AWS RDS Master Password Change

Status: test
Severity: medium
Log source: product aws, service cloudtrail
Author: faloker
Source: github.com/SigmaHQ/sigma

Detects the change of database master password. It may be a part of data exfiltration.

MITRE ATT&CK coverage

Tactic	Techniques
Exfiltration	`T1020` Automated Exfiltration

Event coverage

Provider	Event
AWS-rds	ModifyDBInstance

Rules detecting the same action

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

AWS RDS DB Instance Made Public (Elastic)
AWS RDS DB Instance or Cluster Deletion Protection Disabled (Elastic)
AWS RDS DB Instance or Cluster Password Modified (Elastic)
AWS RDS Deletion Protection Disabled (Panther)
AWS RDS Instance Modified to be Publicly Accessible (Panther)
AWS RDS Master Password Updated (Panther)
AWS RDS Snapshot Deleted (Elastic)

Rule body yaml

title: AWS RDS Master Password Change
id: 8a63cdd4-6207-414a-85bc-7e032bd3c1a2
status: test
description: Detects the change of database master password. It may be a part of data exfiltration.
references:
    - https://github.com/RhinoSecurityLabs/pacu/blob/866376cd711666c775bbfcde0524c817f2c5b181/pacu/modules/rds__explore_snapshots/main.py
author: faloker
date: 2020-02-12
modified: 2022-10-05
tags:
    - attack.exfiltration
    - attack.t1020
logsource:
    product: aws
    service: cloudtrail
detection:
    selection_source:
        eventSource: rds.amazonaws.com
        responseElements.pendingModifiedValues.masterUserPassword|contains: '*'
        eventName: ModifyDBInstance
    condition: selection_source
falsepositives:
    - Benign changes to a db instance
level: medium

Stages and Predicates

Stage 0: `condition`

selection_source

Stage 1: `selection_source`

selection_source:
    eventSource: rds.amazonaws.com
    responseElements.pendingModifiedValues.masterUserPassword|contains: '*'
    eventName: ModifyDBInstance

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	`ModifyDBInstance`
`eventSource`	eq	`rds.amazonaws.com`
`responseElements.pendingModifiedValues.masterUserPassword`	match	`*`

`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 RDS Master Password Change

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_source`

Indicators

Keyboard shortcuts

Search operators

AWS RDS Master Password Change

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_source

Indicators

Stage 0: `condition`

Stage 1: `selection_source`