Decoy S3 Accessed

Severity: high
Entities: actor_ids, aws_account_ids, aws_arns, ip_addresses, trace_ids, usernames
Log types: AWS.SecurityFindingFormat
Reference: https://aws.amazon.com/blogs/security/how-to-detect-suspicious-activity-in-your-aws-account-by-using-private-decoy-resources/
Source: github.com/panther-labs/panther-analysis

Actor accessed S3 Manager decoy secret

Rule body yaml

AnalysisType: rule
Filename: decoy_s3_accessed.py
RuleID: "Decoy.S3.Accessed"
DisplayName: "Decoy S3 Accessed"
Enabled: false
LogTypes:
    - AWS.SecurityFindingFormat
Severity: High
Description: Actor accessed S3 Manager decoy secret
DedupPeriodMinutes: 60
Threshold: 1
Reference: https://aws.amazon.com/blogs/security/how-to-detect-suspicious-activity-in-your-aws-account-by-using-private-decoy-resources/
InlineFilters:
    - All: []
Tests:
    - Name: S3-Decoy-Accessed
      ExpectedResult: true
      Log:
        Action:
            ActionType: AWS_API_CALL
            AwsApiCallAction:
                Api: GetObject
                CallerType: remoteIp
                DomainDetails: {}
                RemoteIpDetails:
                    City: {}
                    Country: {}
                    GeoLocation: {}
                    IpAddressV4: 111.111.111.111
                    Organization: {}
                ServiceName: s3.amazonaws.com
            DnsRequestAction: {}
            NetworkConnectionAction:
                LocalPortDetails: {}
                RemotePortDetails: {}
            PortProbeAction: {}
        AwsAccountId: "123456789012"
        CompanyName: Custom
        CreatedAt: "2024-05-24 00:26:57.000000000"
        Description: Private decoy S3 bucket panther-databucket was accessed by arn:aws:iam::123456789012:user/tester. This S3 bucket has been provisioned to monitor and generate security events when accessed and can be an indicator of unintended or unauthorized access to your AWS Account.
        FindingProviderFields:
            Severity:
                Label: HIGH
                Normalized: 70
            Types:
                - Unusual Behaviors
        GeneratorId: s3.amazonaws.com
        Id: ABC9ONWNS3155VIEJC8U
        ProcessedAt: "2024-05-24T00:27:12.237Z"
        ProductArn: arn:aws:securityhub:us-east-1:123456789012:product/123456789012/default
        ProductFields:
            Custom/DecoyDetector/apiResult: SUCCESS
            Custom/DecoyDetector/requestID: ab1cd234-1986-4c45-8546-fdb1776e23b0
            Custom/DecoyDetector/userAgent: '[Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36]'
            aws/securityhub/CompanyName: Personal
            aws/securityhub/FindingId: arn:aws:service:region:123456789012:resource/12345ab6-436d-4d59-ac58-ed6b3127e440
            aws/securityhub/ProductName: Default
        ProductName: DecoyDetector
        RecordState: ACTIVE
        Region: us-east-1
        Resources:
            - Id: arn:aws:s3:::panther-databucket
              Partition: aws
              Region: us-east-1
              ResourceRole: Target
              Tags:
                aws:cloudformation:logical-id: DataBucket
                aws:cloudformation:stack-id: arn:aws:cloudformation:us-east-1:123456789012:stack/Panther/a1b2c345-12f6-11ef-8c74-12deb08d9ef1
                aws:cloudformation:stack-name: Panther
              Type: AwsS3Bucket
            - Id: arn:aws:s3:::panther-databucket/object
              Partition: aws
              Region: us-east-1
              ResourceRole: Target
              Type: AwsS3Object
            - Details:
                AwsIamAccessKey:
                    AccessKeyId: ABCDEFG1HIJ2KLMNOPQR
                    AccountId: "123456789012"
                    PrincipalId: ABCDEFG1HIJ2KLMNOPQR:john.doe
                    PrincipalType: AssumedRole
                    SessionContext:
                        Attributes:
                            CreationDate: "2024-05-23T20:20:57Z"
                            MfaAuthenticated: false
                        SessionIssuer:
                            AccountId: "123456789012"
                            Arn: arn:aws:iam::123456789012:role/tester
                            PrincipalId: ABCDEFG1HIJ2KLMNOPQR
                            Type: Role
                            UserName: tester
              Id: ABCDEFG1HIJ2KLMNOPQR
              Partition: aws
              Region: us-east-1
              ResourceRole: Actor
              Type: AwsIamAccessKey
            - Id: ABCDEFG1HIJ2KLMNOPQR
              Partition: aws
              Region: us-east-1
              ResourceRole: Actor
              Type: AwsIamRole
        SchemaVersion: "2018-10-08"
        Severity:
            Label: HIGH
            Normalized: 70
        Title: Suspicious activity detected accessing private decoy S3 bucket panther-databucket
        Types:
            - Unusual Behaviors
        UpdatedAt: "2024-05-24 00:26:57.000000000"
        Workflow:
            Status: NEW
        WorkflowState: NEW
        p_any_actor_ids: []
        p_any_aws_account_ids: []
        p_any_aws_arns: []
        p_any_ip_addresses: []
        p_any_trace_ids: []
        p_any_usernames: []
        p_event_time: "2024-05-24 00:26:57.000000000"
        p_log_type: AWS.SecurityFindingFormat
        p_parse_time: "2024-05-24 00:30:04.569556803"
        p_row_id: 624c79c882affe88a1dce9c31fb68f0e
        p_schema_version: 0
        p_source_id: e29fd64f-53d9-43ab-92ca-575a8af289e6
        p_source_label: AWS Security Hub
    - Name: S3-Decoy-Not-Accessed
      ExpectedResult: false
      Log:
        Action:
            ActionType: AWS_API_CALL
            AwsApiCallAction:
                Api: ListBuckets
                CallerType: remoteIp
                DomainDetails: {}
                RemoteIpDetails:
                    City: {}
                    Country: {}
                    GeoLocation: {}
                    IpAddressV4: 111.111.111.111
                    Organization: {}
                ServiceName: s3.amazonaws.com
            DnsRequestAction: {}
            NetworkConnectionAction:
                LocalPortDetails: {}
                RemotePortDetails: {}
            PortProbeAction: {}
        AwsAccountId: "123456789012"
        CompanyName: Custom
        CreatedAt: "2024-05-24 00:26:57.000000000"
        Description: Private decoy S3 bucket panther-databucket was not accessed by arn:aws:iam::123456789012:user/tester. This S3 bucket has been provisioned to monitor and generate security events when accessed and can be an indicator of unintended or unauthorized access to your AWS Account.
        FindingProviderFields:
            Severity:
                Label: HIGH
                Normalized: 70
            Types:
                - Unusual Behaviors
        GeneratorId: s3.amazonaws.com
        Id: ABC9ONWNS3155VIEJC8U
        ProcessedAt: "2024-05-24T00:27:12.237Z"
        ProductArn: arn:aws:securityhub:us-east-1:123456789012:product/123456789012/default
        ProductFields:
            Custom/DecoyDetector/apiResult: SUCCESS
            Custom/DecoyDetector/requestID: ab1cd234-1986-4c45-8546-fdb1776e23b0
            Custom/DecoyDetector/userAgent: '[Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36]'
            aws/securityhub/CompanyName: Personal
            aws/securityhub/FindingId: arn:aws:service:region:123456789012:resource/12345ab6-436d-4d59-ac58-ed6b3127e440
            aws/securityhub/ProductName: Default
        ProductName: DecoyDetector
        RecordState: ACTIVE
        Region: us-east-1
        Resources:
            - Id: arn:aws:s3:::panther-databucket
              Partition: aws
              Region: us-east-1
              ResourceRole: Target
              Tags:
                aws:cloudformation:logical-id: DataBucket
                aws:cloudformation:stack-id: arn:aws:cloudformation:us-east-1:123456789012:stack/Panther/a1b2c345-12f6-11ef-8c74-12deb08d9ef1
                aws:cloudformation:stack-name: Panther
              Type: AwsS3Bucket
            - Id: arn:aws:s3:::panther-databucket/object
              Partition: aws
              Region: us-east-1
              ResourceRole: Target
              Type: AwsS3Object
            - Details:
                AwsIamAccessKey:
                    AccessKeyId: ABCDEFG1HIJ2KLMNOPQR
                    AccountId: "123456789012"
                    PrincipalId: ABCDEFG1HIJ2KLMNOPQR:john.doe
                    PrincipalType: AssumedRole
                    SessionContext:
                        Attributes:
                            CreationDate: "2024-05-23T20:20:57Z"
                            MfaAuthenticated: false
                        SessionIssuer:
                            AccountId: "123456789012"
                            Arn: arn:aws:iam::123456789012:role/tester
                            PrincipalId: ABCDEFG1HIJ2KLMNOPQR
                            Type: Role
                            UserName: tester
              Id: ABCDEFG1HIJ2KLMNOPQR
              Partition: aws
              Region: us-east-1
              ResourceRole: Actor
              Type: AwsIamAccessKey
            - Id: ABCDEFG1HIJ2KLMNOPQR
              Partition: aws
              Region: us-east-1
              ResourceRole: Actor
              Type: AwsIamRole
        SchemaVersion: "2018-10-08"
        Severity:
            Label: HIGH
            Normalized: 70
        Title: Non-Suspicious activity detected accessing private decoy S3 bucket panther-databucket
        Types:
            - Unusual Behaviors
        UpdatedAt: "2024-05-24 00:26:57.000000000"
        Workflow:
            Status: NEW
        WorkflowState: NEW
        p_any_actor_ids: []
        p_any_aws_account_ids: []
        p_any_aws_arns: []
        p_any_ip_addresses: []
        p_any_trace_ids: []
        p_any_usernames: []
        p_event_time: "2024-05-24 00:26:57.000000000"
        p_log_type: AWS.SecurityFindingFormat
        p_parse_time: "2024-05-24 00:30:04.569556803"
        p_row_id: 624c79c882affe88a1dce9c31fb68f0e
        p_schema_version: 0
        p_source_id: e29fd64f-53d9-43ab-92ca-575a8af289e6
        p_source_label: AWS Security Hub

Detection logic

Condition

GeneratorId eq "s3.amazonaws.com"
Action.AwsApiCallAction.Api in ["HeadObject", "GetObject", "GetObjectAcl", "GetObjectAttributes", "GetObjectLegalHold", "GetObjectLockConfiguration", "GetObjectRetention", "GetObjectTagging", "GetObjectTorrent", "PutObject", "PutObjectAcl", "PutObjectLegalHold", "PutObjectLockConfiguration", "PutObjectRetention", "PutObjectTagging", "SelectObjectContent", "DeleteObject", "DeleteObjects", "DeleteObjectTagging"]

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
`Action.AwsApiCallAction.Api`	in	`DeleteObject` `DeleteObjectTagging` `DeleteObjects` `GetObject` `GetObjectAcl` `GetObjectAttributes` `GetObjectLegalHold` `GetObjectLockConfiguration` `GetObjectRetention` `GetObjectTagging` `GetObjectTorrent` `HeadObject` `PutObject` `PutObjectAcl` `PutObjectLegalHold` `PutObjectLockConfiguration` `PutObjectRetention` `PutObjectTagging` `SelectObjectContent`
`GeneratorId`	eq	`s3.amazonaws.com`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-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`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Decoy S3 Accessed

Rule body yaml

Detection logic

Condition

Indicators

Keyboard shortcuts

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