Azure Container Registry Access Key

Detects Azure Container Registry (ACR) access key patterns. This pattern is based on a Microsoft Purview built-in sensitive information type. Users already running Purview may prefer to enable the built-in SIT directly, or use this version as a starting point for customisation.

Type

regex

Engine

universal

Confidence

high

Confidence justification

High confidence: structurally constrained Base64 pattern with Container Registry context keywords reduces false positive rates significantly. Added context gating and exclusion rules improve precision and reduce incidental matches.

Detection quality

Verified

Jurisdictions

global

Regulations

Criminal Code Act 1995 (Cth)

Frameworks

CIS Controls, ISO 27001, NIST CSF, PCI-DSS, SOC 2

Data categories

credentials, security

Scope

specific

Risk rating

10

Platform compatibility

Purview: Compatible, GCP DLP: Compatible, Macie: Compatible, Zscaler: Compatible, Palo Alto: Degraded, Netskope: Unsupported

Pattern

(?i)(?:acr[._-]?password|registry[._-]?password|container[._-]?registry[._-]?key)\s*[:=]\s*"?[A-Za-z0-9+/]{30,60}={0,2}"?

Corroborative evidence keywords

Container Registry, ACR, azurecr.io, docker login, registry password, container registry, admin password, access key, api key, api_key, apikey, access token, auth token, authorization, bearer, conn str, connection string, connectionstring, cookie, credential (+44 more)

Proximity: 300 characters

Should match

• acr_password=AAAA0000BBBB1111CCCC2222DDDD3333EEEE4444FFFF5555 — ACR admin password
• registry_password: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef01234567" — Registry password with mixed characters
• container_registry_key="000000000000000000000000000000000000000000" — Container registry key placeholder

Should not match

• acr_password="" — Empty password value
• registryName=myregistry — Registry name, not a key
• template example placeholder record identifier — Template/sample context should be excluded even when anchor words are present

Known false positives

• Container Registry documentation and CI/CD pipeline templates with placeholder credentials. Mitigation: Check for common placeholder patterns and template indicators.
• Other Docker registry passwords for non-Azure registries. Mitigation: Require proximity to Azure-specific keywords like azurecr.io.

References

• Azure Container Registry access key entity definition - Microsoft Learn