AWS ACM Secure Algorithms

Severity: high
Compliance: PCI 2.2.3
Tags: AWS, Configuration Required, PCI, Defense Evasion:Impair Defenses
Reference: https://docs.aws.amazon.com/acm/latest/userguide/acm-certificate.html#algorithms
Source: github.com/panther-labs/panther-analysis

This policy validates that all ACM certificates are using secure key and signature algorithms.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1562` Impair Defenses

Rule body yaml

AnalysisType: policy
Filename: aws_acm_certificate_has_secure_algorithms.py
PolicyID: "AWS.ACM.HasSecureAlgorithms"
DisplayName: "AWS ACM Secure Algorithms"
Enabled: false
ResourceTypes:
  - AWS.ACM.Certificate
Tags:
  - AWS
  - Configuration Required
  - PCI
  - Defense Evasion:Impair Defenses
Reports:
  PCI:
    - 2.2.3
  MITRE ATT&CK:
    - TA0005:T1562
Severity: High
Description: >
  This policy validates that all ACM certificates are using secure key and signature algorithms.
Runbook: >
  Delete the insecure certificate, and re-create with appropriately secure key and signature algorithms.
Reference: https://docs.aws.amazon.com/acm/latest/userguide/acm-certificate.html#algorithms
Tests:
  - Name: Certificate Has Secure Algorithms
    ExpectedResult: true
    Resource:
      {
        "AccountId": "123456789012",
        "Arn": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "CertificateAuthorityArn": null,
        "DomainName": "example.com",
        "DomainValidationOptions":
          [
            {
              "DomainName": "example.com",
              "ResourceRecord":
                {
                  "Name": "aaaa.example.com.",
                  "Type": "CNAME",
                  "Value": "aaaa.bbbb.acm-validations.aws.",
                },
              "ValidationDomain": "example.com",
              "ValidationEmails": null,
              "ValidationMethod": "DNS",
              "ValidationStatus": "SUCCESS",
            },
          ],
        "ExtendedKeyUsages":
          [
            {
              "Name": "TLS_WEB_SERVER_AUTHENTICATION",
              "OID": "1.3.6.1.5.5.7.3.1",
            },
          ],
        "FailureReason": null,
        "InUseBy": null,
        "IssuedAt": "2019-01-01T00:00:00Z",
        "Issuer": "Amazon",
        "KeyAlgorithm": "RSA-2048",
        "KeyUsages": [{ "Name": "DIGITAL_SIGNATURE" }],
        "Name": "example.com",
        "NotAfter": "2020-01-01T00:00:00Z",
        "NotBefore": "2019-01-01T00:00:00Z",
        "Options": { "CertificateTransparencyLoggingPreference": "ENABLED" },
        "Region": "us-east-1",
        "RenewalEligibility": "INELIGIBLE",
        "RenewalSummary": null,
        "ResourceId": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "ResourceType": "AWS.ACM.Certificate",
        "RevocationReason": null,
        "RevokedAt": null,
        "Serial": "00:00:00",
        "SignatureAlgorithm": "SHA256WITHRSA",
        "Status": "ISSUED",
        "Subject": "CN=example.com",
        "SubjectAlternativeNames": ["example.com"],
        "Tags": null,
        "TimeCreated": null,
        "Type": "AMAZON_ISSUED",
      }
  - Name: Certificate Has One Insecure Algorithm
    ExpectedResult: false
    Resource:
      {
        "AccountId": "123456789012",
        "Arn": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "CertificateAuthorityArn": null,
        "DomainName": "example.com",
        "DomainValidationOptions":
          [
            {
              "DomainName": "example.com",
              "ResourceRecord":
                {
                  "Name": "aaaa.example.com.",
                  "Type": "CNAME",
                  "Value": "aaaa.bbbb.acm-validations.aws.",
                },
              "ValidationDomain": "example.com",
              "ValidationEmails": null,
              "ValidationMethod": "DNS",
              "ValidationStatus": "SUCCESS",
            },
          ],
        "ExtendedKeyUsages":
          [
            {
              "Name": "TLS_WEB_SERVER_AUTHENTICATION",
              "OID": "1.3.6.1.5.5.7.3.1",
            },
          ],
        "FailureReason": null,
        "InUseBy": null,
        "IssuedAt": "2019-01-01T00:00:00Z",
        "Issuer": "Amazon",
        "KeyAlgorithm": "LANMAN",
        "KeyUsages": [{ "Name": "DIGITAL_SIGNATURE" }],
        "Name": "example.com",
        "NotAfter": "2020-01-01T00:00:00Z",
        "NotBefore": "2019-01-01T00:00:00Z",
        "Options": { "CertificateTransparencyLoggingPreference": "ENABLED" },
        "Region": "us-east-1",
        "RenewalEligibility": "INELIGIBLE",
        "RenewalSummary": null,
        "ResourceId": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "ResourceType": "AWS.ACM.Certificate",
        "RevocationReason": null,
        "RevokedAt": null,
        "Serial": "00:00:00",
        "SignatureAlgorithm": "SHA256WITHRSA",
        "Status": "ISSUED",
        "Subject": "CN=example.com",
        "SubjectAlternativeNames": ["example.com"],
        "Tags": null,
        "TimeCreated": null,
        "Type": "AMAZON_ISSUED",
      }
  - Name: Certificate Has Two Insecure Agorithms
    ExpectedResult: false
    Resource:
      {
        "AccountId": "123456789012",
        "Arn": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "CertificateAuthorityArn": null,
        "DomainName": "example.com",
        "DomainValidationOptions":
          [
            {
              "DomainName": "example.com",
              "ResourceRecord":
                {
                  "Name": "aaaa.example.com.",
                  "Type": "CNAME",
                  "Value": "aaaa.bbbb.acm-validations.aws.",
                },
              "ValidationDomain": "example.com",
              "ValidationEmails": null,
              "ValidationMethod": "DNS",
              "ValidationStatus": "SUCCESS",
            },
          ],
        "ExtendedKeyUsages":
          [
            {
              "Name": "TLS_WEB_SERVER_AUTHENTICATION",
              "OID": "1.3.6.1.5.5.7.3.1",
            },
          ],
        "FailureReason": null,
        "InUseBy": null,
        "IssuedAt": "2019-01-01T00:00:00Z",
        "Issuer": "Amazon",
        "KeyAlgorithm": "LANMAN",
        "KeyUsages": [{ "Name": "DIGITAL_SIGNATURE" }],
        "Name": "example.com",
        "NotAfter": "2020-01-01T00:00:00Z",
        "NotBefore": "2019-01-01T00:00:00Z",
        "Options": { "CertificateTransparencyLoggingPreference": "ENABLED" },
        "Region": "us-east-1",
        "RenewalEligibility": "INELIGIBLE",
        "RenewalSummary": null,
        "ResourceId": "arn:aws:acm:us-east-1:123456789012:certificate/1",
        "ResourceType": "AWS.ACM.Certificate",
        "RevocationReason": null,
        "RevokedAt": null,
        "Serial": "00:00:00",
        "SignatureAlgorithm": "MD5",
        "Status": "ISSUED",
        "Subject": "CN=example.com",
        "SubjectAlternativeNames": ["example.com"],
        "Tags": null,
        "TimeCreated": null,
        "Type": "AMAZON_ISSUED",
      }

Detection logic

Condition

not (KeyAlgorithm in "RSA-2048" and SignatureAlgorithm in "SHA256WITHRSA")

Exclusions

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

Field	Kind	Excluded values
`KeyAlgorithm`	eq	`RSA-2048`
`SignatureAlgorithm`	eq	`SHA256WITHRSA`

`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 ACM Secure Algorithms

MITRE ATT&CK coverage

Rule body yaml

Detection logic

Condition

Exclusions

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