcast traffic or MAC address table overflow.

  • Presence of unauthorized packet capture software or promiscuous mode network adapters.

  • DNS anomalies, such as unexpected DNS responses or redirections.

Why it is Important to Detect This Technique

Early detection of network sniffing is critical due to its significant potential impacts:

• Credential Compromise:

  • Attackers can gain unauthorized access to user accounts, administrative credentials, and sensitive systems, leading to privilege escalation.

• Loss of Confidentiality:

  • Sensitive information, intellectual property, financial data, and personally identifiable information (PII) can be intercepted and exfiltrated.

• Operational Disruption:

  • Active sniffing methods, such as ARP spoofing or DNS poisoning, can degrade network performance, disrupt legitimate communications, and cause service outages.

• Regulatory and Compliance Risks:

  • Organizations may face legal consequences, financial penalties, and reputational damage for failing to protect sensitive data.

• Facilitation of Advanced Persistent Threats (APTs):

  • Undetected sniffing can enable attackers to maintain persistent access, conduct further reconnaissance, and execute sophisticated attacks.

Timely detection allows organizations to respond promptly, mitigate potential damage, and implement proactive countermeasures.

Examples

Real-world examples involving network sniffing:

• Operation Aurora (2010):

  • Attackers targeted Google and several other large companies.

  • Sniffed network traffic to capture sensitive data and credentials.

  • Impact: Significant intellectual property theft and compromise of sensitive user data.

• DarkHotel APT Group:

  • Attackers targeted executives staying in luxury hotels using compromised Wi-Fi networks.

  • Sniffed traffic to obtain credentials and install malware on victims' devices.

  • Tools used: Wireshark, Ettercap, custom malware.

  • Impact: Credential theft, espionage, and persistent access to corporate networks.

• FIN7 Cybercrime Group:

  • Conducted ARP spoofing attacks to intercept financial data and payment card information in retail environments.

  • Tools used: Ettercap, BetterCAP, custom scripts.

  • Impact: Massive financial losses, regulatory fines, and reputational damage for affected businesses.

• Magecart Attacks:

  • Attackers injected malicious JavaScript into e-commerce sites, sniffing payment card data transmitted by customers.

  • Tools used: Custom JavaScript sniffers, compromised CDN services.

  • Impact: Theft of millions of payment card details, financial losses, and reputational harm.

• Wi-Fi Pineapple Attacks:

  • Attackers deployed rogue wireless access points to intercept wireless traffic.

  • Tools used: Wi-Fi Pineapple, Aircrack-ng, Kismet.

  • Impact: Credential harvesting, unauthorized access, and espionage.

These examples illustrate the diverse scenarios, tools, and impacts associated with network sniffing, underscoring the importance of robust detection and mitigation strategies.