AWS CloudWatch Logs Data Retention

Severity: low
Tags: AWS, Panther
Reference: https://docs.aws.amazon.com/cli/latest/reference/logs/put-retention-policy.html
Source: github.com/panther-labs/panther-analysis

By default, logs are kept indefinitely and never expire. You can adjust the retention policy for each log group, keeping the indefinite retention, or choosing a specific retention period.

Rule body yaml

AnalysisType: policy
Filename: aws_cloudwatch_loggroup_data_retention.py
PolicyID: "AWS.CloudWatchLogs.DataRetention1Year"
DisplayName: "AWS CloudWatch Logs Data Retention"
Enabled: true
ResourceTypes:
  - AWS.CloudWatch.LogGroup
Tags:
  - AWS
  - Panther
Severity: Low
Description: >
  By default, logs are kept indefinitely and never expire. You can adjust the retention policy
  for each log group, keeping the indefinite retention, or choosing a specific retention period.
Runbook: |
  Change the CloudWatch log group retention from the CloudWatch Logs web console,
  SDK, CloudFormation, or any other supported method.
Reference: https://docs.aws.amazon.com/cli/latest/reference/logs/put-retention-policy.html
Tests:
  - Name: Unlimited Log Retention
    ExpectedResult: true
    Resource:
      {
        "ARN": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "AccountId": "123456789012",
        "Arn": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "CreationTime": 1234567890123,
        "KmsKeyId": "arn:aws:kms:us-west-2:123456789012:key/12345678-1234-1234-1234-123456789012",
        "LogGroupName": "LogGroup-2",
        "MetricFilterCount": 0,
        "Name": "LogGroup-2",
        "Region": "us-west-2",
        "ResourceID": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "ResourceType": "AWS.CloudWatch.LogGroup",
        "RetentionInDays": null,
        "StoredBytes": 0,
        "Tags": { "Key1Name": "Value1" },
        "TimeCreated": "2009-02-13T15:31:30.000-08:00",
      }
  - Name: Logs Retained 1 Year
    ExpectedResult: true
    Resource:
      {
        "ARN": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "AccountId": "123456789012",
        "Arn": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "CreationTime": 1234567890123,
        "KmsKeyId": null,
        "LogGroupName": "LogGroup-2",
        "MetricFilterCount": 0,
        "Name": "LogGroup-2",
        "Region": "us-west-2",
        "ResourceID": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "ResourceType": "AWS.CloudWatch.LogGroup",
        "RetentionInDays": 365,
        "StoredBytes": 0,
        "Tags": { "Key1Name": "Value1" },
        "TimeCreated": "2009-02-13T15:31:30.000-08:00",
      }
  - Name: Logs Retained 2 Years
    ExpectedResult: true
    Resource:
      {
        "ARN": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "AccountId": "123456789012",
        "Arn": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "CreationTime": 1234567890123,
        "KmsKeyId": null,
        "LogGroupName": "LogGroup-2",
        "MetricFilterCount": 0,
        "Name": "LogGroup-2",
        "Region": "us-west-2",
        "ResourceID": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "ResourceType": "AWS.CloudWatch.LogGroup",
        "RetentionInDays": 730,
        "StoredBytes": 0,
        "Tags": { "Key1Name": "Value1" },
        "TimeCreated": "2009-02-13T15:31:30.000-08:00",
      }
  - Name: Logs Retained 1 Week
    ExpectedResult: false
    Resource:
      {
        "ARN": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "AccountId": "123456789012",
        "Arn": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "CreationTime": 1234567890123,
        "KmsKeyId": null,
        "LogGroupName": "LogGroup-2",
        "MetricFilterCount": 0,
        "Name": "LogGroup-2",
        "Region": "us-west-2",
        "ResourceID": "arn:aws:logs:us-west-2:1234456789012:log-group:LogGroup-2",
        "ResourceType": "AWS.CloudWatch.LogGroup",
        "RetentionInDays": 7,
        "StoredBytes": 0,
        "Tags": { "Key1Name": "Value1" },
        "TimeCreated": "2009-02-13T15:31:30.000-08:00",
      }

Detection logic

Condition

not (RetentionInDays is_null or RetentionInDays ge "365")

Exclusions

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

Field	Kind	Excluded values
`RetentionInDays`	ge	`365`
`RetentionInDays`	is_null	(no value, null check)

`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)

AWS CloudWatch Logs Data Retention

Rule body yaml

Detection logic

Condition

Exclusions

Keyboard shortcuts

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