Threats Faced by Devices

The rapid development of network communications technologies provides people with an unprecedented level of convenience. The drawback to this is that it also brings various security threats. To defend against network attacks, devices that provide a powerful and comprehensive range of security solutions are widely used at the egresses of Internet data centers (IDCs), enterprise networks, and campus networks. These devices, however, are also vulnerable to attacks. To provide better services while also defending against various security threats, devices must therefore have effective protective measures.

The types of security threats that devices typically face are as follows:

• Denial of service (DoS): An attacker sends a large number of requests to a device, aiming to overwhelm the CPU and prevent it from processing the requests promptly. This blocks the service exchange process and internal processing, resulting in a denial of service.
• Information disclosure: Information is accessed without authorization and subsequently disclosed. For example, if sensitive data is stored or sent between service subsystems in plain text, it is easy for attackers to sniff, obtain, and exploit this data.
• Compromised information integrity: Due to the open nature of IP networks, packets are susceptible to tampering by intermediate nodes and man-in-the-middle modification during transmission. For example, if software or patches are tampered with before they are uploaded to a device, the device may be maliciously controlled and attacked when running the software and patches.
• Unauthorized access: Attackers gain system access through brute force cracking and obtain information without authorization by exploiting network configuration vulnerabilities or debugging methods provided by the system.
• Identity spoofing: IP networks are open and lack effective authentication mechanisms for MAC addresses and IP addresses. This means that ARP spoofing and IP address spoofing are likely to occur. If a device receives spoofed addresses, it must continuously update the address entries required for the forwarding process. Incorrect address entries will lead to forwarding interruption, and insufficient MAC address learning capabilities will result in denial of service.
• Replay attack: As mentioned earlier, IP networks are open. This means that terminals cannot authenticate their peers at Layer 3 or lower layers. Attackers can exploit these characteristics to maliciously retransmit specific packets and initiate DoS attacks.
• Computer virus: On a network system, a device functions as both a forwarding node and a manageable network element (NE). If computers on the same network segment are infected with viruses, a large amount of spam traffic is generated, exhausting network bandwidth. In this case, a device functioning as an NE cannot obtain network resources, resulting in unavailable services.
• Misoperations: During network construction, policies may be configured to facilitate service provisioning. If these policies are not deleted immediately after services are provisioned, they may pose security risks that can be exploited by attackers. In addition, misoperations during network construction may lead to configuration errors, which in turn may cause service interruption. For example, loops may occur due to network cables being incorrectly connected or service interruptions may occur due to incorrect protocol configurations. Other examples include incorrect access control policies causing unexpected blocking of traffic; incorrect access channels being activated; or account abuse due to sharing of an administrator account.
• Physical intrusion: A device lacks sufficient protection against physical access. For example, a user may obtain high-priority permissions through a direct physical connection. This means that attackers can gain device access after bypassing protection measures such as the access control and surveillance systems.