implementing-api-threat-protection-with-apigee

What this skill does

# Implementing API Threat Protection with Apigee

## Overview

Google Apigee is an enterprise API management platform that provides native security policies for threat protection, including JSON and XML content validation, OAuth 2.0 enforcement, SpikeArrest rate limiting, regular expression threat protection, and Advanced API Security for detecting malicious clients and API abuse patterns. Apigee operates as a reverse proxy that intercepts all API traffic, applying security policies before requests reach backend services, effectively shielding APIs against the OWASP API Security Top 10 threats.


## When to Use

- When deploying or configuring implementing api threat protection with apigee capabilities in your environment
- When establishing security controls aligned to compliance requirements
- When building or improving security architecture for this domain
- When conducting security assessments that require this implementation

## Prerequisites

- Google Cloud Platform account with Apigee organization provisioned
- Apigee X or Apigee hybrid environment configured
- Backend API services deployed and accessible from Apigee
- Google Cloud CLI (gcloud) installed and authenticated
- OpenAPI specification for target APIs
- Understanding of Apigee proxy bundle structure

## Core Security Policies

### 1. JSON Threat Protection

Protects against JSON-based denial-of-service attacks by limiting structural depth, entry counts, and string lengths:

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<JSONThreatProtection name="JSON-Threat-Protection-1">
    <DisplayName>JSON Threat Protection</DisplayName>
    <Source>request</Source>
    <!-- Maximum nesting depth of JSON structure -->
    <ObjectEntryNameLength>50</ObjectEntryNameLength>
    <ObjectEntryCount>25</ObjectEntryCount>
    <ArrayElementCount>100</ArrayElementCount>
    <ContainerDepth>5</ContainerDepth>
    <StringValueLength>500</StringValueLength>
</JSONThreatProtection>
```

### 2. XML Threat Protection

Shields against XML bombs, XXE attacks, and oversized XML payloads:

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<XMLThreatProtection name="XML-Threat-Protection-1">
    <DisplayName>XML Threat Protection</DisplayName>
    <Source>request</Source>
    <NameLimits>
        <Element>50</Element>
        <Attribute>50</Attribute>
        <NamespacePrefix>20</NamespacePrefix>
        <ProcessingInstructionTarget>50</ProcessingInstructionTarget>
    </NameLimits>
    <ValueLimits>
        <Text>1000</Text>
        <Attribute>500</Attribute>
        <NamespaceURI>256</NamespaceURI>
        <Comment>256</Comment>
        <ProcessingInstructionData>256</ProcessingInstructionData>
    </ValueLimits>
    <StructureLimits>
        <NodeDepth>5</NodeDepth>
        <AttributeCountPerElement>5</AttributeCountPerElement>
        <NamespaceCountPerElement>3</NamespaceCountPerElement>
        <ChildCount>25</ChildCount>
    </StructureLimits>
</XMLThreatProtection>
```

### 3. Regular Expression Threat Protection

Detects SQL injection, XSS, and other injection patterns in request parameters:

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<RegularExpressionProtection name="RegEx-Threat-Protection-1">
    <DisplayName>Regex Injection Protection</DisplayName>
    <Source>request</Source>
    <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables>

    <!-- SQL Injection patterns -->
    <QueryParam name="*">
        <Pattern>[\s]*((delete)|(exec)|(drop\s*table)|(insert)|(shutdown)|(update)|(\bor\b))</Pattern>
    </QueryParam>

    <!-- XSS patterns -->
    <QueryParam name="*">
        <Pattern>[\s]*&lt;\s*script\b[^&gt;]*&gt;[^&lt;]+&lt;\s*/\s*script\s*&gt;</Pattern>
    </QueryParam>

    <!-- Header injection -->
    <Header name="*">
        <Pattern>[\r\n]</Pattern>
    </Header>

    <!-- URI path traversal -->
    <URIPath>
        <Pattern>(/\.\.)|(\.\./)</Pattern>
    </URIPath>

    <!-- JSON body injection -->
    <JSONPayload>
        <JSONPath>$.*</JSONPath>
        <Pattern>[\s]*((delete)|(exec)|(drop\s*table)|(insert)|(shutdown)|(update))</Pattern>
    </JSONPayload>
</RegularExpressionProtection>
```

### 4. SpikeArrest Policy

Prevents traffic spikes from overwhelming backend services:

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<SpikeArrest name="Spike-Arrest-1">
    <DisplayName>API Spike Arrest</DisplayName>
    <Rate>30ps</Rate> <!-- 30 per second smoothed -->
    <Identifier ref="request.header.x-api-key"/>
    <MessageWeight ref="request.header.x-request-weight"/>
    <UseEffectiveCount>true</UseEffectiveCount>
</SpikeArrest>
```

### 5. OAuth 2.0 Token Validation

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<OAuthV2 name="Verify-OAuth-Token">
    <DisplayName>Verify OAuth 2.0 Access Token</DisplayName>
    <Operation>VerifyAccessToken</Operation>
    <ExternalAuthorization>false</ExternalAuthorization>
    <ExternalAccessToken>request.header.Authorization</ExternalAccessToken>
    <SupportedGrantTypes>
        <GrantType>authorization_code</GrantType>
        <GrantType>client_credentials</GrantType>
    </SupportedGrantTypes>
    <Scope>read write</Scope>
    <GenerateResponse enabled="true"/>
</OAuthV2>
```

### 6. API Key Validation

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<VerifyAPIKey name="Verify-API-Key-1">
    <DisplayName>Verify API Key</DisplayName>
    <APIKey ref="request.header.x-api-key"/>
</VerifyAPIKey>
```

## Proxy Bundle Configuration

### Complete Secure Proxy Flow

```xml
<!-- apiproxy/proxies/default.xml -->
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ProxyEndpoint name="default">
    <PreFlow name="PreFlow">
        <Request>
            <!-- Step 1: Verify API Key or OAuth token -->
            <Step>
                <Name>Verify-OAuth-Token</Name>
            </Step>
            <!-- Step 2: Rate limiting -->
            <Step>
                <Name>Spike-Arrest-1</Name>
            </Step>
            <!-- Step 3: Threat protection -->
            <Step>
                <Name>JSON-Threat-Protection-1</Name>
                <Condition>request.header.Content-Type = "application/json"</Condition>
            </Step>
            <Step>
                <Name>XML-Threat-Protection-1</Name>
                <Condition>request.header.Content-Type = "text/xml"</Condition>
            </Step>
            <!-- Step 4: Injection prevention -->
            <Step>
                <Name>RegEx-Threat-Protection-1</Name>
            </Step>
            <!-- Step 5: CORS enforcement -->
            <Step>
                <Name>CORS-Policy</Name>
            </Step>
        </Request>
        <Response>
            <!-- Remove internal headers from response -->
            <Step>
                <Name>Remove-Internal-Headers</Name>
            </Step>
            <!-- Add security headers -->
            <Step>
                <Name>Add-Security-Headers</Name>
            </Step>
        </Response>
    </PreFlow>

    <Flows>
        <Flow name="sensitive-operations">
            <Description>Additional protection for sensitive endpoints</Description>
            <Request>
                <Step>
                    <Name>Quota-Strict</Name>
                </Step>
            </Request>
            <Condition>(proxy.pathsuffix MatchesPath "/admin/**") or
                       (proxy.pathsuffix MatchesPath "/users/*/sensitive")</Condition>
        </Flow>
    </Flows>

    <HTTPProxyConnection>
        <BasePath>/v1</BasePath>
        <VirtualHost>secure</VirtualHost>
    </HTTPProxyConnection>

    <RouteRule name="default">
        <TargetEndpoint>default</TargetEndpoint>
    </RouteRule>
</ProxyEndpoint>
```

### Security Headers Policy

```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<AssignMessage name="Add-Security-Headers">
    <DisplayName>Add Security Response Headers</DisplayName>
    <Set>
        <Headers>
            <Heade