undermybelt Implementing Google Workspace Admin Security
When to Use
- Deploying or hardening a Google Workspace environment for enterprise use
- CIS benchmark compliance assessment for Google Workspace configuration
- Protecting against business email compromise (BEC) and phishing attacks targeting Google accounts
- Implementing Data Loss Prevention controls for Gmail and Google Drive
- Restricting OAuth application access and third-party integrations
- Configuring admin account security with Advanced Protection Program enrollment
Do not use for Microsoft 365 environments; Google Workspace has distinct admin console settings and API configurations that differ from Azure AD/Entra ID controls.
Prerequisites
- Google Workspace Business Plus, Enterprise Standard, or Enterprise Plus license
- Super Admin access to the Google Admin Console (admin.google.com)
- DNS management access for SPF, DKIM, and DMARC record configuration
- Google Cloud Identity or Cloud Identity Premium for advanced security features
- FIDO2 security keys for super admin accounts (YubiKey 5 Series recommended)
Workflow
Step 1: Harden Super Admin Accounts
Secure the highest-privilege accounts in the Google Workspace tenant:
# Google Workspace Admin SDK - configure admin account security
# Using gam (Google Apps Manager) CLI tool
# List all super admin accounts for audit
gam print admins role "Super Admin" > super_admins.csv
echo "Review and minimize super admin count (recommended: 2-3 maximum)"
# Enforce Advanced Protection Program for super admins
# APP provides strongest account protections:
# - Requires FIDO2 security key for sign-in
# - Blocks third-party app access to Gmail and Drive
# - Enhanced account recovery verification
gam update user superadmin@corp.com \
advanced_protection true
# Create dedicated break-glass admin account
gam create user breakglass-admin@corp.com \
firstname "Break" lastname "Glass Admin" \
password "$(openssl rand -base64 32)" \
changepassword true \
org "/Emergency Accounts"
# Assign super admin role to break-glass account
gam create admin breakglass-admin@corp.com "Super Admin"
# Configure admin activity alerts
# Alert Center API - create alert for admin actions
cat > admin_alert_policy.json << 'EOF'
{
"alertPolicies": [
{
"name": "Super Admin Sign-In Alert",
"conditions": {
"eventType": "login",
"filterCriteria": "actor.adminRole=SUPER_ADMIN"
},
"notifications": {
"email": ["security-team@corp.com"],
"webhook": "https://siem.corp.com/webhook/google-admin"
}
},
{
"name": "Admin Role Change Alert",
"conditions": {
"eventType": "admin_role_change"
},
"notifications": {
"email": ["security-team@corp.com"]
}
}
]
}
EOF
Step 2: Enforce Phishing-Resistant Multi-Factor Authentication
Configure MFA policies that eliminate phishable authentication factors:
# Enforce 2-Step Verification for all organizational units
# Using Admin SDK Directory API
# Enable 2SV enforcement for the entire organization
gam update org "/" settings \
2sv_enforcement true \
2sv_enrollment_grace_period 14 \
2sv_new_user_enrollment_period 1
# Configure allowed 2SV methods - restrict to phishing-resistant only
# For high-security OUs: Security keys only
gam update org "/Executive" settings \
2sv_allowed_methods "SECURITY_KEY_ONLY"
# For general staff: Security keys or phone prompts (no SMS/voice)
gam update org "/" settings \
2sv_allowed_methods "SECURITY_KEY,PHONE_PROMPT" \
2sv_disallowed_methods "SMS,VOICE_CALL,BACKUP_CODES"
# Bulk check 2SV enrollment status
gam print users \
fields primaryEmail,isEnrolledIn2Sv,isEnforcedIn2Sv \
query "isEnrolledIn2Sv=false" > users_without_2sv.csv
# Count users without 2SV
echo "Users without 2SV enrolled:"
wc -l < users_without_2sv.csv
# Configure context-aware access policies
# Require 2SV + managed device for sensitive apps
cat > context_aware_policy.json << 'EOF'
{
"accessLevels": [
{
"name": "Managed Device Required",
"conditions": {
"devicePolicy": {
"requireScreenLock": true,
"requireAdminApproval": true,
"allowedEncryptionStatuses": ["ENCRYPTED"],
"requireCorpOwned": false
},
"requiredAccessLevels": ["VERIFIED_2SV"]
}
}
],
"applicationPolicies": [
{
"applications": ["Google Drive", "Gmail", "Admin Console"],
"accessLevel": "Managed Device Required"
}
]
}
EOF
Step 3: Configure Email Authentication and Anti-Phishing
Set up SPF, DKIM, DMARC and advanced phishing protections:
# Step 3a: Configure SPF record
# Add to DNS TXT record for corp.com
echo 'DNS TXT Record for SPF:'
echo 'corp.com TXT "v=spf1 include:_spf.google.com ~all"'
echo ''
echo 'After testing, change ~all to -all (hard fail) for enforcement'
# Step 3b: Generate and configure DKIM signing
# Generate 2048-bit DKIM key via Admin Console or API
gam create dkim domain corp.com selector google bitlength 2048
echo 'Add DKIM DNS TXT record:'
echo 'google._domainkey.corp.com TXT "v=DKIM1; k=rsa; p=<public_key_from_admin_console>"'
# Verify DKIM is working
gam info dkim domain corp.com
# Step 3c: Configure DMARC policy
echo 'DNS TXT Record for DMARC (start with monitoring):'
echo '_dmarc.corp.com TXT "v=DMARC1; p=none; rua=mailto:dmarc-reports@corp.com; ruf=mailto:dmarc-forensics@corp.com; pct=100; adkim=s; aspf=s"'
echo ''
echo 'After 30 days monitoring, escalate to quarantine then reject:'
echo '_dmarc.corp.com TXT "v=DMARC1; p=reject; rua=mailto:dmarc-reports@corp.com; pct=100; adkim=s; aspf=s"'
# Step 3d: Enable advanced phishing and malware protection
# Configure in Admin Console > Security > Email Safety
gam update settings email_safety \
protect_against_domain_spoofing true \
protect_against_employee_spoofing true \
protect_against_inbound_spoofing true \
protect_unauthenticated_email true \
identify_spoofed_groups true \
auto_move_suspicious_to_spam true
# Configure attachment security
gam update settings email_safety \
protect_encrypted_attachments true \
protect_anomalous_attachment_types true \
protect_scripts_from_untrusted true \
whitelist_sender_domains "" \
apply_future_recommended_settings true
Step 4: Implement Data Loss Prevention (DLP)
Configure DLP rules to prevent sensitive data exfiltration:
# Create DLP rules for Gmail and Drive
# Using Google Workspace DLP API
cat > dlp_rules.json << 'EOF'
{
"dlpRules": [
{
"name": "PII Detection - SSN",
"description": "Detect Social Security Numbers in outbound email and Drive sharing",
"trigger": {
"contentMatchers": [
{
"infoType": "US_SOCIAL_SECURITY_NUMBER",
"likelihood": "LIKELY",
"minMatchCount": 1
}
],
"scope": ["GMAIL_OUTBOUND", "DRIVE_EXTERNAL_SHARE"]
},
"action": {
"blockAction": "QUARANTINE",
"notifyAdmin": true,
"notifyUser": true,
"userMessage": "This message contains a Social Security Number and has been quarantined for review.",
"auditLog": true
}
},
{
"name": "Credit Card Number Detection",
"description": "Block credit card numbers in outbound communications",
"trigger": {
"contentMatchers": [
{
"infoType": "CREDIT_CARD_NUMBER",
"likelihood": "LIKELY",
"minMatchCount": 1
}
],
"scope": ["GMAIL_OUTBOUND", "DRIVE_EXTERNAL_SHARE", "CHAT"]
},
"action": {
"blockAction": "BLOCK",
"notifyAdmin": true,
"notifyUser": true,
"auditLog": true
}
},
{
"name": "Confidential Document Detection",
"description": "Detect documents marked as Confidential or Internal Only",
"trigger": {
"contentMatchers": [
{
"customRegex": "(?i)(CONFIDENTIAL|INTERNAL ONLY|DO NOT DISTRIBUTE|RESTRICTED)",
"minMatchCount": 2
}
],
"metadataMatchers": [
{
"driveLabels": ["Confidential", "Restricted"]
}
],
"scope": ["DRIVE_EXTERNAL_SHARE"]
},
"action": {
"blockAction": "WARN",
"requireJustification": true,
"auditLog": true
}
}
]
}
EOF
echo "Apply DLP rules via Admin Console > Security > Data Protection"
echo "Or use the Google Workspace DLP API for programmatic deployment"
Step 5: Control OAuth Applications and Third-Party Access
Restrict which third-party applications can access organizational data:
# Configure OAuth app access control
# Admin Console > Security > API Controls > App Access Control
# Block all third-party apps by default, then allowlist approved ones
gam update org "/" settings \
third_party_app_access "BLOCKED" \
allow_users_to_install_apps false
# Allowlist approved applications
cat > approved_apps.json << 'EOF'
{
"allowedApps": [
{
"appId": "slack-app-id",
"name": "Slack",
"scopes": ["gmail.readonly", "calendar.readonly"],
"approvedBy": "security-team",
"reviewDate": "2026-01-15"
},
{
"appId": "zoom-app-id",
"name": "Zoom",
"scopes": ["calendar.events"],
"approvedBy": "security-team",
"reviewDate": "2026-01-15"
},
{
"appId": "salesforce-app-id",
"name": "Salesforce",
"scopes": ["gmail.send", "contacts.readonly"],
"approvedBy": "security-team",
"reviewDate": "2026-01-15"
}
]
}
EOF
# Audit current OAuth tokens granted by users
gam all users print tokens > oauth_tokens_audit.csv
echo "Review oauth_tokens_audit.csv for unauthorized third-party access"
# Revoke tokens for unapproved applications
gam all users deprovision tokens \
clientid "unapproved-app-client-id"
# Configure API scopes restriction
# Limit which API scopes third-party apps can request
gam update org "/" settings \
api_access_restricted true \
allowed_api_scopes "gmail.readonly,calendar.readonly,drive.readonly"
Step 6: Configure External Sharing and Drive Security
Lock down data sharing controls:
# Configure Google Drive sharing restrictions
gam update org "/" settings \
drive_sharing_outside_domain "WHITELISTED_DOMAINS" \
drive_sharing_whitelisted_domains "partner1.com,partner2.com" \
drive_allow_file_requests false \
drive_shared_drive_creation "ADMIN_ONLY" \
drive_default_link_sharing "RESTRICTED"
# Configure sharing alerts
gam create alert \
name "External Sharing Alert" \
type "drive_external_share" \
condition "shared_outside_domain=true AND file_type IN ('spreadsheet','document','presentation')" \
action "notify_admin security-team@corp.com"
# Audit current external shares
gam all users print filelist \
fields id,name,owners,permissions \
query "visibility='anyoneWithLink' or visibility='anyoneCanFind'" \
> external_shares_audit.csv
echo "External shares requiring review:"
wc -l < external_shares_audit.csv
# Configure Google Groups security
gam update org "/" settings \
groups_external_members false \
groups_external_posting false \
groups_creation "ADMIN_ONLY" \
groups_allow_external_invitations false
Key Concepts
| Term | Definition |
|---|---|
| Advanced Protection Program (APP) | Google's strongest account security requiring FIDO2 security keys, blocking third-party app access, and enhanced identity verification for account recovery |
| Context-Aware Access | Security policy framework that evaluates device posture, location, and user identity before granting access to Google Workspace applications |
| DMARC | Domain-based Message Authentication, Reporting and Conformance protocol that prevents email domain spoofing by validating SPF and DKIM alignment |
| DLP Rule | Data Loss Prevention policy that scans content in Gmail, Drive, and Chat for sensitive data patterns and triggers block, quarantine, or warn actions |
| OAuth App Allowlisting | Admin control restricting which third-party applications can access organizational data through Google OAuth API scopes |
| 2-Step Verification (2SV) | Google's multi-factor authentication implementation supporting security keys, phone prompts, TOTP, and backup codes as second factors |
Tools & Systems
- Google Admin Console: Web-based administration portal for managing all Google Workspace security settings, users, and organizational units
- GAM (Google Apps Manager): Open-source command-line tool for bulk Google Workspace administration and automation
- Google Workspace Alert Center: Centralized dashboard for security alerts including suspicious login activity, DLP violations, and device compromise
- Google BeyondCorp Enterprise: Zero-trust access solution integrated with Google Workspace for context-aware access policies
Common Scenarios
Scenario: Securing a Newly Acquired Google Workspace Tenant
Context: Post-acquisition security audit reveals the acquired company's Google Workspace has no MFA enforcement, open external sharing, no DLP policies, and multiple unauthorized OAuth applications accessing user data.
Approach:
- Immediately enforce 2SV for all super admin accounts using FIDO2 security keys
- Reduce super admin count to 3 (primary, secondary, break-glass)
- Deploy SPF, DKIM, and DMARC starting with monitoring mode (p=none)
- Enable all anti-phishing and anti-spoofing settings in Email Safety
- Audit and revoke all unauthorized OAuth application tokens
- Set third-party app access to blocked with allowlist of approved applications
- Restrict external Drive sharing to approved partner domains only
- Deploy DLP rules for PII, financial data, and confidential documents
- Enable context-aware access requiring managed devices for sensitive applications
- Configure security alerts and SIEM integration for ongoing monitoring
Pitfalls:
- Enforcing MFA without enrollment grace period locks users out of accounts
- Setting DMARC to reject before monitoring period causes legitimate email delivery failures
- Blocking all OAuth apps without identifying business-critical integrations disrupts workflows
- Not auditing existing external shares before restricting sharing leaves data exposed
Output Format
GOOGLE WORKSPACE SECURITY ASSESSMENT REPORT
=============================================
Tenant: corp.com
License: Enterprise Plus
Total Users: 3,847
Organizational Units: 12
AUTHENTICATION SECURITY
2SV Enforced: YES (all OUs)
2SV Enrollment: 3,712 / 3,847 (96.5%)
Security Keys Only: Executive OU (47 users)
Advanced Protection: 3 super admin accounts
Super Admin Count: 3 (within recommended limit)
EMAIL AUTHENTICATION
SPF: CONFIGURED (hard fail: -all)
DKIM: CONFIGURED (2048-bit, selector: google)
DMARC: ENFORCED (p=reject, 100%)
Anti-Phishing: ALL PROTECTIONS ENABLED
Anti-Spoofing: ENABLED (domain + employee name)
DATA PROTECTION
DLP Rules Active: 7
PII Detection: SSN, Credit Card, Passport
Content Labels: Confidential, Restricted
Custom Patterns: 3 organization-specific rules
DLP Violations (30d): 89 (67 blocked, 22 warned)
APPLICATION CONTROL
Third-Party App Policy: BLOCKED (allowlist mode)
Approved Apps: 12
Unauthorized Tokens: 0 (all revoked)
API Scope Restrictions: ENABLED
SHARING CONTROLS
External Sharing: RESTRICTED (allowlisted domains only)
Public Link Sharing: DISABLED
External Group Members: DISABLED
Shared Drive Creation: ADMIN ONLY