performing-aws-privilege-escalation-assessment

Performing AWS Privilege Escalation Assessment

When to Use

• When conducting authorized penetration testing of AWS IAM configurations
• When validating that IAM policies follow the principle of least privilege
• When assessing the blast radius of a compromised AWS credential
• When building security reviews for IAM role and policy changes in CI/CD pipelines
• When evaluating cross-account trust relationships for privilege escalation risks

Do not use for unauthorized testing against AWS accounts, for assessing non-IAM attack vectors (SSRF, application vulnerabilities), or as a substitute for comprehensive cloud penetration testing. Always obtain written authorization before testing.

Prerequisites

• Written authorization for privilege escalation testing in the target AWS account
• Test IAM user or role with limited permissions as the starting point
• Pacu installed (pip install pacu)
• CloudFox installed (go install github.com/BishopFox/cloudfox@latest)
• PMapper (Principal Mapper) installed (pip install principalmapper)
• AWS CLI configured with test credentials and CloudTrail logging enabled for audit trail

Workflow

Step 1: Enumerate Starting Permissions

Establish the baseline permissions of the test principal before attempting escalation.

# Get current identity
aws sts get-caller-identity

# Enumerate inline and attached policies for the current user
aws iam list-user-policies --user-name test-user
aws iam list-attached-user-policies --user-name test-user

# Get group memberships and group policies
aws iam list-groups-for-user --user-name test-user
for group in $(aws iam list-groups-for-user --user-name test-user --query 'Groups[*].GroupName' --output text); do
  echo "=== Group: $group ==="
  aws iam list-group-policies --group-name "$group"
  aws iam list-attached-group-policies --group-name "$group"
done

# Simulate specific API calls to map effective permissions
aws iam simulate-principal-policy \
  --policy-source-arn arn:aws:iam::ACCOUNT:user/test-user \
  --action-names iam:CreateUser iam:AttachUserPolicy iam:PassRole \
    lambda:CreateFunction ec2:RunInstances sts:AssumeRole \
  --query 'EvaluationResults[*].[EvalActionName,EvalDecision]' --output table

Step 2: Scan for Privilege Escalation Paths with Pacu

Use Pacu's privilege escalation scanner to identify known IAM escalation techniques.

# Start Pacu session
pacu

# Create session and set credentials
Pacu (new:session) > set_keys --key-alias privesc-test

# Enumerate IAM configuration
Pacu > run iam__enum_users_roles_policies_groups
Pacu > run iam__enum_permissions

# Run privilege escalation scanner
Pacu > run iam__privesc_scan

# The scanner checks for 21+ known escalation methods including:
# - iam:CreatePolicyVersion (create admin policy version)
# - iam:SetDefaultPolicyVersion (revert to permissive older version)
# - iam:AttachUserPolicy / iam:AttachRolePolicy (attach admin policy)
# - iam:PutUserPolicy / iam:PutRolePolicy (create inline admin policy)
# - iam:PassRole + lambda:CreateFunction (Lambda with admin role)
# - iam:PassRole + ec2:RunInstances (EC2 with admin instance profile)
# - iam:CreateLoginProfile / iam:UpdateLoginProfile (set console password)
# - iam:CreateAccessKey (create keys for other users)
# - sts:AssumeRole (assume more privileged roles)
# - glue:CreateDevEndpoint + iam:PassRole (Glue with admin role)

Step 3: Map Privilege Escalation Graphs with PMapper

Use Principal Mapper to build a graph of all IAM principals and identify escalation edges.

# Collect IAM data for graph construction
pmapper graph create --account ACCOUNT_ID

# Query for paths to admin
pmapper query 'who can do iam:AttachUserPolicy with * on *'
pmapper query 'who can do sts:AssumeRole with arn:aws:iam::ACCOUNT:role/AdminRole'

# Find all principals that can escalate to admin
pmapper analysis

# Visualize the privilege escalation graph
pmapper visualize --filetype png

# Check specific escalation paths
pmapper query 'can arn:aws:iam::ACCOUNT:user/test-user do iam:CreatePolicyVersion with *'
pmapper query 'can arn:aws:iam::ACCOUNT:user/test-user do sts:AssumeRole with arn:aws:iam::ACCOUNT:role/*'

Step 4: Test Cross-Account Role Assumption

Evaluate cross-account trust policies for misconfigured role assumptions that allow unauthorized escalation.

# List all roles and their trust policies
aws iam list-roles --query 'Roles[*].[RoleName,Arn]' --output text | while read name arn; do
  trust=$(aws iam get-role --role-name "$name" --query 'Role.AssumeRolePolicyDocument' --output json 2>/dev/null)
  # Check for wildcards or broad trust
  echo "$trust" | python3 -c "
import json, sys
doc = json.load(sys.stdin)
for stmt in doc.get('Statement', []):
    principal = stmt.get('Principal', {})
    condition = stmt.get('Condition', {})
    if isinstance(principal, dict):
        aws_princ = principal.get('AWS', '')
    else:
        aws_princ = principal
    if '*' in str(aws_princ) or 'root' in str(aws_princ):
        has_external_id = 'sts:ExternalId' in str(condition)
        has_mfa = 'aws:MultiFactorAuthPresent' in str(condition)
        print(f'ROLE: $name')
        print(f'  Principal: {aws_princ}')
        print(f'  ExternalId required: {has_external_id}')
        print(f'  MFA required: {has_mfa}')
        if not has_external_id and not has_mfa:
            print(f'  WARNING: No ExternalId or MFA condition - confused deputy risk')
" 2>/dev/null
done

# Test role assumption
aws sts assume-role \
  --role-arn arn:aws:iam::TARGET_ACCOUNT:role/CrossAccountRole \
  --role-session-name privesc-test \
  --duration-seconds 900

Step 5: Enumerate CloudFox Attack Paths

Use CloudFox to identify additional attack surfaces including resource-based policies and service-specific escalation paths.

# Run all CloudFox checks
cloudfox aws --profile target-account all-checks -o ./cloudfox-output/

# Specific privilege escalation checks
cloudfox aws --profile target-account permissions
cloudfox aws --profile target-account role-trusts
cloudfox aws --profile target-account access-keys
cloudfox aws --profile target-account env-vars  # Lambda environment variables with secrets
cloudfox aws --profile target-account instances  # EC2 with instance profiles
cloudfox aws --profile target-account endpoints  # Exposed services

Step 6: Document Findings and Remediation

Compile all discovered escalation paths with proof-of-concept steps and remediation recommendations.

# Generate a consolidated report
cat > privesc-report.md << 'EOF'
# AWS Privilege Escalation Assessment Report

## Tested Escalation Vectors

| Vector | Status | Starting Principal | Escalated To | Risk |
|--------|--------|--------------------|--------------|------|
| iam:CreatePolicyVersion | EXPLOITABLE | test-user | AdministratorAccess | Critical |
| iam:PassRole + lambda:CreateFunction | EXPLOITABLE | dev-role | LambdaAdminRole | Critical |
| sts:AssumeRole (cross-account) | EXPLOITABLE | test-user | ProdAdminRole | High |
| iam:AttachUserPolicy | BLOCKED | test-user | N/A | N/A |
| ec2:RunInstances + iam:PassRole | BLOCKED | test-user | N/A | N/A |

## Remediation
1. Apply permission boundaries to all IAM users and roles
2. Remove iam:CreatePolicyVersion from non-admin principals
3. Add sts:ExternalId condition to all cross-account role trust policies
4. Implement SCP guardrails preventing privilege escalation actions
EOF

Key Concepts

Term	Definition
IAM Privilege Escalation	Exploiting overly permissive IAM policies to gain higher-level access than originally granted to a principal
Permission Boundary	IAM policy that sets the maximum permissions a principal can have, regardless of identity-based policies attached to it
iam:PassRole	IAM action allowing a principal to pass an IAM role to an AWS service, enabling the service to act with that role's permissions
Confused Deputy	Attack where an attacker tricks a trusted service into performing actions on their behalf using cross-account role assumption without external ID validation
Service Control Policy	AWS Organizations policy that sets maximum permissions for member accounts, providing guardrails against privilege escalation
Principal Mapper	Open-source tool that models IAM principals and their escalation paths as a directed graph for analysis

Tools & Systems

• Pacu: AWS exploitation framework with 21+ privilege escalation modules for automated detection and exploitation
• Principal Mapper: Graph-based IAM analysis tool that maps escalation paths between principals
• CloudFox: AWS enumeration tool focused on identifying attack paths from an attacker's perspective
• IAM Policy Simulator: AWS-native tool for testing effective permissions against specific API actions
• AWS Access Analyzer: Service that identifies resource policies granting external access and validates IAM policy changes

Common Scenarios

Scenario: Developer Role with iam:CreatePolicyVersion Leads to Admin Access

Context: During an authorized assessment, a tester discovers that a developer role has the iam:CreatePolicyVersion permission, which allows creating a new version of any customer-managed policy with arbitrary permissions.

Approach:

1. Enumerate policies attached to the developer role using iam__enum_permissions in Pacu
2. Identify that the role can call iam:CreatePolicyVersion on its own attached policy
3. Create a new policy version with "Action": "*", "Resource": "*", "Effect": "Allow"
4. Set the new version as the default policy version
5. Verify admin access by calling iam:ListUsers, s3:ListBuckets, etc.
6. Document the escalation chain and recommend removing iam:CreatePolicyVersion and implementing permission boundaries

Pitfalls: AWS limits managed policies to 5 versions. If all 5 exist, you must delete a version before creating a new one. Always record the original default version to restore it during cleanup. Permission boundaries prevent this escalation if properly configured, so verify boundary policies before declaring a finding.

Output Format

AWS Privilege Escalation Assessment Report
=============================================
Account: 123456789012 (Production)
Assessment Date: 2026-02-23
Starting Principal: arn:aws:iam::123456789012:user/test-user
Starting Permissions: S3 read-only, Lambda invoke, EC2 describe
Authorization: Signed by CISO, engagement #PT-2026-014

ESCALATION PATHS DISCOVERED: 4

[PRIVESC-001] iam:CreatePolicyVersion -> Admin
  Severity: CRITICAL
  Starting Permission: iam:CreatePolicyVersion on policy/dev-policy
  Escalation: Created policy version 6 with Action:* Resource:*
  Time to Exploit: < 2 minutes
  Remediation: Remove iam:CreatePolicyVersion, apply permission boundary

[PRIVESC-002] iam:PassRole + lambda:CreateFunction -> LambdaAdminRole
  Severity: CRITICAL
  Starting Permission: iam:PassRole, lambda:CreateFunction
  Escalation: Created Lambda function with AdminRole, invoked to get admin credentials
  Time to Exploit: < 5 minutes
  Remediation: Restrict iam:PassRole to specific role ARNs with condition key

[PRIVESC-003] sts:AssumeRole -> Cross-Account Admin
  Severity: HIGH
  Starting Permission: sts:AssumeRole on arn:aws:iam::987654321098:role/SharedRole
  Escalation: Role trust policy allows any principal in source account
  Remediation: Add sts:ExternalId condition and restrict Principal to specific roles

TOTAL ESCALATION PATHS: 4 (2 Critical, 1 High, 1 Medium)
PERMISSION BOUNDARIES IN PLACE: 0 / 47 IAM principals
SCP GUARDRAILS BLOCKING ESCALATION: 0 / 3 tested vectors