AWS EC2 Disable EBS Encryption

Status: stable
Severity: medium
Log source: product aws, service cloudtrail
Author: Sittikorn S
Source: github.com/SigmaHQ/sigma

Identifies disabling of default Amazon Elastic Block Store (EBS) encryption in the current region. Disabling default encryption does not change the encryption status of your existing volumes.

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1486` Data Encrypted for Impact, `T1565` Data Manipulation

Event coverage

Provider	Event
AWS-ec2	DisableEbsEncryptionByDefault

Rules detecting the same action

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

AWS EC2 EBS Encryption Disabled (Panther)
AWS EC2 Encryption Disabled (Elastic)

Rule body yaml

title: AWS EC2 Disable EBS Encryption
id: 16124c2d-e40b-4fcc-8f2c-5ab7870a2223
status: stable
description: |
  Identifies disabling of default Amazon Elastic Block Store (EBS) encryption in the current region.
  Disabling default encryption does not change the encryption status of your existing volumes.
references:
    - https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DisableEbsEncryptionByDefault.html
author: Sittikorn S
date: 2021-06-29
modified: 2021-08-20
tags:
    - attack.impact
    - attack.t1486
    - attack.t1565
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: ec2.amazonaws.com
        eventName: DisableEbsEncryptionByDefault
    condition: selection
falsepositives:
    - System Administrator Activities
    - DEV, UAT, SAT environment. You should apply this rule with PROD account only.
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    eventSource: ec2.amazonaws.com
    eventName: DisableEbsEncryptionByDefault

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	`DisableEbsEncryptionByDefault`
`eventSource`	eq	`ec2.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)

AWS EC2 Disable EBS Encryption

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

AWS EC2 Disable EBS Encryption

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`