API Gateway Security Audit Guide: 7 Best Practices

Your API gateway needs rock-solid security. Here's exactly how to audit it and lock it down.

Quick Summary: Run these 7 critical security checks on your API gateway:

Security Check	What It Does	Why It Matters
Authentication	Check login systems	Blocks 85% of attacks
Data Protection	Test encryption	Stops data theft
Usage Limits	Set rate limits	Prevents overload
Activity Tracking	Monitor all traffic	Catches threats
Version Control	Manage API versions	Removes old vulnerabilities
Compliance	Meet security standards	Avoids fines
Gap Analysis	Find weak spots	Fixes problems early

The Hard Truth: Companies now handle 162 APIs on average - that's 82% more than last year. Each API attack costs $6.1 million. And 90% of web traffic flows through APIs.

Here's What You'll Learn:

• Step-by-step security audit process
• Real tools you can use today
• Exact settings to check
• How to fix common problems

Who Needs This:

• API developers
• Security teams
• System admins
• DevOps engineers

Skip the fluff - let's lock down your API gateway.

Related video from YouTube

Getting Ready for Security Audits

Setting Audit Boundaries

The average company manages 162 APIs, according to Salt Security's Q3 2022 data. That's why you need a clear plan for what to check.

Here's what your audit should cover:

Area	What to Check
APIs	Active endpoints, versions, data flows
Security	Auth methods, encryption, access controls
Compliance	Industry rules, legal requirements
Infrastructure	Servers, networks, storage systems

Tools and Team Members

You'll need these core tools:

Tool Type	What It Does
Static Analysis	Spots issues in API definitions
Dynamic Testing	Checks live endpoints
Monitoring	Watches API behavior
Documentation	Tracks findings and fixes

Most teams use tools like SoapUI, Rest-Assured, or Postman for testing. For monitoring, Splunk, Elastic, or Datadog work well.

Must-Have Documents

Keep these close by:

• API specs and docs
• Security policies
• Access control lists
• Previous audit reports
• Incident response plans
• Risk assessments

Who Does What

Role	Main Tasks
Security Team	Runs the audit
API Developers	Explains how things work
System Admins	Helps with access
Compliance Officers	Checks legal stuff

"We can't afford not to address this problem head-on. Regular security checks aren't optional anymore - they're a must for any company handling APIs."

Don't wait - check your API security every time you make updates or release patches. It's way easier to fix problems early.

Practice 1: Check Authentication Systems

Authentication stops unwanted API access. Here's your security audit checklist:

Token Security Checks

Check Type	What to Look For
Token Storage	HTTPS-only sending, secure storage
Token Lifecycle	When tokens expire, auto-refresh rules
Token Rotation	How often tokens change, how to cancel them
Token Validation	Checking signatures, expiration dates

OAuth Setup Check

For OAuth 2.0, focus on these two main parts:

1. Registration Process

Your system needs to handle:

• Making client IDs and secrets
• Storing credentials safely
• Changing client secrets on schedule

2. Authorization Flow

Look at these OAuth steps:

• How authorization requests work
• Getting user permission
• Trading for access tokens
• Managing resource access

User Role Controls

Access Level	Required Checks
Basic Users	Base permissions, usage limits
Admin Users	Higher access levels, activity logs
Service Accounts	API limits, usage caps
System Roles	How permissions pass down, role clashes

2FA Check

Factor Type	What to Check
Knowledge	Passwords, PINs, security questions
Possession	Physical tokens, SMS, email codes
Biometric	Fingerprints, face scans
Location	IP addresses, GPS checks

"API security is a big data problem. You need to know your data, identities, and how your app works from start to finish."

Check These MFA Points:

• Do critical endpoints need MFA?
• Can someone skip MFA through other login paths?
• What's needed to change MFA settings?
• How safe are account recovery options?

Salt Security found companies run 162 APIs on average. Each one needs these auth checks.

Practice 2: Test Data Protection

API security attacks with data protection failures cost companies $6.1 million on average. Here's how to test your API gateway's data protection:

Check Encryption Methods

Your API needs three layers of protection:

1. Transport Layer: Use TLS 1.2+ and HTTPS only
2. Storage Layer: Set up database encryption
3. Message Layer: Add perfect forward secrecy

Plus, don't forget API key management - rotate them often and store them safely.

Private Data Protection

Let's look at how Apache APISIX handles encryption. Here's a clear before-and-after:

Bad Setup (DON'T do this):

{
  "username": "foo",
  "plugins": {
    "basic-auth": {
      "password": "bar"
    }
  }
}

Good Setup (DO this):

{
  "plugins": {
    "basic-auth": {
      "password": "+kOEVUuRc5rC5ZwvvAMLwg="
    }
  }
}

Data Transfer Security

Want solid transfer security? Focus on these four areas:

What to Do	How to Do It
Certificate Pinning	Connect only to trusted certificates
Mutual TLS	Make both sides prove their identity
Forward Secrecy	Change keys every session
Input Validation	Check ALL incoming data

"The scary thing about these breaches is that the exploited APIs worked exactly as they were designed."

Storage Security Rules

Here's what you NEED to check:

• Turn on cache encryption for REST APIs
• Delete old data automatically
• Keep secure API activity logs
• Encrypt your backups

For custom domains: Don't use certificate pinning - it breaks things. Let API Gateway handle certificates for execute-api endpoints instead.

Set up CloudFront with:

• Your own SSL certificate
• TLS 1.1 minimum
• Regular security updates

Practice 3: Set Usage Limits

API rate limits protect your system from overload. Here's what you need to know:

Request Limits

Your API gateway needs these three limits:

Limit Type	Time Window	What It Does
Burst Rate	Per second	Blocks traffic spikes
Steady Rate	Per minute	Manages regular traffic
Daily Quota	Per 24 hours	Limits total daily use

Usage Quotas

Set different limits based on:

• IP address
• API key
• User account
• Endpoint type

Here's how Facebook does it:

Access Level	Requests/Hour	Daily Limit
Basic	200	4,800
Standard	3,600	86,400
Premium	36,000	864,000

DDoS Defense

Let's talk numbers: GitHub got hit with 126,900 requests PER MILLISECOND in February 2018. That's 125 GB of data EVERY SECOND.

You need these blocks in place:

• IP-based filters
• Geo-restrictions
• Pattern detection
• Auto-blacklisting

Traffic Monitoring

Keep an eye out for these red flags:

Pattern	Meaning	What to Do
Traffic spikes	Attack starting	Tighten rate limits
Failed logins	Brute force try	Block IPs
Lots of errors	API abuse	Check patterns
Weird locations	Geo-attack	Block locations

The Token Bucket Algorithm helps control traffic:

1. Users get tokens

2. API calls spend tokens

3. Tokens come back slowly

4. No tokens = no API calls

This simple system stops both accidents and attacks.

Practice 4: Track All Activity

Here's how to set up API gateway tracking that spots problems FAST.

Activity Records

You need two types of logs to catch everything:

Log Type	What It Records	Why It Matters
Access Logs	IP addresses, paths, status codes	Shows who's using your API
Execution Logs	Internal processes, errors	Helps fix technical problems

Want access logs in CloudWatch? Use this format:

{
    "requestId": "$context.requestId",
    "ip": "$context.identity.sourceIp",
    "method": "$context.httpMethod",
    "path": "$context.resourcePath",
    "status": "$context.status"
}

Log Storage

Here's what your log system NEEDS:

Rule	Details
Storage Time	Keep logs for 90 days minimum
Access Control	Only security team can view
Backup Plan	Daily backups to separate location
Format Check	Use JSON or CLF format

Live Monitoring

Keep your eyes on these numbers:

Metric	Normal Range	Action if Outside Range
Response Time	< 200ms	Check for bottlenecks
Error Rate	< 1%	Look for failed attacks
Failed Logins	< 3 per minute	Block suspicious IPs
API Calls	Within rate limits	Adjust quotas if needed

Problem Response Tracking

When something goes wrong, do this:

1. Record time and date
2. Note affected systems
3. List actions taken
4. Track resolution time
5. Document fixes applied

Use these codes to mark how bad it is:

Code	Meaning	Response Time
P1	System down	Fix within 1 hour
P2	Major feature broken	Fix within 4 hours
P3	Minor issue	Fix within 24 hours
P4	Low impact	Fix within 1 week

Check these endpoints for system health:

• GET /rest/apigateway/health - System status
• GET /rest/apigateway/health/engine - Runtime health
• GET /metrics - Usage stats

Quick tip: Make sure AmazonAPIGatewayPushToCloudWatchLogs policy is ON. Without it? No logs.

Practice 5: API Version Security

Here's how to lock down your API versions with strong security controls.

Version Control

Your API gateway needs these version settings:

Rule	Implementation
URI Path	/api/v1/resource
Header	Accept: application/json;v=2.0
Query	?apiVersion=2.0

Big players like Facebook, Airbnb, and Twitter/X pick URI path versioning. Why? It's simple to spot and use.

Old Version Removal

Here's a clear timeline to phase out old versions:

1. Active Phase (12 months)

Keep track of who's using what and plan your next moves.

2. Warning Phase (12 months)

Tell users it's time to move on with this header:

X-DEPRECATION-WARN: "This version will be removed after 2024-07-31 23:00 UTC"

3. Shutdown Phase

Pull the plug and point everyone to the new version.

Old API Security

Got APIs you need to keep around? Add these guards:

Layer	Protection
Rate Limits	Stop at 100 calls/minute
IP Rules	Only let approved IPs through
Logging	Watch every old version call
Access	Need special auth tokens

Connection Security Rules

Lock down every API connection:

Type	Rule
HTTPS	Must use TLS 1.3+
Certs	New ones every 90 days
Headers	Set up CORS and CSP
Timeouts	Cut off after 30 seconds

"APIs tend to expose more endpoints than traditional web applications, making proper and updated documentation highly important."

Pro tip: Only keep your latest three versions. When V3 launches, V0 goes away. It's that simple.

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Practice 6: Follow Security Rules

Security isn't a "nice-to-have" - it's a must. Here's what you need to know:

Legal Requirements

Your API gateway needs to meet specific laws and rules:

Requirement	What to Check
PCI DSS 4.0	- Payment data handling rules - Due by March 31, 2024 - 50+ new API security rules
Data Privacy	- User data protection - Access controls - Data storage rules
Breach Rules	- Incident response plan - User notification process - Breach documentation

Core Standards

Two main standards matter for API security:

Standard	What It Covers
ISO 27001	- Data protection focus - Information security management - Regular security audits
SOC 2	- Security controls - Processing checks - Privacy standards

Certificate Management

Don't let these expire:

Certificate	When to Update
SSL/TLS	Every 90 days
ISO 27001	Annual audit
SOC 2	Type 1: Point-in-time Type 2: 6-month review

"We can't afford not to address this problem head-on."

Security Documentation

Keep track of:

Record Type	What to Log
Audits	- Date and scope - Found issues - Fix timeline
Incidents	- Attack type - Response steps - Resolution time
Changes	- Security updates - API versions - Config changes

The numbers tell the story:

• API security breaches: $6.1M average cost
• 90% of web traffic goes through APIs
• 92% of financial companies face API security problems
• 70% see delays from API security issues

Just look at Equifax: One security slip-up in 2017 cost them $425M in fines. Don't let that be you.

Practice 7: Find Security Gaps

Here's how to catch API security problems before attackers do.

Security Tests

You need two types of tests to keep your APIs safe:

Test Type	What It Does	How Often
Static Analysis	Spots risky code patterns	During development
Dynamic Testing	Checks live APIs for holes	Weekly or bi-weekly

Attack Tests

Your testing should focus on these key areas:

Attack Type	What to Check	Tools to Use
SQL Injection	How you handle data input	APIsec
Cross-site Scripting	How you filter scripts	OWASP ZAP
Authentication Bypass	How secure your login is	Burp Suite
Rate Limiting	How you handle traffic spikes	JMeter

Risk Levels

Each problem needs a score:

Risk Level	Impact	Fix Timeline
Critical	Someone could break in	Fix in 24 hours
High	They might grab some data	Fix in 1 week
Medium	Things might slow down	Fix in 2 weeks
Low	Small issues	Fix in 1 month

Fix Problems Fast

Here's your action plan:

Step	What to Do	When
Document	Write down what's wrong	Day 1
Prioritize	Pick what to fix first	Day 1-2
Test Fix	Try your fix in staging	Day 2-3
Deploy	Push to production	Day 3-4
Verify	Make sure it worked	Day 4-5

Let's talk numbers:

• APIs handle 90% of web traffic now
• Manual tests? They take 40 hours EACH
• But automated tools work non-stop

The OWASP API Security Project says these tests catch most attacks. Run them often and you'll spot issues FAST.

Here's why it matters: Equifax skipped ONE security check. The price tag? $425M in fines.

How to Run Security Audits

Here's a breakdown of API security audit essentials:

Phase	Tasks	Time Required
Planning	Map API endpoints, set test scope	2-3 days
Discovery	Document data flows, identify threats	3-5 days
Testing	Run security tests, check vulnerabilities	5-7 days
Reporting	List issues, suggest fixes	2-3 days
Validation	Verify fixes work	2-3 days

Your audit schedule depends on what's at risk:

API Type	Audit Frequency	Why
Payment APIs	Monthly	High-risk financial data
User Data APIs	Quarterly	Personal info protection
Public APIs	Bi-annual	External access risks
Internal APIs	Annual	Limited exposure

Here's who does what:

Role	Tasks	Tools
Security Lead	Plan audits, review results	OWASP Top 10
DevOps	Run tests, fix issues	SoapUI, Rest-Assured
QA Team	Test fixes, check changes	Postman
Compliance	Check standards, write reports	Splunk, Elastic

Pick your tools based on what you need:

Need	Tool	What It Does
Real-time Detection	Traceable	Spots threats as they happen
DDoS Protection	Imperva	Blocks attack traffic
General Testing	OWASP ZAP	Tests common vulnerabilities
Log Analysis	Datadog	Tracks API behavior

"The audit process includes five key phases: Defining Scope, Discovery and Threat Modeling, Penetration Testing and Exploitation, Reporting and Remediation, and Rechecks and Validation."

Want to nail your security audit? Here's what to do:

• Map EVERY endpoint before you start
• Test in staging (not production!)
• Keep detailed test logs
• Fix critical issues in 24 hours
• Test your fixes twice

Here's a pro tip: Mix static analysis during development with weekly dynamic testing. This combo catches most issues before they become problems.

Security Audit Tools

Here's what you need to know about API security testing tools:

Tool Type	Popular Tools	Price Range	Key Features
Gateway Tools	IBM API Connect, Salt Security	$50K-350K/year	API discovery, runtime protection
Pen Testing	Astra, Probely	$1,999-5,999/year	Auto vulnerability scanning
Runtime Security	Treblle, APIsec	$500-2,200/month	Live threat detection
Testing Tools	OWASP ZAP, Postman	Free - $39/user/month	CI/CD testing

Let me break this down into the main categories:

Built-in Gateway Tools

Every API gateway includes these basic security features:

Feature	Purpose	Tool Example
Access Control	Controls who gets in	IBM API Connect
Rate Limits	Stops overload attacks	Salt Security
Threat Alerts	Catches bad actors	Noname Security
Log Tracking	Watches API behavior	Treblle

Security Add-ons

These tools give you extra protection:

Tool	Price	Main Job
Astra	$1,999/year	9,300+ security checks
Probely	$1,180/year	100+ bug scanners
APIsec	$500/month	Non-stop testing
Akto	Free	API monitoring

Connection Tools

Here's what keeps your API connections safe:

Tool	Works Best For	Top Feature
Postman	API testing	Auth checks
SoapUI	SOAP/REST APIs	Security scans
Burp Suite	Finding weak spots	Bug detection
Fiddler	Traffic checks	Request analysis

Automated Testing

Tools that do the testing for you:

Tool	What It Tests	Works With
StackHawk	Live testing	CI/CD systems
42Crunch	OpenAPI checks	DevOps tools
Escape	GraphQL scans	Cloud systems
Data Theorem	AI scanning	Git repos

"Here's why this matters: In November 2023, Kronos Research lost $26 million in crypto after hackers broke in."

Quick tip: Start with free tools like OWASP ZAP. Add paid options like Astra ($1,999/year) when you need deeper scans.

Problems and Solutions

Here's what goes wrong in API security audits - and how to fix it:

Limited Resources

Most teams don't have enough people or money for proper API security. Here's what works:

Problem	Solution	Cost
No security tools	Start with OWASP ZAP	Free
Small team	Focus on critical APIs first	$0
Limited time	Use automated scans	$500-2,000/month
No specialists	Train existing devs	$200-500/person

Technical Problems

These issues pop up in EVERY audit:

Issue	Fix	Time to Fix
Wrong WAF setup	Check WAF Web ACL exists	1-2 hours
Bad permissions	Fix IAM user roles	30 mins
Wrong API ARN	Update resource ARN	15 mins
Failed scans	Check correlation IDs	1 hour

Rule Requirements

Breaking security rules costs BIG money:

Standard	What You Need	Breaking It Costs
GDPR	Data protection	Up to €20M or 4% revenue
HIPAA	Health data safety	Up to $50K per violation
PCI DSS	Payment security	$5K-100K per month
PSD2	Banking API rules	Varies by country

Connection Problems

Here's what breaks API connections - and how to stop it:

Problem	What Can Happen	Fix It With
Bad tokens	Data theft	OAuth 2.0
No rate limits	DDoS attacks	Request caps
Weak encryption	Data leaks	SSL/TLS
Bad monitoring	Missed attacks	Live logs

"A single API breach can lead to financial losses, reputational damage, regulatory penalties, and worse."

Want proof? T-Mobile's API breach in January 2023 exposed 37 million users' data.

Start here:

• Get OWASP ZAP (it's free)
• Lock down your busiest APIs first
• Watch your traffic
• Fix those permissions NOW

Keep Security Strong

Here's how to protect your APIs after an audit:

Daily Operations

Your security needs a schedule that works:

Task	Timing	What to Check
Quick Look	Daily	Traffic spikes, login fails
Deep Check	Weekly	New code, API endpoints
Full Review	Every 3 months	System health, rules
Attack Tests	Yearly	Break-in attempts

Fix Your Rules

What to Do	When	Why
Check Threats	Weekly	Spot problems early
Update Policies	Monthly	Close security holes
Clean Up Access	Every 3 months	Drop old accounts
Test Changes	Before going live	Stop breaks

Train Your Team

Your team needs to know their stuff:

What	Who	How Long	Goal
Security Basics	Developers	4 hours	Spot common threats
API Tests	Security pros	2 days	Find weak points
Crisis Mode	Team heads	1 day	Fix problems fast
Tools	Everyone	8 hours	Watch for issues

When Things Break

Know what to do when problems hit:

Problem	First Move	Time Limit	Then What
Data Leak	Kill bad APIs	15 min	Check logs, patch holes
DDoS	Cap traffic	5 min	Block attackers
Bad Update	Go back	10 min	Fix and test code
Login Issues	Lock it down	5 min	New tokens

Each API attack costs companies about $6.1 million. That's why you need solid security after your audit.

Key Points:

• Let tools do the daily work
• Keep your emergency contacts ready
• Practice your backup plans
• Document everything

LinkedIn shows it works - they cut API problems by 37% in 2023 just by checking more often.

Conclusion

Let's break down what you NEED to know about API gateway security:

Area	What to Do	Why It Matters
Authentication	Use OAuth 2 or JWT	Blocks 85% of attacks
Data Protection	Enable HTTPS everywhere	Protects data in transit
Monitoring	Set up real-time alerts	Spots problems fast
Testing	Run weekly security scans	Gets ahead of hackers

Here's your action plan:

Step	Time Needed	Expected Result
Security Scan	2-4 hours	Find weak spots
Fix Critical Issues	1-2 days	Block main threats
Set Up Monitoring	4-6 hours	Get alert system running
Train Team	1 day	Build team knowledge

"We can't afford not to address this problem head-on."

The security landscape is changing FAST. Here's what's coming:

Trend	Impact	Action Needed
Zero Trust Model	Tighter security rules	Update access controls
AI-Based Attacks	Smarter threats	Improve monitoring
Cloud API Growth	More entry points	Upgrade gateways
New Regulations	More compliance needs	Monthly checks

The numbers tell the story:

• APIs handle 90% of web traffic now
• An API breach costs $6.1 million
• By 2030? That cost might hit $12.2 million

Bottom line: API security needs constant attention. Keep testing. Keep updating. Keep watching. That's how you stay protected.

FAQs

Does API gateway handle security?

API gateways handle basic security - but they're not enough by themselves. Here's what you get:

Security Feature	What It Does	Success Rate
Rate Limiting	Blocks volumetric attacks	Stops 54% of basic attacks
Data Protection	Encrypts data in transit	Prevents data leaks
Access Control	Manages user permissions	Controls API usage
Attack Blocking	Stops known threat patterns	Basic protection

But there's a problem:

Salt's Q3 2022 State of API Security survey shows that 54% of companies use API gateways for security. But 82% say these tools can't stop attacks on their own.

The numbers tell the story:

API Security Stats (2022)	Impact
API Traffic Growth	Up 168%
Companies with API Security Issues	94%
Companies Using Gateway Security	54%

"Security is an extremely serious and important part of any API, and as such, it should be given the importance and weight that it deserves."

You'll need these extra security layers:

• Two-Factor Authentication (2FA)
• Transport Layer Security (TLS)
• Zero-Trust Security Model
• Weekly security tests
• API traffic monitoring

Bottom line: API gateways are just ONE part of security. You need more tools to protect against OWASP API Security Top 10 threats.

Related posts

• 7 Best Practices for API Log Analysis
• API Versioning Best Practices for Backward Compatibility
• API Gateway Authentication: Security Guide
• 6 Tips to Reduce AWS API Gateway Costs