RDS Database Security Group Modification

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

Detects changes to the security group entries for RDS databases. This can indicate that a misconfiguration has occurred which potentially exposes the database to the public internet, a wider audience within the VPC or that removal of valid rules has occurred which could impact the availability of the database to legitimate services and users.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application

Event coverage

Provider	Event
AWS-rds	AuthorizeDBSecurityGroupIngress
AWS-rds	CreateDBSecurityGroup
AWS-rds	DeleteDBSecurityGroup
AWS-rds	RevokeDBSecurityGroupIngress

Rules detecting the same action

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

AWS RDS Security Group Ingress Authorized (Panther)

Rule body yaml

title: RDS Database Security Group Modification
id: 14f3f1c8-02d5-43a2-a191-91ffb52d3015
status: test
description: |
    Detects changes to the security group entries for RDS databases.
    This can indicate that a misconfiguration has occurred which potentially exposes the database to the public internet, a wider audience within the VPC or that removal of valid rules has occurred which could impact the availability of the database to legitimate services and users.
references:
    - https://www.gorillastack.com/blog/real-time-events/important-aws-cloudtrail-security-events-tracking/
author: jamesc-grafana
date: 2024-07-11
tags:
    - attack.initial-access
    - attack.t1190
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: 'rds.amazonaws.com'
        eventName:
            - 'AuthorizeDBSecurityGroupIngress'
            - 'CreateDBSecurityGroup'
            - 'DeleteDBSecurityGroup'
            - 'RevokeDBSecurityGroupIngress'
    condition: selection
falsepositives:
    - Creation of a new Database that needs new security group rules
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    eventSource: 'rds.amazonaws.com'
    eventName:
        - 'AuthorizeDBSecurityGroupIngress'
        - 'CreateDBSecurityGroup'
        - 'DeleteDBSecurityGroup'
        - 'RevokeDBSecurityGroupIngress'

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	`AuthorizeDBSecurityGroupIngress` `CreateDBSecurityGroup` `DeleteDBSecurityGroup` `RevokeDBSecurityGroupIngress`
`eventSource`	eq	`rds.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)

RDS Database Security Group Modification

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Indicators

Keyboard shortcuts

Search operators

RDS Database Security Group Modification

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`