afv-library/skills/generating-apex/references/security-guide.md

538 lines
15 KiB
Markdown

# Apex Security Guide
Comprehensive guide to Apex security including CRUD/FLS enforcement, sharing rules, and SOQL injection prevention.
---
## Table of Contents
1. [CRUD and FLS (Field-Level Security)](#crud-and-fls-field-level-security)
2. [Sharing and Record Access](#sharing-and-record-access)
3. [SOQL Injection Prevention](#soql-injection-prevention)
4. [Security Checklist](#security-checklist)
---
<a id="crud-and-fls-field-level-security"></a>
## CRUD and FLS (Field-Level Security)
### API 62.0: WITH USER_MODE
**Modern approach (API 62.0+)**: Use `WITH USER_MODE` in SOQL to enforce CRUD and FLS automatically.
```apex
// ✅ GOOD: Respects user permissions
List<Account> accounts = [
SELECT Id, Name, Industry, AnnualRevenue
FROM Account
WHERE Industry = 'Technology'
WITH USER_MODE
];
```
**DML with USER_MODE**: Use `AccessLevel.USER_MODE` for Database methods to enforce CRUD/FLS on insert, update, and delete:
```apex
// ✅ GOOD: Enforces CRUD/FLS on DML operations
Database.insert(records, AccessLevel.USER_MODE);
Database.update(records, AccessLevel.USER_MODE);
Database.delete(records, AccessLevel.USER_MODE);
```
**What USER_MODE does**:
- Enforces object-level CRUD (Create, Read, Update, Delete)
- Enforces field-level security (FLS)
- Throws `System.QueryException` if user lacks access (for SOQL)
- Throws `System.DmlException` if user lacks access (for DML)
- Respects user's sharing rules (when combined with `with sharing`)
**When to use SYSTEM_MODE**:
```apex
// Only use SYSTEM_MODE when you explicitly NEED to bypass security
List<Account> accounts = [
SELECT Id, Name, Sensitive_Field__c
FROM Account
WITH SYSTEM_MODE // ⚠️ Use with caution!
];
```
**Use cases for SYSTEM_MODE**:
- Background jobs that must process all records regardless of user
- System integrations
- Administrative cleanup scripts
**ALWAYS document why SYSTEM_MODE is needed:**
```apex
// JUSTIFICATION: This batch job processes all accounts for regulatory reporting,
// regardless of user's access level. Approved by Security Team on 2025-01-01.
```
---
### Legacy Approach: Security.stripInaccessible()
**For pre-62.0 compatibility** or when you need to filter fields dynamically:
```apex
// Query all fields
List<Account> accounts = [SELECT Id, Name, Industry, AnnualRevenue FROM Account];
// Strip inaccessible fields
SObjectAccessDecision decision = Security.stripInaccessible(
AccessType.READABLE,
accounts
);
// Use stripped records
List<Account> accessibleAccounts = decision.getRecords();
// Check which fields were removed
Set<String> removedFields = decision.getRemovedFields().get('Account');
if (removedFields != null && !removedFields.isEmpty()) {
System.debug('User lacks access to fields: ' + removedFields);
}
```
**Access Types**:
- `READABLE` - Read access (for queries)
- `CREATABLE` - Create access (before insert)
- `UPDATABLE` - Update access (before update)
- `UPSERTABLE` - Upsert access
**Example: Pre-DML Check**
```apex
public static void createAccounts(List<Account> accounts) {
// Check if user can create these fields
SObjectAccessDecision decision = Security.stripInaccessible(
AccessType.CREATABLE,
accounts
);
if (!decision.getRemovedFields().isEmpty()) {
throw new SecurityException('User lacks permission to create some fields');
}
insert decision.getRecords();
}
```
---
### Manual CRUD/FLS Checks (Verbose but Explicit)
```apex
// Check object-level CRUD
if (!Schema.sObjectType.Account.isAccessible()) {
throw new SecurityException('User cannot read Accounts');
}
if (!Schema.sObjectType.Account.isCreateable()) {
throw new SecurityException('User cannot create Accounts');
}
// Check field-level security
if (!Schema.sObjectType.Account.fields.Industry.isAccessible()) {
throw new SecurityException('User cannot read Industry field');
}
if (!Schema.sObjectType.Account.fields.Industry.isUpdateable()) {
throw new SecurityException('User cannot update Industry field');
}
```
**When to use**: Legacy codebases, specific error messaging, or when you need fine-grained control.
---
## Sharing and Record Access
### Sharing Keywords
| Keyword | Behavior | When to Use |
|---------|----------|-------------|
| `with sharing` | Enforces record-level sharing | Default for user-facing code |
| `without sharing` | Bypasses record-level sharing | System operations, integrations |
| `inherited sharing` | Inherits from calling class | Utility classes, shared libraries |
**Default Rule**: If no keyword specified, class runs in `without sharing` mode (pre-API 40 behavior).
**ALWAYS specify a sharing keyword** - implicit behavior is confusing.
---
### with sharing (Recommended Default)
```apex
public with sharing class AccountService {
public static List<Account> getAccountsForUser() {
// User only sees Accounts they have access to via sharing rules
return [SELECT Id, Name FROM Account WITH USER_MODE];
}
public static void updateAccount(Account acc) {
// Throws exception if user lacks access
update acc;
}
}
```
**Use cases**:
- User-facing controllers (LWC, Aura, Visualforce)
- Service classes handling user requests
- Trigger actions that respect user context
---
### without sharing (Use Sparingly)
```apex
public without sharing class AdminService {
// JUSTIFICATION: This method is only called by system administrators
// to perform global updates. Access controlled by Custom Permission.
public static void globalAccountUpdate() {
List<Account> allAccounts = [SELECT Id, Name FROM Account];
// Process ALL accounts, ignoring sharing
}
}
```
**Use cases**:
- Background jobs
- System integrations
- Administrative operations
**Security Note**: Always add access control checks when using `without sharing`:
```apex
public without sharing class AdminService {
public static void globalUpdate() {
// Check permission before executing
if (!FeatureManagement.checkPermission('Admin_Global_Update')) {
throw new SecurityException('Requires Admin_Global_Update permission');
}
// Now safe to proceed with without sharing logic
}
}
```
---
### inherited sharing (Best for Utilities)
```apex
public inherited sharing class StringUtils {
// Inherits sharing from calling class
public static String sanitize(String input) {
return String.escapeSingleQuotes(input);
}
}
// Called from "with sharing" class → runs with sharing
// Called from "without sharing" class → runs without sharing
```
**Use cases**:
- Utility classes
- Helper methods
- Shared libraries that don't directly query records
---
### Mixing Sharing Contexts
```apex
public with sharing class UserFacingService {
public static void processAccount(Id accountId) {
// This runs WITH sharing
Account acc = [SELECT Id, Name FROM Account WHERE Id = :accountId];
// Call a without sharing method for specific operation
SystemOperations.performGlobalCheck(acc);
}
}
public without sharing class SystemOperations {
public static void performGlobalCheck(Account acc) {
// This runs WITHOUT sharing
// Can access records the original user couldn't see
}
}
```
**Pattern**: Start with `with sharing`, only escalate to `without sharing` when needed.
---
## SOQL Injection Prevention
### The Problem
**NEVER concatenate user input into SOQL strings:**
```apex
// ❌ VULNERABLE to SOQL injection
public static List<Account> searchAccounts(String userInput) {
String query = 'SELECT Id, Name FROM Account WHERE Name = \'' + userInput + '\'';
return Database.query(query);
}
// Attack: userInput = "test' OR '1'='1"
// Results in: SELECT Id, Name FROM Account WHERE Name = 'test' OR '1'='1'
// Returns ALL accounts!
```
---
### Solution 1: Bind Variables (Recommended)
```apex
// ✅ SAFE: Use bind variables
public static List<Account> searchAccounts(String userInput) {
return [SELECT Id, Name FROM Account WHERE Name = :userInput WITH USER_MODE];
}
// Even with malicious input, it's treated as a literal string
```
**Why it works**: Salesforce treats `:userInput` as a value, not executable SOQL.
---
### Solution 2: String.escapeSingleQuotes()
**When dynamic SOQL is unavoidable** (rare cases):
```apex
// ✅ SAFE: Escape user input
public static List<Account> dynamicSearch(String userInput) {
String sanitized = String.escapeSingleQuotes(userInput);
String query = 'SELECT Id, Name FROM Account WHERE Name = \'' + sanitized + '\'';
return Database.query(query);
}
```
**What it does**: Escapes single quotes (`'` → `\'`) to prevent breaking out of string literals.
**Still prefer bind variables** - escapeSingleQuotes is a backup.
---
### Solution 3: Allowlist Validation
**For field names, operators, or other dynamic query parts:**
```apex
public static List<Account> sortedAccounts(String sortField) {
// ✅ SAFE: Validate against allowlist
Set<String> allowedFields = new Set<String>{'Name', 'Industry', 'AnnualRevenue'};
if (!allowedFields.contains(sortField)) {
throw new IllegalArgumentException('Invalid sort field');
}
String query = 'SELECT Id, Name, Industry FROM Account ORDER BY ' + sortField;
return Database.query(query);
}
```
**Use case**: Dynamic ORDER BY, dynamic field selection (but NOT WHERE clause values).
---
### Dynamic SOQL Best Practices
**Pattern: Safe Dynamic Query Builder**
```apex
public class SafeQueryBuilder {
private static final Set<String> ALLOWED_FIELDS = new Set<String>{
'Id', 'Name', 'Industry', 'AnnualRevenue'
};
private static final Set<String> ALLOWED_OPERATORS = new Set<String>{
'=', '!=', '<', '>', '<=', '>=', 'LIKE', 'IN'
};
public static List<Account> query(
String field,
String operator,
String value
) {
// Validate field
if (!ALLOWED_FIELDS.contains(field)) {
throw new IllegalArgumentException('Invalid field: ' + field);
}
// Validate operator
if (!ALLOWED_OPERATORS.contains(operator)) {
throw new IllegalArgumentException('Invalid operator: ' + operator);
}
// Use bind variable for value
String query = 'SELECT Id, Name FROM Account WHERE ' + field + ' ' + operator + ' :value WITH USER_MODE';
return Database.query(query);
}
}
```
---
## Security Checklist
Use this checklist when generating or reviewing Apex code:
### CRUD/FLS
- [ ] All SOQL queries use `WITH USER_MODE` (or `Security.stripInaccessible()` for pre-62.0)
- [ ] DML operations check `isCreateable()`, `isUpdateable()`, `isDeletable()` OR use `WITH USER_MODE`
- [ ] Custom fields have Permission Sets/Profiles granting FLS
- [ ] System operations using `WITH SYSTEM_MODE` are documented with justification
### Sharing
- [ ] All classes have explicit sharing keyword (`with sharing`, `without sharing`, or `inherited sharing`)
- [ ] User-facing classes use `with sharing`
- [ ] `without sharing` classes have documented justification
- [ ] `without sharing` classes include Custom Permission checks
### SOQL Injection
- [ ] No string concatenation in WHERE clauses with user input
- [ ] All user input uses bind variables (`:variableName`)
- [ ] Dynamic SOQL uses allowlist validation for field names/operators
- [ ] `String.escapeSingleQuotes()` used if concatenation is unavoidable
### General Security
- [ ] No hardcoded credentials or API keys (use Named Credentials)
- [ ] No hardcoded Record IDs (use Custom Metadata or queries)
- [ ] Sensitive data (SSN, PII) is encrypted at rest (Platform Encryption)
- [ ] External callouts use Named Credentials, not plain URLs
- [ ] Error messages don't leak sensitive information
---
## Advanced Security Patterns
### Custom Permissions
**Check user has specific permission before dangerous operations:**
```apex
public without sharing class DataDeletionService {
public static void deleteAllTestData() {
// Check Custom Permission
if (!FeatureManagement.checkPermission('Delete_Test_Data')) {
throw new SecurityException('Requires Delete_Test_Data permission');
}
// Safe to proceed
delete [SELECT Id FROM Account WHERE Name LIKE 'TEST%'];
}
}
```
**Create Custom Permission**: Setup → Custom Permissions → New
---
### Secure Remote Actions (@AuraEnabled)
```apex
public with sharing class AccountController {
@AuraEnabled(cacheable=true)
public static List<Account> getAccounts() {
// Runs with sharing + user mode = secure
return [SELECT Id, Name FROM Account WITH USER_MODE LIMIT 50];
}
@AuraEnabled
public static void updateAccount(Account acc) {
// Verify user can update
if (!Schema.sObjectType.Account.isUpdateable()) {
throw new AuraHandledException('No update permission');
}
update acc;
}
}
```
**Security Notes**:
- Always use `with sharing` for `@AuraEnabled` methods
- Use `WITH USER_MODE` in SOQL
- Validate DML permissions before operations
- Use `AuraHandledException` for friendly error messages
---
### Platform Events Security
```apex
public with sharing class EventPublisher {
public static void publishEvent(String message) {
// Check if user can create Platform Events
if (!Schema.sObjectType.MyEvent__e.isCreateable()) {
throw new SecurityException('Cannot publish events');
}
MyEvent__e event = new MyEvent__e(
Message__c = message
);
EventBus.publish(event);
}
}
```
---
### Custom Settings for Bypass Flags
Enable admins to disable automation without code changes:
```apex
public class TriggerConfig {
private static Trigger_Settings__c settings;
public static Boolean isDisabled(String triggerName) {
if (settings == null) {
settings = Trigger_Settings__c.getInstance();
}
return settings?.Disable_All_Triggers__c == true ||
(Boolean)settings.get('Disable_' + triggerName + '__c') == true;
}
}
// Usage in trigger action
if (TriggerConfig.isDisabled('Account')) {
return;
}
```
---
## Common Security Vulnerabilities
| Vulnerability | Example | Fix |
|---------------|---------|-----|
| **SOQL Injection** | `'WHERE Name = \'' + input + '\''` | Use bind variable `:input` |
| **XSS (Cross-Site Scripting)** | Returning unsanitized HTML | Use `HTMLENCODE()` in VF or LWC escaping |
| **Insecure Direct Object Reference** | Accepting record ID from user without checking access | Query with `WITH USER_MODE`, verify in `with sharing` |
| **Hardcoded Credentials** | `String apiKey = 'abc123';` | Use Named Credentials |
| **Missing FLS** | Directly querying fields without checking | Use `WITH USER_MODE` |
| **Overly Permissive Sharing** | `without sharing` everywhere | Use `with sharing` by default |
**Back to Main**: [SKILL.md](../SKILL.md)