StopInstance FOLLOWED BY ModifyInstanceAttributes

Severity: high
Time window: 90m
Match by: p_alert_context.instance_ids
Reference: https://unit42.paloaltonetworks.com/malicious-operations-of-exposed-iam-keys-cryptojacking/
Source: github.com/panther-labs/panther-analysis

Identifies when StopInstance and ModifyInstanceAttributes CloudTrail events occur in a short period of time. Since EC2 startup scripts cannot be modified without first stopping the instance, StopInstances should be a signal.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059` Command and Scripting Interpreter

Rule body yaml

AnalysisType: correlation_rule
RuleID: "AWS.EC2.StopInstance.FOLLOWED.BY.ModifyInstanceAttributes"
DisplayName: "StopInstance FOLLOWED BY ModifyInstanceAttributes"
Enabled: true
Severity: High
Description: Identifies when StopInstance and ModifyInstanceAttributes CloudTrail events occur in a short period of time. Since EC2 startup scripts cannot be modified without first stopping the instance, StopInstances should be a signal.
Reference: https://unit42.paloaltonetworks.com/malicious-operations-of-exposed-iam-keys-cryptojacking/
Reports:
  MITRE ATT&CK:
    - TA0002:T1059
Detection:
    - Sequence:
        - ID: StopInstance
          RuleID: AWS.EC2.StopInstances
        - ID: StartupScriptChange
          RuleID: AWS.EC2.Startup.Script.Change
      Transitions:
        - ID: StopInstance FOLLOWED BY StartupScriptChange
          From: StopInstance
          To: StartupScriptChange
          WithinTimeFrameMinutes: 90
          Match:
            - On: p_alert_context.instance_ids
      LookbackWindowMinutes: 2160
      Schedule:
        RateMinutes: 1440
        TimeoutMinutes: 5
Tests:
    - Name: Instance Stopped, Followed By Script Change
      ExpectedResult: true
      RuleOutputs:
        - ID: StopInstance
          Matches:
            p_alert_context.instance_ids:
              'i-abcdef0123456789a':
                - "2024-06-01T10:00:01Z"
        - ID: StartupScriptChange
          Matches:
            p_alert_context.instance_ids:
              'i-abcdef0123456789a':
                - "2024-06-01T10:01:01Z"
    - Name: Instance Stopped, Not Followed By Script Change
      ExpectedResult: false
      RuleOutputs:
        - ID: StopInstance
          Matches:
            p_alert_context.instance_ids:
              'i-abcdef0123456789a':
                - "2024-06-01T10:00:01Z"

Detection logic

Stage 1: `step StopInstance` ordered before `$StartupScriptChange`

References detection AWS.EC2.StopInstances.

Stage 2: `step StartupScriptChange` ordered after `$StopInstance`

References detection AWS.EC2.Startup.Script.Change.

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`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)

StopInstance FOLLOWED BY ModifyInstanceAttributes

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Stage 1: `step StopInstance` ordered before `$StartupScriptChange`

Stage 2: `step StartupScriptChange` ordered after `$StopInstance`

Keyboard shortcuts

Search operators

StopInstance FOLLOWED BY ModifyInstanceAttributes

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Stage 1: step StopInstance ordered before $StartupScriptChange

Stage 2: step StartupScriptChange ordered after $StopInstance

Stage 1: `step StopInstance` ordered before `$StartupScriptChange`

Stage 2: `step StartupScriptChange` ordered after `$StopInstance`