Direct Network Flood
Direct Network Flood [T1498.001]
Information
Introduction
Direct Network Flood (T1498.001) is a sub-technique within the MITRE ATT&CK framework that falls under the broader category of Network Denial of Service (DoS) attacks. This sub-technique specifically refers to scenarios where adversaries flood a network or system with excessive traffic, overwhelming resources and causing legitimate requests to fail or become significantly delayed. The primary objective is to impair availability, disrupt services, or degrade performance, creating opportunities for attackers to achieve broader strategic goals.
Deep Dive Into Technique
Direct Network Flood attacks involve intentionally saturating network bandwidth or exhausting system resources through high volumes of traffic. Attackers typically leverage various methods and protocols to generate this excessive traffic. Common execution methods and mechanisms include:
UDP Floods: Attackers send large volumes of User Datagram Protocol (UDP) packets to random ports on the targeted host, causing the system to respond with ICMP "destination unreachable" messages and consuming bandwidth and processing power.
ICMP Flood (Ping Flood): Excessive Internet Control Message Protocol (ICMP) echo requests (ping requests) are sent to a target system, forcing it to respond continuously, thereby consuming bandwidth and processing resources.
TCP SYN Flood: Attackers initiate numerous TCP handshake requests (SYN packets) without completing the handshake, exhausting the targeted system’s connection backlog and preventing legitimate connections.
HTTP/HTTPS Flood: Attackers generate high volumes of HTTP or HTTPS requests, typically targeting web servers, to exhaust resources such as processing capacity, memory, and network bandwidth.
Amplification Attacks: Attackers spoof the victim's IP address, sending small requests to third-party servers (such as DNS, NTP, or SNMP servers), which then respond with significantly larger responses directed toward the victim, amplifying the volume of traffic.
Real-world procedures typically involve botnets or distributed networks of compromised devices (DDoS attacks) to generate massive volumes of traffic. Attackers may also employ specialized tools and scripts designed to automate the flooding process, maximizing the impact and scale of the attack.
When this Technique is Usually Used
Direct Network Flood attacks are commonly employed in various attack scenarios and stages, including:
Initial Access and Reconnaissance:
Disrupting network defenses or monitoring systems to mask other malicious activities.
Testing network capacity and response to assess target resilience.
Resource Exhaustion and System Disruption:
Overwhelming critical infrastructure to degrade or deny services, causing operational downtime.
Targeting specific services (e.g., web applications, DNS services, authentication servers) to disrupt availability.
Diversion and Distraction:
Drawing attention and resources away from other concurrent malicious activities, such as data exfiltration or lateral movement.
Extortion and Ransom Situations:
Threatening or executing DDoS attacks against organizations to demand ransom payments or compliance with attacker demands.
Political or Ideological Motivations:
Conducting attacks against government entities, financial institutions, or media outlets to express political or ideological statements.
How this Technique is Usually Detected
Detection of Direct Network Flood attacks typically involves monitoring network traffic, analyzing anomalies, and employing specialized detection tools. Common detection methods, tools, and indicators of compromise (IoCs) include:
Network Traffic Monitoring and Analysis:
Identifying sudden spikes in network traffic volumes that significantly deviate from normal baselines.
Monitoring unusual patterns of traffic from specific IP addresses or geographic locations.
Intrusion Detection and Prevention Systems (IDS/IPS):
Detection of anomalous traffic patterns, malformed packets, or protocol violations.
Signature-based detection for known attack tools and methods.
Security Information and Event Management (SIEM) Systems:
Correlating logs and alerts from multiple sources to identify coordinated flooding attempts.
Real-time alerting on suspicious traffic patterns and resource exhaustion events.
NetFlow and Traffic Analytics Tools:
Analyzing flow data to detect unusual traffic volumes, packet sizes, and connection attempts.
Specific Indicators of Compromise (IoCs):
Sudden increase in ICMP, UDP, or TCP SYN packets.
Unusual volumes of traffic originating from multiple IP addresses or unusual geographic regions.
High volume of incomplete TCP handshakes or connection resets.
Logs indicating resource exhaustion, network congestion, or degraded service performance.
Why it is Important to Detect This Technique
Early detection of Direct Network Flood attacks is crucial due to the potential severe impacts on systems, networks, and organizational operations. Key reasons for the importance of timely detection include:
Minimizing Downtime and Service Disruption:
Early detection allows organizations to implement mitigation measures promptly, maintaining business continuity and minimizing operational downtime.
Protecting Critical Infrastructure:
Preventing attackers from overwhelming critical services, such as financial transactions, healthcare systems, and emergency response networks.
Preventing Secondary Attacks:
Identifying and mitigating initial flooding attacks can prevent attackers from using the distraction to conduct secondary, potentially more damaging, attacks (e.g., data exfiltration or ransomware deployment).
Reducing Financial and Reputational Damage:
Maintaining service availability and performance reduces financial losses and preserves customer trust and brand reputation.
Legal and Compliance Considerations:
Organizations may face regulatory penalties or legal consequences if critical services or data are compromised or unavailable due to inadequate detection and response.
Examples
Real-world examples of Direct Network Flood attacks include various high-profile incidents, attack scenarios, and tools:
GitHub DDoS Attack (2018):
Attackers leveraged memcached servers in an amplification attack, sending spoofed requests to exposed servers and flooding GitHub with 1.35 Tbps of traffic.
Resulted in brief service disruption, mitigated by rapid response and traffic filtering.
Dyn DNS Attack (2016):
Attackers used the Mirai botnet, consisting of compromised IoT devices, to launch massive UDP flood attacks against DNS provider Dyn.
Caused significant outages affecting major websites and services, including Twitter, Netflix, and Spotify.
Estonian Cyberattacks (2007):
Politically motivated attackers targeted Estonian government and financial institutions using ICMP, UDP, and TCP SYN flood attacks.
Resulted in widespread disruption of government services, financial transactions, and internet access.
Tools Commonly Used:
LOIC (Low Orbit Ion Cannon): Popular open-source tool for HTTP, UDP, and TCP floods.
HOIC (High Orbit Ion Cannon): Advanced version of LOIC, capable of generating higher traffic volumes.
hping3: Command-line tool used for crafting custom TCP, UDP, and ICMP packets for flooding attacks.
Mirai Botnet: Malware-infected IoT devices used extensively for massive DDoS attacks.
Memcached Amplification: Exploits vulnerable memcached servers to amplify attack traffic volume significantly.
These examples demonstrate the wide-ranging impacts, techniques, and motivations behind Direct Network Flood attacks, underscoring the importance of effective detection and mitigation strategies.
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