S3 Bucket Encryption Deleted

Status: Experimental
Severity: medium
Log types: AWS.CloudTrail
Tags: AWS, S3, Defense Evasion, Impact:Data Destruction
Reference: https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucket-encryption.html
Source: github.com/panther-labs/panther-analysis

Detects when S3 bucket encryption configuration is deleted, which could expose data to unauthorized access or indicate ransomware preparation activity.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1562` Impair Defenses
Impact	`T1485` Data Destruction

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

AWS S3 Bucket Configuration Deletion (Elastic)

Rule body yaml

AnalysisType: rule
Filename: aws_s3_delete_bucket_encryption.py
RuleID: "AWS.S3.DeleteBucketEncryption"
DisplayName: "S3 Bucket Encryption Deleted"
Enabled: true
LogTypes:
  - AWS.CloudTrail
Tags:
  - AWS
  - S3
  - Defense Evasion
  - Impact:Data Destruction
Reports:
  MITRE ATT&CK:
    - TA0005:T1562
    - TA0040:T1485
Severity: Medium
Status: Experimental
Description: Detects when S3 bucket encryption configuration is deleted, which could expose data to unauthorized access or indicate ransomware preparation activity.
Runbook: |
  1. Query CloudTrail for all S3 API calls by the userIdentity:arn on the requestParameters:bucketName in the 24 hours before and after the encryption deletion to identify if this is part of a larger attack pattern
  2. Check if this user has performed DeleteBucketEncryption on this bucket in the past 90 days to determine if this is normal administrative activity
  3. Find other alerts with rule IDs AWS.S3.DisableBucketLogging, AWS.S3.SuspendVersioning, or AWS.S3.DisableMfaDelete for the same bucket in the past 7 days to detect coordinated security control disabling
Reference: https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucket-encryption.html
SummaryAttributes:
  - sourceIpAddress
  - userAgent
  - recipientAccountId
  - p_any_aws_arns
Tests:
  - Name: Bucket Encryption Deleted Successfully
    ExpectedResult: true
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "AssumedRole",
            "principalId": "AAAAAAAAAAAAAAAAAAAAA:user_name",
            "arn": "arn:aws:sts::111111111111:assumed-role/sample-role-dreamy-yonath/sample-role-brave-yalow-role-intelligent-brahmagupta-role-beautiful-keldysh-role-happy-easley-role-bold-buck",
            "accountId": "111111111111",
            "accessKeyId": "ASIA-MOCKACCESSKEYID-1",
            "sessionContext":
              {
                "attributes":
                  {
                    "mfaAuthenticated": "false",
                    "creationDate": "2024-01-15T10:30:00Z",
                  },
                "sessionIssuer":
                  {
                    "type": "Role",
                    "principalId": "AAAAAAAAAAAAAAAAAAAAA",
                    "arn": "arn:aws:iam::111111111111:role/sample-role-dreamy-yonath",
                    "accountId": "111111111111",
                    "userName": "AdminRole",
                  },
              },
          },
        "eventTime": "2024-01-15T10:45:23Z",
        "eventSource": "s3.amazonaws.com",
        "eventName": "DeleteBucketEncryption",
        "awsRegion": "us-east-1",
        "sourceIPAddress": "1.2.3.4",
        "userAgent": "aws-cli/2.13.0 Python/3.11.4 Linux/5.10.0-1234-aws exe/x86_64.ubuntu.22",
        "requestParameters":
          {
            "bucketName": "sensitive-data-bucket",
            "host": "sample-bucket-pensive-jones.s3.amazonaws.com",
            "encryption": "",
          },
        "responseElements": null,
        "requestID": "ABC123DEF456",
        "eventID": "12345678-1234-1234-1234-111111111111",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "111111111111",
        "vpcEndpointId": "vpce-1a2b3c4d",
      }
  - Name: Bucket Encryption Deletion Failed
    ExpectedResult: false
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "IAMUser",
            "principalId": "AIDAI23HXS4EXAMPLE",
            "arn": "arn:aws:iam::111111111111:user/testuser",
            "accountId": "111111111111",
            "accessKeyId": "AKIA-MOCKACCESSKEYID-1",
          },
        "eventTime": "2024-01-15T10:45:23Z",
        "eventSource": "s3.amazonaws.com",
        "eventName": "DeleteBucketEncryption",
        "awsRegion": "us-east-1",
        "sourceIPAddress": "1.2.3.4",
        "userAgent": "aws-cli/2.13.0 Python/3.11.4 Linux/5.10.0-1234-aws exe/x86_64.ubuntu.22",
        "errorCode": "AccessDenied",
        "errorMessage": "Access Denied",
        "requestParameters":
          {
            "bucketName": "sensitive-data-bucket",
            "host": "sample-bucket-pensive-jones.s3.amazonaws.com",
          },
        "responseElements": null,
        "requestID": "ABC123DEF456",
        "eventID": "12345678-1234-1234-1234-111111111111",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "111111111111",
      }
  - Name: Different S3 Event
    ExpectedResult: false
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "AssumedRole",
            "principalId": "AAAAAAAAAAAAAAAAAAAAA:user_name",
            "arn": "arn:aws:sts::111111111111:assumed-role/sample-role-dreamy-yonath/sample-role-brave-yalow-role-intelligent-brahmagupta-role-beautiful-keldysh-role-happy-easley-role-bold-buck",
            "accountId": "111111111111",
            "accessKeyId": "ASIA-MOCKACCESSKEYID-1",
          },
        "eventTime": "2024-01-15T10:45:23Z",
        "eventSource": "s3.amazonaws.com",
        "eventName": "PutBucketEncryption",
        "awsRegion": "us-east-1",
        "sourceIPAddress": "1.2.3.4",
        "userAgent": "aws-cli/2.13.0 Python/3.11.4 Linux/5.10.0-1234-aws exe/x86_64.ubuntu.22",
        "requestParameters":
          {
            "bucketName": "sensitive-data-bucket",
            "host": "sample-bucket-pensive-jones.s3.amazonaws.com",
          },
        "responseElements": null,
        "requestID": "ABC123DEF456",
        "eventID": "12345678-1234-1234-1234-111111111111",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "111111111111",
      }
  - Name: Non-S3 Event
    ExpectedResult: false
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "AssumedRole",
            "principalId": "AAAAAAAAAAAAAAAAAAAAA:user_name",
            "arn": "arn:aws:sts::123456789012:assumed-role/AdminRole/user_name",
            "accountId": "123456789012",
            "accessKeyId": "ASIAIOSFODNN7EXAMPLE",
          },
        "eventTime": "2024-01-15T10:45:23Z",
        "eventSource": "ec2.amazonaws.com",
        "eventName": "DeleteBucketEncryption",
        "awsRegion": "us-east-1",
        "sourceIPAddress": "203.0.113.42",
        "userAgent": "aws-cli/2.13.0 Python/3.11.4 Linux/5.10.0-1234-aws exe/x86_64.ubuntu.22",
        "requestParameters": {},
        "responseElements": null,
        "requestID": "ABC123DEF456",
        "eventID": "12345678-1234-1234-1234-123456789012",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "123456789012",
      }

Detection logic

Condition

not (errorCode is_not_null or errorMessage is_not_null)
eventSource eq "s3.amazonaws.com"
eventName eq "DeleteBucketEncryption"

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`errorCode`	is_not_null	(no value, null check)
`errorMessage`	is_not_null	(no value, null check)

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`eventName`	eq	`DeleteBucketEncryption`
`eventSource`	eq	`s3.amazonaws.com`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`eventName`
`eventSource`
`awsRegion`
`recipientAccountId`
`sourceIPAddress`
`userAgent`
`userIdentity`
`actor_user`
`bucketName`	`requestParameters.bucketName`

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`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
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