Update v8.13.19

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This section lists all updates associated with version 8.13.19 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

Potential Widespread Malware Infection Across Multiple Hosts

This rule uses alert data to determine when a malware signature is triggered in multiple hosts. Analysts can use this to prioritize triage and response, as this can potentially indicate a widespread malware infection.

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AWS EC2 Multi-Region DescribeInstances API Calls

Identifies when a single AWS resource is making DescribeInstances API calls in more than 10 regions within a 30-second window. This could indicate a potential threat actor attempting to discover the AWS infrastructure across multiple regions using compromised credentials or a compromised instance. Adversaries may use this information to identify potential targets for further exploitation or to gain a better understanding of the target’s infrastructure.

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AWS Service Quotas Multi-Region GetServiceQuota Requests

Identifies when a single AWS resource is making GetServiceQuota API calls for the EC2 service quota L-1216C47A in more than 10 regions within a 30-second window. Quota code L-1216C47A represents on-demand instances which are used by adversaries to deploy malware and mine cryptocurrency. This could indicate a potential threat actor attempting to discover the AWS infrastructure across multiple regions using compromised credentials or a compromised instance.

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AWS EC2 EBS Snapshot Shared with Another Account

Identifies AWS EC2 EBS snaphots being shared with another AWS account. EBS virtual disks can be copied into snapshots, which can then be shared with an external AWS account or made public. Adversaries may attempt this in order to copy the snapshot into an environment they control, to access the data.

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AWS S3 Bucket Enumeration or Brute Force

Identifies a high number of failed S3 operations from a single source and account (or anonymous account) within a short timeframe. This activity can be indicative of attempting to cause an increase in billing to an account for excessive random operations, cause resource exhaustion, or enumerating bucket names for discovery.

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Potential AWS S3 Bucket Ransomware Note Uploaded

Identifies potential ransomware note being uploaded to an AWS S3 bucket. This rule detects the PutObject S3 API call with a common ransomware note file extension such as .ransom, or .lock. Adversaries with access to a misconfigured S3 bucket may retrieve, delete, and replace objects with ransom notes to extort victims.

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AWS S3 Object Encryption Using External KMS Key

Identifies CopyObject events within an S3 bucket using an AWS KMS key from an external account for encryption. Adversaries with access to a misconfigured S3 bucket and the proper permissions may encrypt objects with an external KMS key to deny their victims access to their own data.

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AWS Signin Single Factor Console Login with Federated User

Identifies when a federated user logs into the AWS Management Console without using multi-factor authentication (MFA). Federated users are typically given temporary credentials to access AWS services. If a federated user logs into the AWS Management Console without using MFA, it may indicate a security risk, as MFA adds an additional layer of security to the authentication process. This could also indicate the abuse of STS tokens to bypass MFA requirements.

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AWS IAM User Created Access Keys For Another User

An adversary with access to a set of compromised credentials may attempt to persist or escalate privileges by creating a new set of credentials for an existing user. This rule looks for use of the IAM CreateAccessKey API operation to create new programmatic access keys for another IAM user.

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AWS IAM AdministratorAccess Policy Attached to Group

An adversary with access to a set of compromised credentials may attempt to persist or escalate privileges by attaching additional permissions to user groups the compromised user account belongs to. This rule looks for use of the IAM AttachGroupPolicy API operation to attach the highly permissive AdministratorAccess AWS managed policy to an existing IAM user group.

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AWS IAM AdministratorAccess Policy Attached to Role

An adversary with access to a set of compromised credentials may attempt to persist or escalate privileges by attaching additional permissions to compromised IAM roles. This rule looks for use of the IAM AttachRolePolicy API operation to attach the highly permissive AdministratorAccess AWS managed policy to an existing IAM role.

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AWS IAM AdministratorAccess Policy Attached to User

An adversary with access to a set of compromised credentials may attempt to persist or escalate privileges by attaching additional permissions to compromised user accounts. This rule looks for use of the IAM AttachUserPolicy API operation to attach the highly permissive AdministratorAccess AWS managed policy to an existing IAM user.

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AWS Bedrock Guardrails Detected Multiple Violations by a Single User Over a Session

Identifies multiple violations of AWS Bedrock guardrails by the same user in the same account over a session. Multiple violations implies that a user may be intentionally attempting to cirvumvent security controls, access sensitive information, or possibly exploit a vulnerability in the system.

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AWS Bedrock Guardrails Detected Multiple Policy Violations Within a Single Blocked Request

Identifies multiple violations of AWS Bedrock guardrails within a single request, resulting in a block action, increasing the likelihood of malicious intent. Multiple violations implies that a user may be intentionally attempting to cirvumvent security controls, access sensitive information, or possibly exploit a vulnerability in the system.

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Unusual High Confidence Misconduct Blocks Detected

Detects repeated high-confidence BLOCKED actions coupled with specific violation codes such as MISCONDUCT, indicating persistent misuse or attempts to probe the model’s ethical boundaries.

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Potential Abuse of Resources by High Token Count and Large Response Sizes

Detects potential resource exhaustion or data breach attempts by monitoring for users who consistently generate high input token counts, submit numerous requests, and receive large responses. This behavior could indicate an attempt to overload the system or extract an unusually large amount of data, possibly revealing sensitive information or causing service disruptions.

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AWS Bedrock Detected Multiple Attempts to use Denied Models by a Single User

Identifies multiple successive failed attempts to use denied model resources within AWS Bedrock. This could indicated attempts to bypass limitations of other approved models, or to force an impact on the environment by incurring exhorbitant costs.

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AWS Bedrock Detected Multiple Validation Exception Errors by a Single User

Identifies multiple validation exeception errors within AWS Bedrock. Validation errors occur when you run the InvokeModel or InvokeModelWithResponseStream APIs on a foundation model that uses an incorrect inference parameter or corresponding value. These errors also occur when you use an inference parameter for one model with a model that doesn’t have the same API parameter. This could indicate attempts to bypass limitations of other approved models, or to force an impact on the environment by incurring exhorbitant costs.

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Azure Entra Sign-in Brute Force against Microsoft 365 Accounts

Identifies potential brute-force attempts against Microsoft 365 user accounts by detecting a high number of failed interactive or non-interactive login attempts within a 30-minute window. Attackers may attempt to brute force user accounts to gain unauthorized access to Microsoft 365 services via different services such as Exchange, SharePoint, or Teams.

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Azure Entra Sign-in Brute Force Microsoft 365 Accounts by Repeat Source

Identifies potential brute-force attempts against Microsoft 365 user accounts by detecting a high number of failed interactive or non-interactive login attempts within a 30-minute window from a single source. Attackers may attempt to brute force user accounts to gain unauthorized access to Microsoft 365 services via different services such as Exchange, SharePoint, or Teams.

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Attempts to Brute Force a Microsoft 365 User Account

Identifies potential brute-force attempts against Microsoft 365 user accounts by detecting a high number of failed login attempts or login sources within a 30-minute window. Attackers may attempt to brute force user accounts to gain unauthorized access to Microsoft 365 services.

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Multiple Device Token Hashes for Single Okta Session

This rule detects when a specific Okta actor has multiple device token hashes for a single Okta session. This may indicate an authenticated session has been hijacked or is being used by multiple devices. Adversaries may hijack a session to gain unauthorized access to Okta admin console, applications, tenants, or other resources.

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Multiple Okta User Authentication Events with Client Address

Detects when a certain threshold of Okta user authentication events are reported for multiple users from the same client address. Adversaries may attempt to launch a credential stuffing or password spraying attack from the same device by using a list of known usernames and passwords to gain unauthorized access to user accounts.

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Multiple Okta User Authentication Events with Same Device Token Hash

Detects when a high number of Okta user authentication events are reported for multiple users in a short time frame. Adversaries may attempt to launch a credential stuffing or password spraying attack from the same device by using a list of known usernames and passwords to gain unauthorized access to user accounts.

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High Number of Okta Device Token Cookies Generated for Authentication

Detects when an Okta client address has a certain threshold of Okta user authentication events with multiple device token hashes generated for single user authentication. Adversaries may attempt to launch a credential stuffing or password spraying attack from the same device by using a list of known usernames and passwords to gain unauthorized access to user accounts.

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Okta User Sessions Started from Different Geolocations

Detects when a specific Okta actor has multiple sessions started from different geolocations. Adversaries may attempt to launch an attack by using a list of known usernames and passwords to gain unauthorized access to user accounts from different locations.

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Successful Application SSO from Rare Unknown Client Device

Detects successful single sign-on (SSO) events to Okta applications from an unrecognized or "unknown" client device, as identified by the user-agent string. This activity may be indicative of exploitation of a vulnerability in Okta’s Classic Engine, which could allow an attacker to bypass application-specific sign-on policies, such as device or network restrictions. The vulnerability potentially enables unauthorized access to applications using only valid, stolen credentials, without requiring additional authentication factors.

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