How to Securely Store SIM Credentials in Scripts > 자유게시판

Many automation and IoT deployments rely on embedding SIM credentials in code, yet this practice exposes systems to significant vulnerabilities when mismanaged

SIM credentials typically include the IMSI number, authentication keys like Ki, and sometimes PIN codes

These are highly sensitive because they can be used to impersonate a device on a cellular network, leading to fraud, data interception, or service abuse

Your primary security guideline must be: never write SIM keys or IMSI values as static strings in your scripts

Do not hardcode them as literals, store them in.env files, or place them in JSON, YAML, or INI config files next to your executable

Never assume internal use equals safety—credentials exposed in logs or repositories can be harvested by insiders or automated scrapers

Replace hardcoded secrets with a centralized, encrypted secrets vault

Many cloud providers offer secrets management services such as AWS Secrets Manager, Azure Key Vault, or Google Cloud Secret Manager

These services encrypt credentials at rest and in transit, provide fine-grained access controls, and log all access attempts

Use ephemeral authentication mechanisms like AWS STS, Azure Managed Identity, or GCP Workload Identity to dynamically obtain access without static keys

For air-gapped or on-premises deployments, integrate a hardware-based security solution such as a TPM or HSM

Certain IoT devices include certified secure elements or Trusted Platform Modules that isolate cryptographic operations from the main OS

In such cases, your script interacts with a secure API provided by the hardware, not the raw credentials

Consider migrating from IMSI

While legacy cellular networks rely on USIM for authentication, newer IoT architectures favor PKI-based certificates for stronger and more scalable identity management

Ask your mobile network operator if they support certificate-based device onboarding—this removes the need to manage Ki or IMSI in software entirely

Always ensure that any system handling SIM credentials enforces least privilege access

Limit access scope to the bare minimum: one script, hackmd one credential, one session

Use short lived tokens, auto rotate keys, and monitor for unusual access patterns

Routine audits are non-negotiable for maintaining long-term security

Analyze access logs, revoke permissions for decommissioned services, purge stale credentials, and adapt policies to emerging threat intelligence

Treat SIM credentials with the same care as passwords to administrative systems or private encryption keys

When you replace hardcoded keys with dynamic secrets, enforce least privilege, and use modern authentication, your cellular devices become far more resilient to compromise