Configuring Intrusion Prevention

Impacts on Services

If the Intercept mode is enabled, the IPS function blocks various threats and malicious traffic. To change the protection mode, you are advised to enable the Observe mode and check false alarms for a period of time and then switch to the Intercept mode.

Intrusion Prevention System (IPS)

IPS detects and defends against access traffic in real time based on the attack defense experience and rules accumulated over the years, blocking common network attacks and effectively protecting your assets.

Adjusting the IPS Protection Mode to Block Network Attacks

1. Log in to the management console.
2. Click in the upper left corner of the management console. Select a region.
3. In the navigation pane on the left, click and choose Security & Compliance > Cloud Firewall. The Dashboard page will be displayed.
4. (Optional) Switch to another firewall instance. Select a firewall from the drop-down list in the upper left corner of the page.
5. In the navigation pane, choose Attack Defense > Intrusion Prevention. Enable Basic Protection.
6. Select a protection mode. The Intercept status of a rule varies depending on the protection mode. For details, see Default Actions of Rule Groups in Different Protection Modes. For details about how to modify an IPS rule, see Modifying the Protection Action of an Intrusion Prevention Rule.
   • Observe: Attacks are detected and recorded in logs but are not intercepted.
   • Intercept: Attacks and abnormal IP address access are automatically intercepted.
     • Intercept mode - loose: The protection granularity is coarse. In this mode, only attacks with high threat and high certainty are blocked.
     • Intercept mode - moderate: The protection granularity is medium. This mode meets protection requirements in most scenarios.
     • Intercept mode - strict: The protection granularity is fine-grained, and all attack requests are intercepted.
   

   • You are advised to use the observe mode for a period of time before using the intercept mode. For details about how to view attack event logs, see Attack Event Logs.
   • If a rule blocks normal traffic, you can modify the action of the rule. For details, see IPS Rule Management.

Enabling Sensitive Directory Scan Defense

1. Log in to the management console.
2. Click in the upper left corner of the management console. Select a region.
3. In the navigation pane on the left, click and choose Security & Compliance > Cloud Firewall. The Dashboard page will be displayed.
4. (Optional) Switch to another firewall instance. Select a firewall from the drop-down list in the upper left corner of the page.
5. In the navigation pane, choose Attack Defense > Intrusion Prevention. Enable Basic Protection.
6. Click Advanced. In the Sensitive Directory Scan Defense area, click to enable protection.
   • Action:
     • Observe: Detected sensitive directory scanning attacks are only recorded in attack event logs.
     • Block session: If the firewall detects a sensitive directory scan attack, it blocks the current session.
     • Block IP: If CFW detects a sensitive directory scan attack, it blocks the attack IP address for a period of time.
       

       After Block IP is configured, CFW continuously blocks IP addresses. If address translation or proxy is involved, evaluate the impact of blocking IP addresses with caution.

   • Duration: If Action is set to Block IP, you can set the blocking duration. The value range is 60s to 3,600s.
   • Threshold: CFW performs the specified action if the scan frequency of a sensitive directory reaches this threshold.

Enabling Reverse Shell Defense

1. Log in to the management console.
2. Click in the upper left corner of the management console. Select a region.
3. In the navigation pane on the left, click and choose Security & Compliance > Cloud Firewall. The Dashboard page will be displayed.
4. (Optional) Switch to another firewall instance. Select a firewall from the drop-down list in the upper left corner of the page.
5. In the navigation pane, choose Attack Defense > Intrusion Prevention. Enable Basic Protection.
6. Click Advanced. In the Reverse Shell Defense module, click to enable defense.
   • Action:
     • Observe: Detected reverse shell attacks are only recorded in attack event logs.
     • Block session: If the firewall detects a reverse shell attack, it blocks the current session.
     • Block IP: If CFW detects a reverse shell attack, it blocks the attack IP address for a period of time.
       

       After Block IP is configured, CFW continuously blocks IP addresses. If address translation or proxy is involved, evaluate the impact of blocking IP addresses with caution.

   • Duration: If Action is set to Block IP, you can set the blocking duration. The value range is 60s to 3,600s.
   • Mode:
     • Conservative: coarse-grained protection. If a single session is attacked for four times, observation or interception is triggered. It ensures that no false positives are reported.
     • Sensitive: fine-grained protection. If a single session is attacked for two times, observation or interception is triggered. It ensures that attacks can be detected and handled.

Disabling IPS Basic Protection

• If custom IPS rules have been added, IPS basic protection cannot be disabled.
• If IPS basic protection is disabled, the virtual patch, sensitive directory scan prevention, and reverse shell detection prevention functions will be disabled with it.

1. Log in to the management console.
2. Click in the upper left corner of the management console and select a region or project.
3. (Optional) Switch to another firewall instance. Select a firewall from the drop-down list in the upper left corner of the page.
4. In the navigation pane, choose Attack Defense > Intrusion Prevention.
5. Click next to Basic Protection to disable basic protection.

Follow-up Operations

For details about the protection overview, see Viewing Attack Defense Information on the Dashboard. For details about logs, see Attack Event Logs.

References

For details about how to handle incorrect IPS blocking, see What Do I Do If IPS Blocks Normal Services?