https://feed.craftedsignal.io/products/splunk-add-on-for-amazon-web-services/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioWed, 03 Jan 2024 12:00:00 +0000https://feed.craftedsignal.io/briefs/2024-01-aws-cloudtrail-update/Wed, 03 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-aws-cloudtrail-update/Attackers may attempt to evade detection by altering CloudTrail logging configurations, such as changing multi-regional logging to a single region, which impairs the logging of their activities and hinders incident response.This detection focuses on identifying attempts to evade detection within AWS environments by monitoring UpdateTrail events in AWS CloudTrail logs. Attackers may modify CloudTrail settings with incorrect parameters, such as switching from multi-regional logging to single-region logging, to reduce the scope of logged activities. This tactic allows adversaries to operate undetected in compromised AWS environments, as their actions in other regions are not properly recorded. Detecting these configuration changes is critical for Security Operations Centers (SOCs) to maintain visibility and respond effectively to threats. The lack of comprehensive logging can significantly impede incident response and forensic investigations, allowing malicious activities to persist unnoticed.

Attack Chain

1. An attacker gains initial access to an AWS account, potentially through compromised credentials or an exposed API key (T1078).
2. The attacker authenticates to the AWS Management Console or uses the AWS CLI with the compromised credentials.
3. The attacker issues an UpdateTrail API call to modify the CloudTrail configuration (T1562.008).
4. The attacker disables multi-region logging, restricting log collection to a single AWS region.
5. Alternatively, the attacker modifies the S3 bucket used for log storage, potentially directing logs to an attacker-controlled location.
6. The attacker performs malicious activities within the AWS environment, knowing that these actions will not be comprehensively logged across all regions.
7. These malicious activities could include lateral movement, data exfiltration, or resource compromise.
8. The reduced logging scope hinders detection and response efforts, allowing the attacker to maintain persistence and achieve their objectives.

Impact

Successful evasion of CloudTrail logging can lead to significant blind spots in security monitoring. If an attacker successfully modifies CloudTrail settings, their subsequent actions within the AWS environment are less likely to be detected. This can lead to prolonged dwell time, increased data exfiltration, and greater overall damage. Organizations relying on CloudTrail for compliance and security auditing may also face regulatory repercussions due to incomplete logging. The blast radius of a successful attack expands significantly when logging is impaired, affecting potentially all resources within the AWS environment.

Recommendation

• Deploy the provided Sigma rule to your SIEM and tune it for your specific AWS environment to detect unauthorized CloudTrail modifications.
• Investigate any UpdateTrail events where the actor.user.uid is not a known administrator account (see Sigma rule below).
• Monitor CloudTrail logs for changes to multi-region logging settings and S3 bucket destinations (see references to api.operation=UpdateTrail in the search field).
• Implement multi-factor authentication (MFA) for all AWS accounts, especially those with administrative privileges to mitigate credential compromise (T1110).
• Regularly review and audit CloudTrail configurations to ensure they align with security best practices and organizational policies.

]]>mediumadvisoryawscloudtraildefense-evasioncloudhttps://feed.craftedsignal.io/briefs/2024-01-aws-nacls-all-open/Wed, 03 Jan 2024 10:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-aws-nacls-all-open/The analytic detects the creation or replacement of AWS Network Access Control Lists (ACLs) with rules that allow all traffic from a specified CIDR block, potentially exposing the network to unauthorized access and increasing the risk of data breaches.This detection focuses on identifying misconfigured AWS Network ACLs (NACLs) that permit unrestricted traffic. AWS NACLs act as a firewall for controlling traffic in and out of subnets within a Virtual Private Cloud (VPC). When an NACL is configured to allow all ports and protocols from any IP address (0.0.0.0/0), it effectively bypasses security controls and exposes resources to potential threats. The activity is detected by monitoring AWS CloudTrail events for CreateNetworkAclEntry or ReplaceNetworkAclEntry API calls. This configuration error can be introduced by administrators during initial setup or through misconfiguration during updates. Defenders should ensure that NACLs follow the principle of least privilege to limit the attack surface.

Attack Chain

1. An attacker identifies a target AWS environment.
2. The attacker scans for publicly accessible services or resources.
3. An administrator, either maliciously or accidentally, creates or modifies a Network ACL using the AWS Management Console, CLI, or API with overly permissive rules (allowing all traffic: ruleAction=allow AND egress=false AND aclProtocol=-1 AND cidrBlock=0.0.0.0/0).
4. The misconfigured NACL is applied to one or more subnets within the VPC.
5. The attacker exploits the open ports and protocols to gain unauthorized access.
6. The attacker attempts to move laterally within the AWS environment.
7. The attacker exfiltrates sensitive data or disrupts services.

Impact

A misconfigured Network ACL that allows all traffic can have severe consequences. It can lead to unauthorized access to sensitive data, potential data breaches, service disruption, and further compromise of the AWS environment. The impact is particularly high if critical resources are located within the affected subnets. This type of misconfiguration violates security best practices and compliance requirements.

Recommendation

• Deploy the Sigma rule AWS Network ACL Created with All Ports Open to your SIEM to detect this specific misconfiguration (logsource: ASL AWS CloudTrail, category: network_connection).
• Review existing Network ACL configurations to identify and remediate any overly permissive rules (check AWS console or use AWS CLI/API).
• Implement automated checks to validate Network ACL configurations against security best practices.
• Ensure that NACLs follow the principle of least privilege by only allowing necessary traffic (review NACL ruleAction, egress, aclProtocol, and cidrBlock settings in CloudTrail logs).
• Investigate any identified instances of overly permissive NACL configurations to determine the root cause and potential impact (analyze CloudTrail logs for CreateNetworkAclEntry or ReplaceNetworkAclEntry events).

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