Disclaimer: This article was written for educational reasons only. Unethical practises such as hacking, IP spoofing, and impersonating a host without permission are strictly prohibited. Always obtain permission first before engaging in a security test.
Introduction:
The Network Layer of the OSI model is responsible for Internet Protocol (IP) and is in charge of the routing and transmission of data over a variety of networks. It may appear that the protection of this layer is primarily centred around address protection, however, this could not be further from the truth. In this piece, we examine the cloak-and-dagger world of Layer 3 hacking, discussing how various attack vectors operate to undermine network security within its integrity, confidentiality, and availability.
Exploitation of Layer 3 Threat Vectors:
- IP Spoofing:
- Method: This concerns generating packets with a specified source IP address different from the true traffic source in an attempt to conceal the traffic origin, or impersonate a device.
- Implementation: An example of a tool that can be used to effect this action is hping3, which users can communicate with by sending packets that could come from any IP address. This phenomenon can serve denial of service attacks in which the perpetrator chokes a specific network by sending fake traffic from different sources, or to circumvent access limitations.
- Example: A cybercriminal can direct a flood of packets towards a server with fabricated source IP addresses, making it seem like numerous devices are launching an attack. This makes it difficult to mitigate the attack.
- BGP Hijacking:
- Technique: An attacker can gain control of internet traffic by announcing a false route in a BGP network and redirecting the traffic through their controlled network.
- Execution: Claiming that a certain network is the most beneficial route for a section of internet traffic allows one to redirect or hijack that traffic.
- Example: Attackers have been known to siphon cryptocurrency from exchanges by unjustly seizing BGP routes and rerouting traffic aimed at the exchanges to their servers.
- ICMP Redirects:
- Technique: Suggesting to a target device that the attacker’s system offers a superior route is an example of altering a routing table using ICMP.
- Execution: An attacker can send messages that allow a particular system to intercept and modify the data, thereby changing the way in which traffic flows.
- Example: A user within an organization could utilize an ICMP redirect to redirect all traffic through their computer to enable surveillance or change data without detection.
- Smurf Attack:
- Technique: A form of DDoS assault where the attacker uses an unidentified source address while sending ICMP echo requests or pings to a broadcast address. When all the devices on the network reply with the spoofed IP address, it becomes flooded with replies.
- Execution: In this case, a network open to broadcasts will need to respond to the pings, which nowadays is increasingly uncommon thanks to security protocols.
- Example: Historically, and even today to some extent, smurf attacks are still useful in bringing down servers due to the capacity overload of responses assisted by numerous devices.
- Fragmentation Attacks:
- Technique: This focuses on evading security layer protocols through fragmentation of packages and insertion of destructive payloads in a fragmented state.
- Execution: Firewalls that are not setup to handle fragmentation can be bypassed by fragmented packets containing large payloads and Revelation of some parts of these packets is possible by reassembling them.
- Example: Fragmentation through packet inspection security and overwhelming the system with the inability to reassemble fragmented packets.
- Defensive Strategies:
- IPsec: Employ IPsec for authentic and confidential communitaction within and between different networks.
- BGP Security: Apply RPKI for BGP route validation and unnecessary route order issues to be dealt with easily.
- Route Filtering: Set up thorough filters on the BGP-edge for incoming and outgoing route requests to eliminate malicious ones.
- ICMP Controls: Restrict or deactivate ICMP redirect message responses, and further be more skeptical in the configuration of ICMP messages.
- DDoS Mitigation: Protect from DDoS attacks that are disguised as floods or other forms of spoofed traffic.
- Monitoring the Network: Analyze IP addresses and fragmented packets to monitor the traffic of a given network for any suspicious activity, using a NIDS to flag anomalies.
Responsibilities of the Ethical Hacker:
Ethical hackers must:
- Restest: Evaluate the effectiveness of a network’s security by attempting to penetrate the system using IP-based assault techniques.
Report: Alert network administrators about the potential danger of Layer 3 and the need for more effective routing protocols.
Recommend: Suggest the implementation of security features, such as route validation, to mitigate the risk of routing and address spoofing.
Final Thoughts:
Layer 3 goes beyond simply shifting data from one location to another; it is a theater of war in which an attacker can unscrupulously take advantage of the internecine routing warfare. These risks must be porched by every cybersecurity expert, because defending the third layer is vital in safeguarding the network as a whole. As such, make it known in your mind that powers of knowledge must act assuring on the ethical use and improvement of cybersecurity.
Disclaimer: The post is meant for educational purposes, raising awareness concerning the third layer and responsible cybersecurity issues.