Ensure that UDP Port Access from the Internet is Evaluated and Restricted

高级别 1人工审核azure

说明

Network security groups should be periodically evaluated for port misconfigurations. Where UDP is not explicitly required and narrowly configured for resources attached to a network security group, Internet-level access to Azure resources should be restricted or eliminated. The potential security problem with broadly exposing UDP services over the Internet is that attackers can use DDoS amplification techniques to reflect spoofed UDP traffic from Azure Virtual Machines. The most common types of these attacks exploit exposed DNS, NTP, SSDP, SNMP, CLDAP, and other UDP-based services as amplification sources to disrupt services on other machines within the Azure Virtual Network, or even attack networked devices outside of Azure.

检查方式

审计方法: 人工审核

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Audit from Azure Portal 1. Go to Network security groups. 2. Click the name of a network security group. 3. Under Settings, click Inbound security rules. 4. Ensure that no inbound security rule exists that matches the following: o Port: 53, 123, 161, 389, or 1900, or range including 53, 123, 161, 389, or 1900. o Protocol: UDP or Any o Source: 0.0.0.0/0, Internet, or Any o Action: Allow 5. Repeat steps 1-4 for each network security group. To audit from Azure Resource Graph: 1. Go to Resource Graph Explorer. 2. Click New query. 3. Paste the following into the query window: resources | where type =~ "microsoft.network/networksecuritygroups" | project id, name, securityRule = properties.securityRules | mv-expand securityRule | extend access = securityRule.properties.access, direction = securityRule.properties.direction, protocol = securityRule.properties.protocol, destinationPort = case(isempty(securityRule.properties.destinationPortRange), securityRule.properties.destinationPortRanges, securityRule.properties.destinationPortRange), sourceAddress = case(isempty(securityRule.properties.sourceAddressPrefix), securityRule.properties.sourceAddressPrefixes, securityRule.properties.source...

修复方式

修复方法: 操作指南或基础设施补丁

Remediate from Azure Portal 1. Go to Network security groups. 2. Click the name of a network security group. 3. Under Settings, click Inbound security rules. 4. Check the box next to any inbound security rule matching: o Port: Port: 53, 123, 161, 389, or 1900, or range including 53, 123, 161, 389, or 1900. o Protocol: UDP or Any o Source: 0.0.0.0/0, Internet, or Any o Action: Allow 5. Click Delete. 6. Click Yes. 7. Repeat steps 1-6 for each network security group requiring remediation. Remediate from Azure CLI For each network security group rule requiring remediation, run the following command to delete the rule: az network nsg rule delete --resource-group <resource-group> --nsg-name <network-security-group> --name <rule>

属性

操作系统: 任意
标签: access-controlazurecloud
参考: CIS Microsoft Azure Foundations Benchmark v6.0.0 - 7.3 Ensure that UDP Port Access from the Internet is Evaluated and Restricted