How to Automatically Fix AWS IAM Wildcard Policies

This post was written for an earlier version of PosturaNet. Today PosturaNet fixes security group findings as reviewed Terraform PRs; S3 and IAM come next. See how it works.

IAM wildcard policy statements (e.g. Action: "*" or Principal: "*") represent a severe privilege escalation vector in AWS. Finding these policies is easy, but automatically fixing them without breaking application code requires active logic verification.

The Wildcard Privilege Escalation Threat

When a policy grants wildcard permissions to anonymous or external accounts, it effectively bypasses IAM authorization boundaries. An attacker who gains control of any session inside that boundary can execute administrative API actions like creating users, access keys, or modifying existing policies.

Using Z3 SMT Solver for Policy Safety

PosturaNet models IAM policy rules as mathematical logic statements. Using the Z3 theorem prover, we verify the policy against safety invariants:

# Logic: NOT (WildcardPrincipal AND DangerousAction)

solver.add(p_wildcard == has_wildcard)

solver.add(p_dangerous == has_dangerous)

solver.add(Or(Not(p_wildcard), Not(p_dangerous)))

assert solver.check() == sat

Automated Remediation & GitOps

When the SMT solver proves that a wildcard configuration is unsafe, PosturaNet automatically:

Synthesizes a minimal-privilege HCL policy replacement.
Opens a GitOps pull request targeting your Terraform repositories.
Enables rollback tracking to revert changes instantly if active monitoring detects routing errors.

This closed-loop verification helps small teams keep IAM hygiene up between audits without a full-time DevSecOps engineer.