feat(security): address findings from v2 security assessment

- L2: Add server_tokens off to nginx configs to hide version
- M1: Add X-Frame-Options, X-Content-Type-Options, Referrer-Policy,
  Permissions-Policy headers to all nginx routes
- L3: Add global NoCacheInterceptor (Cache-Control: no-store) on all
  API responses to prevent caching of sensitive financial data
- C1: Disable open registration by default (ALLOW_OPEN_REGISTRATION env)
- H3: Add logout endpoint with correct HTTP 200 status code
- M2: Implement full password reset flow (forgot-password, reset-password,
  change-password) with hashed tokens, 15-min expiry, single-use
- Reduce JWT access token expiry from 24h to 1h
- Add EmailService stub (logs to shared.email_log)
- Add DB migration 016 for password_reset_tokens table

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/app.module.ts

@@ -1,5 +1,5 @@
 import { Module, MiddlewareConsumer, NestModule } from '@nestjs/common';
-import { APP_GUARD } from '@nestjs/core';
+import { APP_GUARD, APP_INTERCEPTOR } from '@nestjs/core';
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import { TypeOrmModule } from '@nestjs/typeorm';
 import { ThrottlerModule } from '@nestjs/throttler';
@@ -7,6 +7,7 @@ import { AppController } from './app.controller';
 import { DatabaseModule } from './database/database.module';
 import { TenantMiddleware } from './database/tenant.middleware';
 import { WriteAccessGuard } from './common/guards/write-access.guard';
+import { NoCacheInterceptor } from './common/interceptors/no-cache.interceptor';
 import { AuthModule } from './modules/auth/auth.module';
 import { OrganizationsModule } from './modules/organizations/organizations.module';
 import { UsersModule } from './modules/users/users.module';
@@ -29,6 +30,7 @@ import { AttachmentsModule } from './modules/attachments/attachments.module';
 import { InvestmentPlanningModule } from './modules/investment-planning/investment-planning.module';
 import { HealthScoresModule } from './modules/health-scores/health-scores.module';
 import { BoardPlanningModule } from './modules/board-planning/board-planning.module';
+import { EmailModule } from './modules/email/email.module';
 import { ScheduleModule } from '@nestjs/schedule';
 
 @Module({
@@ -81,6 +83,7 @@ import { ScheduleModule } from '@nestjs/schedule';
     InvestmentPlanningModule,
     HealthScoresModule,
     BoardPlanningModule,
+    EmailModule,
     ScheduleModule.forRoot(),
   ],
   controllers: [AppController],
@@ -89,6 +92,10 @@ import { ScheduleModule } from '@nestjs/schedule';
       provide: APP_GUARD,
       useClass: WriteAccessGuard,
     },
+    {
+      provide: APP_INTERCEPTOR,
+      useClass: NoCacheInterceptor,
+    },
   ],
 })
 export class AppModule implements NestModule {

backend/src/common/interceptors/no-cache.interceptor.ts

@@ -0,0 +1,16 @@
+import { Injectable, NestInterceptor, ExecutionContext, CallHandler } from '@nestjs/common';
+import { Observable } from 'rxjs';
+
+/**
+ * Prevents browsers and proxies from caching authenticated API responses
+ * containing sensitive financial data (account balances, transactions, PII).
+ */
+@Injectable()
+export class NoCacheInterceptor implements NestInterceptor {
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    const res = context.switchToHttp().getResponse();
+    res.setHeader('Cache-Control', 'no-store, no-cache, must-revalidate, private');
+    res.setHeader('Pragma', 'no-cache');
+    return next.handle();
+  }
+}

backend/src/modules/auth/auth.controller.ts

@@ -6,6 +6,9 @@ import {
   UseGuards,
   Request,
   Get,
+  HttpCode,
+  ForbiddenException,
+  BadRequestException,
 } from '@nestjs/common';
 import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { AuthGuard } from '@nestjs/passport';
@@ -17,15 +20,22 @@ import { SwitchOrgDto } from './dto/switch-org.dto';
 import { JwtAuthGuard } from './guards/jwt-auth.guard';
 import { AllowViewer } from '../../common/decorators/allow-viewer.decorator';
 
+const isOpenRegistration = process.env.ALLOW_OPEN_REGISTRATION === 'true';
+
 @ApiTags('auth')
 @Controller('auth')
 export class AuthController {
   constructor(private authService: AuthService) {}
 
   @Post('register')
-  @ApiOperation({ summary: 'Register a new user' })
+  @ApiOperation({ summary: 'Register a new user (disabled unless ALLOW_OPEN_REGISTRATION=true)' })
   @Throttle({ default: { limit: 5, ttl: 60000 } })
   async register(@Body() dto: RegisterDto) {
+    if (!isOpenRegistration) {
+      throw new ForbiddenException(
+        'Open registration is disabled. Please use an invitation link to create your account.',
+      );
+    }
     return this.authService.register(dto);
   }
 
@@ -39,6 +49,16 @@ export class AuthController {
     return this.authService.login(req.user, ip, ua);
   }
 
+  @Post('logout')
+  @ApiOperation({ summary: 'Logout (invalidate current session)' })
+  @HttpCode(200)
+  @ApiBearerAuth()
+  @UseGuards(JwtAuthGuard)
+  async logout(@Request() req: any) {
+    await this.authService.logout(req.user.sub);
+    return { success: true };
+  }
+
   @Get('profile')
   @ApiOperation({ summary: 'Get current user profile' })
   @ApiBearerAuth()
@@ -67,4 +87,51 @@ export class AuthController {
     const ua = req.headers['user-agent'];
     return this.authService.switchOrganization(req.user.sub, dto.organizationId, ip, ua);
   }
+
+  // ─── Password Reset Flow ──────────────────────────────────────────
+
+  @Post('forgot-password')
+  @ApiOperation({ summary: 'Request a password reset email' })
+  @HttpCode(200)
+  @Throttle({ default: { limit: 3, ttl: 60000 } })
+  async forgotPassword(@Body() body: { email: string }) {
+    if (!body.email) throw new BadRequestException('Email is required');
+    await this.authService.requestPasswordReset(body.email);
+    // Always return same message to prevent account enumeration
+    return { message: 'If that email exists, a password reset link has been sent.' };
+  }
+
+  @Post('reset-password')
+  @ApiOperation({ summary: 'Reset password using a reset token' })
+  @HttpCode(200)
+  @Throttle({ default: { limit: 5, ttl: 60000 } })
+  async resetPassword(@Body() body: { token: string; newPassword: string }) {
+    if (!body.token || !body.newPassword) {
+      throw new BadRequestException('Token and newPassword are required');
+    }
+    if (body.newPassword.length < 8) {
+      throw new BadRequestException('Password must be at least 8 characters');
+    }
+    await this.authService.resetPassword(body.token, body.newPassword);
+    return { message: 'Password updated successfully.' };
+  }
+
+  @Patch('change-password')
+  @ApiOperation({ summary: 'Change password (authenticated)' })
+  @ApiBearerAuth()
+  @UseGuards(JwtAuthGuard)
+  @AllowViewer()
+  async changePassword(
+    @Request() req: any,
+    @Body() body: { currentPassword: string; newPassword: string },
+  ) {
+    if (!body.currentPassword || !body.newPassword) {
+      throw new BadRequestException('currentPassword and newPassword are required');
+    }
+    if (body.newPassword.length < 8) {
+      throw new BadRequestException('Password must be at least 8 characters');
+    }
+    await this.authService.changePassword(req.user.sub, body.currentPassword, body.newPassword);
+    return { message: 'Password changed successfully.' };
+  }
 }

backend/src/modules/auth/auth.module.ts

@@ -21,7 +21,7 @@ import { OrganizationsModule } from '../organizations/organizations.module';
       inject: [ConfigService],
       useFactory: (configService: ConfigService) => ({
         secret: configService.get<string>('JWT_SECRET'),
-        signOptions: { expiresIn: '24h' },
+        signOptions: { expiresIn: '1h' },
       }),
     }),
   ],

backend/src/modules/auth/auth.service.ts

@@ -4,21 +4,33 @@ import {
   ConflictException,
   ForbiddenException,
   NotFoundException,
+  BadRequestException,
+  Logger,
 } from '@nestjs/common';
 import { JwtService } from '@nestjs/jwt';
+import { ConfigService } from '@nestjs/config';
 import { DataSource } from 'typeorm';
 import * as bcrypt from 'bcryptjs';
+import { randomBytes, createHash } from 'crypto';
 import { UsersService } from '../users/users.service';
+import { EmailService } from '../email/email.service';
 import { RegisterDto } from './dto/register.dto';
 import { User } from '../users/entities/user.entity';
 
 @Injectable()
 export class AuthService {
+  private readonly logger = new Logger(AuthService.name);
+  private readonly appUrl: string;
+
   constructor(
     private usersService: UsersService,
     private jwtService: JwtService,
+    private configService: ConfigService,
     private dataSource: DataSource,
-  ) {}
+    private emailService: EmailService,
+  ) {
+    this.appUrl = this.configService.get<string>('APP_URL') || 'http://localhost:5173';
+  }
 
   async register(dto: RegisterDto) {
     const existing = await this.usersService.findByEmail(dto.email);
@@ -75,6 +87,14 @@ export class AuthService {
     return this.generateTokenResponse(u);
   }
 
+  /**
+   * Logout — currently a no-op on the server since JWT is stateless.
+   * When refresh tokens are added, this should revoke the refresh token.
+   */
+  async logout(_userId: string): Promise<void> {
+    // Placeholder for refresh token revocation
+  }
+
   async getProfile(userId: string) {
     const user = await this.usersService.findByIdWithOrgs(userId);
     if (!user) {
@@ -139,6 +159,105 @@ export class AuthService {
     await this.usersService.markIntroSeen(userId);
   }
 
+  // ─── Password Reset Flow ──────────────────────────────────────────
+
+  /**
+   * Request a password reset. Generates a token, stores its hash, and sends an email.
+   * Silently succeeds even if the email doesn't exist (prevents enumeration).
+   */
+  async requestPasswordReset(email: string): Promise<void> {
+    const user = await this.usersService.findByEmail(email);
+    if (!user) {
+      // Silently return — don't reveal whether the account exists
+      return;
+    }
+
+    // Invalidate any existing reset tokens for this user
+    await this.dataSource.query(
+      `UPDATE shared.password_reset_tokens SET used_at = NOW()
+       WHERE user_id = $1 AND used_at IS NULL`,
+      [user.id],
+    );
+
+    // Generate a 64-byte random token
+    const rawToken = randomBytes(64).toString('base64url');
+    const tokenHash = createHash('sha256').update(rawToken).digest('hex');
+    const expiresAt = new Date(Date.now() + 15 * 60 * 1000); // 15 minutes
+
+    await this.dataSource.query(
+      `INSERT INTO shared.password_reset_tokens (user_id, token_hash, expires_at)
+       VALUES ($1, $2, $3)`,
+      [user.id, tokenHash, expiresAt],
+    );
+
+    const resetUrl = `${this.appUrl}/reset-password?token=${rawToken}`;
+    await this.emailService.sendPasswordResetEmail(user.email, resetUrl);
+  }
+
+  /**
+   * Reset password using a valid reset token.
+   */
+  async resetPassword(rawToken: string, newPassword: string): Promise<void> {
+    const tokenHash = createHash('sha256').update(rawToken).digest('hex');
+
+    const rows = await this.dataSource.query(
+      `SELECT id, user_id, expires_at, used_at
+       FROM shared.password_reset_tokens
+       WHERE token_hash = $1`,
+      [tokenHash],
+    );
+
+    if (rows.length === 0) {
+      throw new BadRequestException('Invalid or expired reset token');
+    }
+
+    const record = rows[0];
+
+    if (record.used_at) {
+      throw new BadRequestException('This reset link has already been used');
+    }
+
+    if (new Date(record.expires_at) < new Date()) {
+      throw new BadRequestException('This reset link has expired');
+    }
+
+    // Update password
+    const passwordHash = await bcrypt.hash(newPassword, 12);
+    await this.dataSource.query(
+      `UPDATE shared.users SET password_hash = $1, updated_at = NOW() WHERE id = $2`,
+      [passwordHash, record.user_id],
+    );
+
+    // Mark token as used
+    await this.dataSource.query(
+      `UPDATE shared.password_reset_tokens SET used_at = NOW() WHERE id = $1`,
+      [record.id],
+    );
+  }
+
+  /**
+   * Change password for an authenticated user (requires current password).
+   */
+  async changePassword(userId: string, currentPassword: string, newPassword: string): Promise<void> {
+    const user = await this.usersService.findById(userId);
+    if (!user || !user.passwordHash) {
+      throw new UnauthorizedException('User not found');
+    }
+
+    const isValid = await bcrypt.compare(currentPassword, user.passwordHash);
+    if (!isValid) {
+      throw new UnauthorizedException('Current password is incorrect');
+    }
+
+    const passwordHash = await bcrypt.hash(newPassword, 12);
+    await this.dataSource.query(
+      `UPDATE shared.users SET password_hash = $1, updated_at = NOW() WHERE id = $2`,
+      [passwordHash, userId],
+    );
+  }
+
+  // ─── Private Helpers ──────────────────────────────────────────────
+
   private async recordLoginHistory(
     userId: string,
     organizationId: string | null,

backend/src/modules/email/email.module.ts

@@ -0,0 +1,9 @@
+import { Module, Global } from '@nestjs/common';
+import { EmailService } from './email.service';
+
+@Global()
+@Module({
+  providers: [EmailService],
+  exports: [EmailService],
+})
+export class EmailModule {}

backend/src/modules/email/email.service.ts

@@ -0,0 +1,49 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { DataSource } from 'typeorm';
+
+/**
+ * Stubbed email service — logs to console and stores in shared.email_log.
+ * Replace internals with Resend/SendGrid when ready for production.
+ */
+@Injectable()
+export class EmailService {
+  private readonly logger = new Logger(EmailService.name);
+
+  constructor(private dataSource: DataSource) {}
+
+  async sendPasswordResetEmail(email: string, resetUrl: string): Promise<void> {
+    const subject = 'Reset your HOA LedgerIQ password';
+    const body = [
+      `You requested a password reset for your HOA LedgerIQ account.`,
+      ``,
+      `Click the link below to reset your password:`,
+      resetUrl,
+      ``,
+      `This link expires in 15 minutes. If you didn't request this, ignore this email.`,
+    ].join('\n');
+
+    await this.log(email, subject, body, 'password_reset', { resetUrl });
+  }
+
+  private async log(
+    toEmail: string,
+    subject: string,
+    body: string,
+    template: string,
+    metadata: Record<string, any>,
+  ): Promise<void> {
+    this.logger.log(`EMAIL STUB -> ${toEmail}`);
+    this.logger.log(`   Subject: ${subject}`);
+    this.logger.log(`   Body:\n${body}`);
+
+    try {
+      await this.dataSource.query(
+        `INSERT INTO shared.email_log (to_email, subject, body, template, metadata)
+         VALUES ($1, $2, $3, $4, $5)`,
+        [toEmail, subject, body, template, JSON.stringify(metadata)],
+      );
+    } catch (err) {
+      this.logger.warn(`Failed to log email: ${err}`);
+    }
+  }
+}

db/migrations/016-password-reset-tokens.sql

@@ -0,0 +1,25 @@
+-- Migration 016: Password Reset Tokens
+-- Adds table for password reset token storage (hashed, single-use, short-lived).
+
+CREATE TABLE IF NOT EXISTS shared.password_reset_tokens (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    user_id UUID NOT NULL REFERENCES shared.users(id) ON DELETE CASCADE,
+    token_hash VARCHAR(255) UNIQUE NOT NULL,
+    expires_at TIMESTAMPTZ NOT NULL,
+    used_at TIMESTAMPTZ,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_password_reset_tokens_hash ON shared.password_reset_tokens(token_hash);
+CREATE INDEX IF NOT EXISTS idx_password_reset_tokens_user ON shared.password_reset_tokens(user_id);
+
+-- Also ensure email_log table exists (may not exist if migration 015 hasn't been applied)
+CREATE TABLE IF NOT EXISTS shared.email_log (
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    to_email VARCHAR(255) NOT NULL,
+    subject VARCHAR(500) NOT NULL,
+    body TEXT,
+    template VARCHAR(100),
+    metadata JSONB,
+    sent_at TIMESTAMPTZ DEFAULT NOW()
+);

nginx/host-production.conf

@@ -12,6 +12,9 @@
 #
 # Replace "app.yourdomain.com" with your actual hostname throughout this file.
 
+# Hide nginx version from Server header
+server_tokens off;
+
 # --- Rate limiting ---
 # 10 requests/sec per IP for API routes (shared memory zone: 10 MB ≈ 160k IPs)
 limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
@@ -49,6 +52,12 @@ server {
     ssl_session_timeout 10m;
     add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
 
+    # Security headers — applied to all routes
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header Referrer-Policy "no-referrer" always;
+    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;
+
     # --- Proxy defaults ---
     proxy_http_version 1.1;
     proxy_set_header Host $host;

nginx/production.conf

@@ -8,6 +8,9 @@ upstream frontend {
     keepalive 16;
 }
 
+# Hide nginx version from Server header
+server_tokens off;
+
 # Shared proxy settings
 proxy_http_version 1.1;
 proxy_set_header Connection "";          # enable keepalive to upstreams
@@ -30,6 +33,12 @@ server {
     listen 80;
     server_name _;
 
+    # Security headers — applied to all routes at the nginx layer
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header Referrer-Policy "no-referrer" always;
+    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;
+
     # --- API routes → backend ---
     location /api/ {
         limit_req zone=api_limit burst=30 nodelay;