Attack defense concept and configuration method for the USG2000&5000

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Overview of attack defense

Common network attacks generally intrude or overload web servers (hosts), steal sensitive server data, consume bandwidth resources, or interrupt the services provided by the servers for external users. Certain network attacks directly target at network devices. Such attacks may cause anomalies in network services and bring in adverse impacts, or even interrupt the operations of these services.

Network attacks fall into traffic attacks, scanning and sniffing attacks, malformed-packet attacks, and special-packet attacks. The details are as follows:

?raffic attacks

In a traffic attack, an attacker sends mass useless data to exhaust server resources, causing denial of services on the server. This type of attack has mass data packets sent, overloads devices, and exhausts network bandwidth or device resources. Usually, routers, servers, and firewalls provide limited resources. Once overloaded, they may fail to process normal services, causing denial of services. The commonest traffic attack is flood attacks. In flood attacks, attackers send a large number of seemly legitimate TCP, UDP, and ICMP packets to targets. Some attackers even forge the source addresses to evade detection and monitoring.

?canning and sniffing attacks

Scanning and sniffing attacks mainly refer to IP sweep and port scan. In IP sweep, an attacker constantly sends IP (TCP/UDP/ICMP) packets with changing destination addresses to search existing hosts and networks for a target. In port scan, an attacker scans TCP and UDP ports to detect the operating system and potential services of the target. Through scanning and sniffing, attackers can roughly understand the types of services that targets provide and potential vulnerabilities for further intrusions.

?alformed-packet attacks

In malformed-packet attacks, attackers send defective IP packets to target systems. The target systems may encounter errors or crash when handling such packets. Malformed-packet attacks mainly include Ping-of-Death and Teardrop attacks.

?pecial-packet attacks

In special-packet attacks, attackers use legitimate packets to probe networks or detect data. The packets are legitimate application packets but seldom used on networks.

Other related questions:
Attack defense concept and configuration method for the USG6000
1. Choose Policy > Security Protection > Attack Defense > Anti-DDoS. 2. Bind the interface connecting the NGFW to the Internet. You can use either of the following methods to bind the interface: In Unbound Interfaces, double-click the interface to be bound. The interface is displayed in Bound Interfaces. In Unbound Interfaces, select the interface to be bound and click it. The interface is displayed in Bound Interfaces. 3. (Optional) Configure the NGFW to interwork with the ATIC server. a. Choose Policy > Security Protection > Attack Defense > Anti-DDoS. b. Select the ATIC Interworking check box and enter the IP address of the ATIC server. After the NGFW is configured to interwork with the ATIC server, it can send traffic anomaly logs to the ATIC server. 4. On the DDoS page, click Set Learning Parameters to configure the threshold learning function. 5. Click OK. The threshold learning function takes effect. After this function takes effect, the learning status is displayed under Set Learning Parameters. You can view the threshold learning status. 6. On the DDoS page, select the attack type to be defended against and click Enable. The default threshold is used for defending against each type of attack. 7. Click Apply. 8. If threshold learning is not automatically applied, you must manually trigger the system to apply learning result after threshold learning is complete or set thresholds based on the learning results. Generally, a manually set threshold should be a little bit higher than the learned threshold.

Recommended attack defense configuration on the USG2000&5000&6000
The following attack defense configurations are recommended if there are no special attack defense requirements: firewall defend land enable firewall defend smurf enable firewall defend fraggle enable firewall defend winnuke enable firewall defend source-route enable firewall defend route-record enable firewall defend time-stamp enable firewall defend ping-of-death enable

Configuration of IP sweep attack defense for the USG2000&5000 series on the CLI
You can configure IP sweep attack defense for the USG2000&5000 series on the CLI. 1. Run the firewall defend ip-sweep enable command to enable IP sweep attack defense. By default, IP sweep attack defense is disabled. 2. Run the firewall defend ip-sweep max-rate max-rate-number command to set the IP sweep maximum connection rate. The default maximum connection rate is 4000 pps. 3. Run the firewall defend ip-sweep blacklist-timeout interval command to set the blacklist aging time. By default, the blacklist aging time is 20 minutes. 4. Run the firewall blacklist enable command to enable the blacklist function. After IP sweep attack defense is enabled, the device checks received TCP, UDP, and ICMP packets. If the number of packets that a source address sends per second to different destination IP addresses exceeds the specified threshold, the USG2000&5000 considers that the source address is initiating an IP sweep attack. It blacklists the IP address and: Discards the packets from the source address if the blacklist function is enabled. Forwards the packets from the source address and generates an alarm if the blacklist function is disabled.

Configuration of SIP flood attack defense for the USG2000&5000 series on the CLI
You can configure SIP flood attack defense for the USG2000&5000 series on the CLI. 1. In the user view, run the system-view command to access the system view. 2. Run the firewall defend sip-flood enable command to enable the SIP flood attack defense function. 3. According to the attack defense scope, run either of the following commands to set SIP flood attack parameters: (a) Run the firewall defend sip-flood ip ip-address [ vpn-instance vpn-instance-name ] [ alert-rate alert-rate ] [ max-rate rate-number ] [ source-detect [ on | off ] ] command to set SIP flood attack defense parameters based on IP addresses. The source detection function is enabled by default. (b) Run the firewall defend sip-flood zone [ vpn-instance vpn-instance-name ] zone-name [ alert-rate alert-rate ] [ max-rate rate-number ] [ source-detect [ on | off ] ] command to set SIP flood attack defense parameters based on security zones. The source detection function is enabled by default. 4. Run the firewall defend sip-flood port range [start-port end-port ] command to set a port range for SIP flood attack defense.

Whether the USG2000&5000 supports IP spoofing attack defense
Yes. When the USG2000&5000 works in transparent or multi-egress mode, or policy-based routing is applied, IP spoofing attack defense cannot be configured.

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