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๐Ÿ›ก๏ธ AWS EC2 Security Group allows unrestricted DNS traffic๐ŸŸข

  • Contextual name: ๐Ÿ›ก๏ธ Security Group allows unrestricted DNS traffic๐ŸŸข
  • ID: /ce/ca/aws/ec2/security-group-allows-unrestricted-dns-traffic
  • Tags:
  • Policy Type: COMPLIANCE_POLICY
  • Policy Categories: SECURITY

Statsโ€‹

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Logicโ€‹

Similar Policiesโ€‹

Similar Internal Rulesโ€‹

RulePoliciesFlags
โœ‰๏ธ dec-x-5dc6b82a1
โœ‰๏ธ dec-x-892f536e1

Descriptionโ€‹

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Descriptionโ€‹

AWS EC2 Security Groups should not allow unrestricted DNS traffic to avoid exposure to security vulnerabilities. Security group rules should be configured to limit DNS traffic (UDP port 53) to trusted IP ranges, such as internal networks or approved DNS servers, reducing the risk of misuse or attacks such as DNS amplification.

Rationaleโ€‹

Restricting DNS traffic prevents unauthorized use of EC2 instances for malicious activities, such as DNS tunneling or participating in amplification attacks. By limiting DNS access to trusted sources, you ensure only authorized clients and servers can interact, reducing the surface area for potential exploits.

Impactโ€‹

Implementing restrictions might cause service interruptions if legitimate applications are not properly configured to use allowed DNS servers, making it essential to validate and update configurations thoroughly during remediation.

Auditโ€‹

This policy marks an EC2 Security Group as INCOMPLIANT if it contains a rule that meets all the following conditions:

... see more

Remediationโ€‹

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Remediationโ€‹

From Command Lineโ€‹

  1. Run the following command to remove or modify the unrestricted rule for DNS access:

    aws ec2 revoke-security-group-ingress \
        --region {{region-name}} \
        --group-id {{security-group-id}} \
        --protocol {{protocol}} \
        --port 53 \
        --cidr {{0.0.0.0/0 or ::/0}}
    • Optionally, run the authorize-security-group-ingress command to create a new rule, specifying a trusted CIDR range instead of 0.0.0.0/0.

  2. Confirm the changes by describing the security group again and ensuring the unrestricted access rule has been removed or appropriately restricted:

    aws ec2 describe-security-groups \
        --region {{region-name}} \
        --group-ids {{security-group-id}} \
        --query 'SecurityGroups[*].IpPermissions[?FromPort==`53`].{CIDR:IpRanges[*].CidrIp,Port:FromPort}'

  3. Test the functionality of services that rely on DNS to ensure that they operate correctly with the updated security group rules.

policy.yamlโ€‹

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Linked Framework Sectionsโ€‹

SectionSub SectionsInternal RulesPoliciesFlagsCompliance
๐Ÿ’ผ APRA CPG 234 โ†’ ๐Ÿ’ผ 36f network design โ€” to ensure authorised network traffic flows and to reduce the impact of security compromises;76107no data
๐Ÿ’ผ APRA CPG 234 โ†’ ๐Ÿ’ผ 45 An understanding of plausible worst case scenarios can help regulated entities identify and implement additional controls to prevent or reduce the impact of such scenarios. One example is malware that infects computers and encrypts data, both on the infected computer and any connected storage, including (corporate) networks and cloud storage. Such attacks reinforce the importance of protecting the backup environment in the event that the production environment is compromised. Common techniques to achieve this include network segmentation, highly restricted and segregated access controls and network traffic flow restrictions.83115no data
๐Ÿ’ผ Cloudaware Framework โ†’ ๐Ÿ’ผ Network Exposure137no data
๐Ÿ’ผ FedRAMP High Security Controls โ†’ ๐Ÿ’ผ AC-3 Access Enforcement (L)(M)(H)49103no data
๐Ÿ’ผ FedRAMP High Security Controls โ†’ ๐Ÿ’ผ AC-4(21) Physical or Logical Separation of Information Flows (M)(H)18141no data
๐Ÿ’ผ FedRAMP High Security Controls โ†’ ๐Ÿ’ผ CM-7(1) Periodic Review (M)(H)1819no data
๐Ÿ’ผ FedRAMP Low Security Controls โ†’ ๐Ÿ’ผ AC-3 Access Enforcement (L)(M)(H)103no data
๐Ÿ’ผ FedRAMP Moderate Security Controls โ†’ ๐Ÿ’ผ AC-3 Access Enforcement (L)(M)(H)103no data
๐Ÿ’ผ FedRAMP Moderate Security Controls โ†’ ๐Ÿ’ผ AC-4(21) Physical or Logical Separation of Information Flows (M)(H)141no data
๐Ÿ’ผ FedRAMP Moderate Security Controls โ†’ ๐Ÿ’ผ CM-7(1) Periodic Review (M)(H)19no data
๐Ÿ’ผ ISO/IEC 27001:2013 โ†’ ๐Ÿ’ผ A.9.1.2 Access to networks and network services2767no data
๐Ÿ’ผ ISO/IEC 27001:2013 โ†’ ๐Ÿ’ผ A.9.4.1 Information access restriction4992no data
๐Ÿ’ผ ISO/IEC 27001:2013 โ†’ ๐Ÿ’ผ A.13.1.1 Network controls65no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ DE.AE-1: A baseline of network operations and expected data flows for users and systems is established and managed1179no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.AC-3: Remote access is managed66no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.AC-4: Access permissions and authorizations are managed, incorporating the principles of least privilege and separation of duties48127no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.AC-5: Network integrity is protected (e.g., network segregation, network segmentation)1184no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.DS-2: Data-in-transit is protected1797no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.DS-5: Protections against data leaks are implemented89152no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.PT-3: The principle of least functionality is incorporated by configuring systems to provide only essential capabilities3179no data
๐Ÿ’ผ NIST CSF v1.1 โ†’ ๐Ÿ’ผ PR.PT-4: Communications and control networks are protected1184no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ ID.AM-03: Representations of the organization's authorized network communication and internal and external network data flows are maintained128no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.AA-03: Users, services, and hardware are authenticated102no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.AA-05: Access permissions, entitlements, and authorizations are defined in a policy, managed, enforced, and reviewed, and incorporate the principles of least privilege and separation of duties199no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.AA-06: Physical access to assets is managed, monitored, and enforced commensurate with risk84no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.DS-01: The confidentiality, integrity, and availability of data-at-rest are protected248no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.DS-02: The confidentiality, integrity, and availability of data-in-transit are protected219no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.DS-10: The confidentiality, integrity, and availability of data-in-use are protected249no data
๐Ÿ’ผ NIST CSF v2.0 โ†’ ๐Ÿ’ผ PR.IR-01: Networks and environments are protected from unauthorized logical access and usage165no data
๐Ÿ’ผ NIST SP 800-53 Revision 5 โ†’ ๐Ÿ’ผ AC-4(21) Information Flow Enforcement _ Physical or Logical Separation of Information Flows83141no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.1 Establish and implement firewall and router configuration standards71110no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.1.6 Documentation of business justification and approval for use of all services, protocols, and ports allowed, including documentation of security features implemented for those protocols considered to be insecure.195no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.2.1 Restrict inbound and outbound traffic to that which is necessary for the cardholder data environment, and specifically deny all other traffic.16111no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.3 Prohibit direct public access between the Internet and any system component in the cardholder data environment.712113no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.3.1 Implement a DMZ to limit inbound traffic to only system components that provide authorized publicly accessible services, protocols, and ports.10100no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.3.2 Limit inbound Internet traffic to IP addresses within the DMZ.100no data
๐Ÿ’ผ PCI DSS v3.2.1 โ†’ ๐Ÿ’ผ 1.3.5 Permit only โ€œestablishedโ€ connections into the network.100no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.2.1 Configuration standards for NSC rulesets are defined, implemented, maintained.105no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.2.5 All services, protocols, and ports allowed are identified, approved, and have a defined business need.95no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.2.6 Security features are defined and implemented for all services, protocols, and ports that are in use and considered to be insecure, such that the risk is mitigated.95no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.3.1 Inbound traffic to the CDE is restricted.111no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.3.2 Outbound traffic from the CDE is restricted.111no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.4.1 NSCs are implemented between trusted and untrusted networks.90no data
๐Ÿ’ผ PCI DSS v4.0.1 โ†’ ๐Ÿ’ผ 1.4.2 Inbound traffic from untrusted networks to trusted networks is restricted.100no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.2.1 Configuration standards for NSC rulesets are defined, implemented, maintained.62105no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.2.5 All services, protocols, and ports allowed are identified, approved, and have a defined business need.4795no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.2.6 Security features are defined and implemented for all services, protocols, and ports that are in use and considered to be insecure, such that the risk is mitigated.2195no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.3.1 Inbound traffic to the CDE is restricted.31111no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.3.2 Outbound traffic from the CDE is restricted.111no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.4.1 NSCs are implemented between trusted and untrusted networks.3190no data
๐Ÿ’ผ PCI DSS v4.0 โ†’ ๐Ÿ’ผ 1.4.2 Inbound traffic from untrusted networks to trusted networks is restricted.31100no data
๐Ÿ’ผ SOC 2 โ†’ ๐Ÿ’ผ CC6.1-7 Restricts Access to Information Assets1867no data
๐Ÿ’ผ SOC 2 โ†’ ๐Ÿ’ผ CC6.6-1 Restricts Access2162no data
๐Ÿ’ผ UK Cyber Essentials โ†’ ๐Ÿ’ผ 1.2 Prevent access to the administrative interface from the internet85119no data