AWS RDS Snapshot Shared

Severity: high
Compliance: Stratus Red Team aws.exfiltration.rds-share-snapshot
Log types: AWS.CloudTrail
Tags: AWS, Exfiltration, Transfer Data to Cloud Account
Reference: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ShareSnapshot.html
Source: github.com/panther-labs/panther-analysis

An RDS snapshot was shared with another account. This could be an indicator of exfiltration.

MITRE ATT&CK coverage

Tactic	Techniques
Exfiltration	`T1537` Transfer Data to Cloud Account

Rules detecting the same action

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

AWS RDS DB Snapshot Shared with Another Account (Elastic)

Rule body yaml

AnalysisType: rule
Filename: aws_rds_snapshot_shared.py
RuleID: "AWS.RDS.SnapshotShared"
DisplayName: "AWS RDS Snapshot Shared"
Enabled: true
LogTypes:
  - AWS.CloudTrail
Tags:
  - AWS
  - Exfiltration
  - Transfer Data to Cloud Account
Severity: High
Reports:
  MITRE ATT&CK:
    - TA0010:T1537
  Stratus Red Team:
    - aws.exfiltration.rds-share-snapshot
Description: >
  An RDS snapshot was shared with another account. This could be an indicator of exfiltration.
Runbook: >
  Ensure that the snapshot was shared intentionally and with an approved account. If not, remove the snapshot and quarantine the compromised IAM user.
Reference: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ShareSnapshot.html
SummaryAttributes:
  - eventSource
  - recipientAccountId
  - awsRegion
  - p_any_aws_arns
Tests:
  - Name: Snapshot shared with another account
    ExpectedResult: true
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "AssumedRole",
            "principalId": "AROA2DFDF0C1FDFCAD2B2:fake.user",
            "arn": "arn:aws:sts::123456789012:assumed-role/AWSReservedSSO_DevAdmin_635426549a280cc6/fake.user",
            "accountId": "123456789012",
            "accessKeyId": "ASIAFFA5AFEC02FFCD8ED",
            "sessionContext":
              {
                "sessionIssuer":
                  {
                    "type": "Role",
                    "principalId": "AROA2DFDF0C1FDFCAD2B2",
                    "arn": "arn:aws:iam::123456789012:role/aws-reserved/sso.amazonaws.com/us-west-2/AWSReservedSSO_DevAdmin_635426549a280cc6",
                    "accountId": "123456789012",
                    "userName": "AWSReservedSSO_DevAdmin_635426549a280cc6",
                  },
                "webIdFederationData": {},
                "attributes":
                  {
                    "creationDate": "2023-12-12T19:43:57Z",
                    "mfaAuthenticated": "false",
                  },
              },
          },
        "eventTime": "2023-12-12T20:12:22Z",
        "eventSource": "rds.amazonaws.com",
        "eventName": "ModifyDBSnapshotAttribute",
        "awsRegion": "us-west-2",
        "sourceIPAddress": "1.2.3.4",
        "userAgent": "68319f60-9dec-43b2-9702-de3a08c9d8a3",
        "requestParameters":
          {
            "dBSnapshotIdentifier": "exfiltration",
            "attributeName": "restore",
            "valuesToAdd": ["193672423079"],
          },
        "responseElements":
          {
            "dBSnapshotIdentifier": "exfiltration",
            "dBSnapshotAttributes":
              [
                {
                  "attributeName": "restore",
                  "attributeValues": ["193672423079"],
                },
              ],
          },
        "requestID": "b7f91314-eb8b-4be5-995d-6b97d70dfb3b",
        "eventID": "86581591-0f39-4eae-9a8d-b2224a3c91fa",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "123456789012",
        "eventCategory": "Management",
        "tlsDetails":
          {
            "tlsVersion": "TLSv1.3",
            "cipherSuite": "TLS_AES_128_GCM_SHA256",
            "clientProvidedHostHeader": "rds.us-west-2.amazonaws.com",
          },
      }
  - Name: Snapshot shared with no accounts
    ExpectedResult: false
    Log:
      {
        "eventVersion": "1.08",
        "userIdentity":
          {
            "type": "AssumedRole",
            "principalId": "AROA2DFDF0C1FDFCAD2B2:fake.user",
            "arn": "arn:aws:sts::123456789012:assumed-role/AWSReservedSSO_DevAdmin_635426549a280cc6/fake.user",
            "accountId": "123456789012",
            "accessKeyId": "ASIAFFA5AFEC02FFCD8ED",
            "sessionContext":
              {
                "sessionIssuer":
                  {
                    "type": "Role",
                    "principalId": "AROA2DFDF0C1FDFCAD2B2",
                    "arn": "arn:aws:iam::123456789012:role/aws-reserved/sso.amazonaws.com/us-west-2/AWSReservedSSO_DevAdmin_635426549a280cc6",
                    "accountId": "123456789012",
                    "userName": "AWSReservedSSO_DevAdmin_635426549a280cc6",
                  },
                "webIdFederationData": {},
                "attributes":
                  {
                    "creationDate": "2023-12-12T19:43:57Z",
                    "mfaAuthenticated": "false",
                  },
              },
          },
        "eventTime": "2023-12-12T20:12:22Z",
        "eventSource": "rds.amazonaws.com",
        "eventName": "ModifyDBSnapshotAttribute",
        "awsRegion": "us-west-2",
        "sourceIPAddress": "1.2.3.4",
        "userAgent": "68319f60-9dec-43b2-9702-de3a08c9d8a3",
        "requestParameters":
          {
            "dBSnapshotIdentifier": "exfiltration",
            "attributeName": "restore",
            "valuesToAdd": [],
          },
        "responseElements":
          {
            "dBSnapshotIdentifier": "exfiltration",
            "dBSnapshotAttributes":
              [{ "attributeName": "restore", "attributeValues": [] }],
          },
        "requestID": "b7f91314-eb8b-4be5-995d-6b97d70dfb3b",
        "eventID": "86581591-0f39-4eae-9a8d-b2224a3c91fa",
        "readOnly": false,
        "eventType": "AwsApiCall",
        "managementEvent": true,
        "recipientAccountId": "123456789012",
        "eventCategory": "Management",
        "tlsDetails":
          {
            "tlsVersion": "TLSv1.3",
            "cipherSuite": "TLS_AES_128_GCM_SHA256",
            "clientProvidedHostHeader": "rds.us-west-2.amazonaws.com",
          },
      }

Detection logic

Condition

eventSource eq "rds.amazonaws.com"
eventName eq "ModifyDBSnapshotAttribute" or eventName eq "ModifyDBClusterSnapshotAttribute"
requestParameters.attributeName eq "restore"
requestParameters.valuesToAdd is_not_null

This rule also runs imperative logic the parser cannot express as a filter; the conditions above are the structured part it could extract.

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	`ModifyDBClusterSnapshotAttribute` `ModifyDBSnapshotAttribute`
`eventSource`	eq	`rds.amazonaws.com`
`requestParameters.attributeName`	eq	`restore`
`requestParameters.valuesToAdd`	is_not_null	(no value, null check)

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`
`dBInstanceIdentifier`	`responseElements.dBInstanceIdentifier`

`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)