Identifies AWS API activity originating from uncommon desktop client applications based on the user agent string. This rule detects S3 Browser and Cyberduck, which are graphical S3 management tools that provide bulk upload/download capabilities. While legitimate, these tools are rarely used in enterprise environments and have been observed in use by threat actors for data exfiltration. Any activity from these clients should be validated against authorized data transfer workflows.

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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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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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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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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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Identifies multiple AWS Bedrock executions in a one minute time window without guardrails by the same user in the same account over a session. Multiple consecutive executions implies that a user may be intentionally attempting to bypass security controls, by not routing the requests with the desired guardrail configuration in order to access sensitive information, or possibly exploit a vulnerability in the system.

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Detects when a single AWS resource is running multiple read-only, discovery API calls in a 10-second window. This behavior could indicate an actor attempting to discover the AWS infrastructure 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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Identifies when an AWS DynamoDB table is exported to S3. Adversaries may use the ExportTableToPointInTime operation to collect sensitive information or exfiltrate data from DynamoDB tables. This rule detects unusual user activity by monitoring for the ExportTableToPointInTime action in CloudTrail logs. This is a New Terms rule that only flags when this behavior is observed by a user or role for the first time.

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Detects a principal modifying an S3 bucket ACL to grant public read or write access that has not been observed doing so within the history window, using canned ACLs such as public-read or public-read-write. ACL-based public access is a distinct API path (PutBucketAcl) that can bypass some Block Public Access controls. Monitoring for new identities performing this change helps surface freshly compromised credentials being used to stage data for exfiltration or inadvertently expose sensitive content.

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Identifies the deletion of critical Amazon S3 bucket configurations such as bucket policies, lifecycle configurations or encryption settings. These actions are typically administrative but may also represent adversarial attempts to remove security controls, disable data retention mechanisms, or conceal evidence of malicious activity. Adversaries who gain access to AWS credentials may delete logging, lifecycle, or policy configurations to disrupt forensic visibility and inhibit recovery. For example, deleting a bucket policy can open a bucket to public access or remove protective access restrictions, while deleting lifecycle rules can prevent object archival or automatic backups. Such actions often precede data exfiltration or destructive operations and should be reviewed in context with related S3 or IAM events.

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Identifies a high number of failed S3 operations against a single bucket from a single source address within a short timeframe. This activity can indicate attempts to collect bucket objects or cause an increase in billing to an account via internal "AccessDenied" errors.

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Identifies the addition of an expiration lifecycle configuration to an Amazon S3 bucket. S3 lifecycle rules can automatically delete or transition objects after a defined period. Adversaries can abuse them by configuring auto-deletion of logs, forensic evidence, or sensitive objects to cover their tracks. This rule detects the use of the PutBucketLifecycle or PutBucketLifecycleConfiguration APIs with Expiration parameters, which may indicate an attempt to automate the removal of data to hinder investigation or maintain operational secrecy after malicious activity.

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Detects when MFA Delete is disabled on an Amazon S3 bucket. MFA Delete is an additional layer of security for versioned S3 buckets that requires multi-factor authentication to permanently delete object versions or disable versioning. When MFA Delete is disabled, an adversary with S3 write access and a compromised long-term access key can permanently delete object versions, a critical step in ransomware attacks that target S3 versioning as a backup mechanism. MFA Delete is configured via PutBucketVersioning with the MfaDelete parameter set to Disabled.

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Detects when an Amazon S3 bucket policy is modified to grant public access using a wildcard (Principal:"") statement. This rule analyzes PutBucketPolicy events that include both Effect=Allow and Principal:"" in the request parameters, indicating that permissions were extended to all identities, potentially making the bucket or its contents publicly accessible. Publicly exposing an S3 bucket is one of the most common causes of sensitive data leaks in AWS environments. Adversaries or misconfigurations can leverage this exposure to exfiltrate data, host malicious content, or collect credentials and logs left in open storage.

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Detects when an Amazon S3 bucket policy is modified to share access with an external AWS account. This rule analyzes PutBucketPolicy events and compares the S3 bucket’s account ID to any account IDs referenced in the policy’s Effect=Allow statements. If the policy includes principals from accounts other than the bucket owner’s, the rule triggers an alert. This behavior may indicate an adversary backdooring a bucket for data exfiltration or cross-account persistence. For example, an attacker who compromises credentials could attach a policy allowing access from an external AWS account they control, enabling continued access even after credentials are rotated. Note: This rule will not alert if the account ID is part of the bucket’s name or appears in the resource ARN. Such cases are common in standardized naming conventions (e.g., “mybucket-123456789012”). To ensure full coverage, use complementary rules to monitor for suspicious PutBucketPolicy API requests targeting buckets with account IDs embedded in their names or resources.

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Identifies the creation or modification of an S3 bucket replication configuration that sends data to a bucket in a different AWS account. Cross-account replication can be used legitimately for backup, disaster recovery, and multi-account architectures, but adversaries with write access to an S3 bucket may abuse replication rules to silently exfiltrate large volumes of data to attacker-controlled accounts. This rule detects "PutBucketReplication" events where the configured destination account differs from the source bucket's account, indicating potential unauthorized cross-account data movement.

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Identifies when server access logging is disabled for an Amazon S3 bucket. Server access logs provide a detailed record of requests made to an S3 bucket. When server access logging is disabled for a bucket, it could indicate an adversary's attempt to impair defenses by disabling logs that contain evidence of malicious activity.

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Detects successful S3 GetObject calls targeting high-value credential and secret files commonly stored in S3 buckets: AWS credentials files (".aws/credentials", ".aws/config"), SSH private keys ("id_rsa", "id_ed25519", "id_ecdsa", "id_dsa"), environment files (".env"), PEM and PuTTY key files, and other private key patterns. These file types are high-yield targets for credential harvesting from S3. The rule excludes AWSService identity type to suppress S3 replication, Glacier restore, and other AWS-internal data movement that legitimately reads these files.

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Identifies use of the S3 CopyObject API where the destination object is encrypted using an AWS KMS key from an external AWS account. This behavior may indicate ransomware-style impact activity where an adversary with access to a misconfigured S3 bucket encrypts objects using a KMS key they control, preventing the bucket owner from decrypting their own data. This technique is a critical early signal of destructive intent or cross-account misuse.

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Identifies when object versioning is suspended for an Amazon S3 bucket. Object versioning allows for multiple versions of an object to exist in the same bucket. This allows for easy recovery of deleted or overwritten objects. When object versioning is suspended for a bucket, it could indicate an adversary's attempt to inhibit system recovery following malicious activity. Additionally, when versioning is suspended, buckets can then be deleted.

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Identifies when the same AWS principal, from the same source IP, successfully invokes read-only S3 control-plane APIs that reveal bucket posture across many buckets in a short period. This pattern can indicate automated reconnaissance or security scanning, similar to CSPM tools and post-compromise enumeration. The rule excludes AWS service principals, requires programmatic-style sessions (not Management Console credentials), and requires populated resource and identity fields so nulls do not skew cardinality.

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This rule detects when a JavaScript file is uploaded in an S3 static site directory (static/js/) by an IAM user or assumed role. This can indicate suspicious modification of web content hosted on S3, such as injecting malicious scripts into a static website frontend.

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Identifies AWS CloudTrail events where an unauthenticated source is attempting to access an S3 bucket. This activity may indicate a misconfigured S3 bucket policy that allows public access to the bucket, potentially exposing sensitive data to unauthorized users. Adversaries can specify --no-sign-request in the AWS CLI to retrieve objects from an S3 bucket without authentication. This is a New Terms rule, which means it will trigger for each unique combination of the source.address and targeted bucket name that has not been seen making this API request.

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Identifies a high-volume of AWS S3 objects stored in a bucket using using Server-Side Encryption with Customer-Provided Keys (SSE-C). Adversaries with compromised AWS credentials can encrypt objects in an S3 bucket using their own encryption keys, rendering the objects unreadable or recoverable without the key. This can be used as a form of ransomware to extort the bucket owner for the decryption key. This is a Threshold rule that triggers when this behavior is observed multiple times for a specific bucket in a short time-window.

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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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Identifies potential ransomware note being uploaded to an AWS S3 bucket. This rule detects the PutObject S3 API call with an object name commonly associated with ransomware notes. The keywords detected here rarely overlap with common file names and have been attributed to ransomware notes with high-confidence. Adversaries with access to a misconfigured S3 bucket may retrieve, delete, and replace objects with ransom notes to extort victims.

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Identifies when AWS S3 objects stored in a bucket are encrypted using Server-Side Encryption with Customer-Provided Keys (SSE-C). Adversaries with compromised AWS credentials can encrypt objects in an S3 bucket using their own encryption keys, rendering the objects unreadable or recoverable without the key. This can be used as a form of ransomware to extort the bucket owner for the decryption key. This is a New Terms rule that flags when this behavior is observed for the first time user and target bucket name.

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Detects repeated high-confidence 'BLOCKED' actions coupled with specific 'Content Filter' policy violation having codes such as 'MISCONDUCT', 'HATE', 'SEXUAL', INSULTS', 'PROMPT_ATTACK', 'VIOLENCE' indicating persistent misuse or attempts to probe the model's ethical boundaries.

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Detects repeated compliance violation 'BLOCKED' actions coupled with specific policy name such as 'sensitive_information_policy', indicating persistent misuse or attempts to probe the model's denied topics.

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Detects repeated compliance violation 'BLOCKED' actions coupled with specific policy name such as 'topic_policy', indicating persistent misuse or attempts to probe the model's denied topics.

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Detects repeated compliance violation 'BLOCKED' actions coupled with specific policy name such as 'word_policy', indicating persistent misuse or attempts to probe the model's denied topics.

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