1. Smart Contract Layer

   • Unauthorized fund withdrawal
   • Collateral manipulation
   • Authority bypass
   • Reentrancy attacks
   • Integer overflow/underflow

2. Backend Service Layer

   • API abuse
   • Database injection
   • Transaction replay
   • DoS attacks
   • Unauthorized access

3. Infrastructure Layer

   • RPC node compromise
   • Database breach
   • Network attacks
   • Key management

Implementation:

#[account(
    seeds = [b"vault", user.key().as_ref()],
    bump = vault.bump,
)]
pub vault: Account<'info, CollateralVault>,

Security Benefits:

• Non-custodial: Users retain control via their private key
• Deterministic addresses: No address spoofing possible
• Program-controlled: Only program can sign vault operations

Attack Mitigation:

• Prevents unauthorized fund access
• No private key storage needed
• Eliminates custody risk

Implementation:

require!(
    authority.is_authorized(&caller_program),
    VaultError::ProgramNotAuthorized
);

Security Benefits:

• Whitelist-based access control
• Admin-managed authorization
• Granular permission system

Attack Mitigation:

• Prevents unauthorized lock/unlock
• Protects against malicious CPIs
• Limits blast radius of compromised programs

Implementation:

require!(
    vault.can_withdraw(amount),
    VaultError::InsufficientBalance
);

Security Benefits:

• Pre-flight checks before operations
• Prevents overdraft
• Atomic state updates

Attack Mitigation:

• Prevents double-spending
• Protects against balance manipulation
• Ensures consistency

Implementation:

self.total_balance = self.total_balance
    .checked_add(amount)
    .ok_or(error!(VaultError::Overflow))?;

Security Benefits:

• Checked arithmetic on all operations
• Explicit error handling
• No silent failures

Attack Mitigation:

• Prevents integer overflow attacks
• Protects against underflow
• Safe balance calculations

Implementation:

token::transfer(
    CpiContext::new_with_signer(
        ctx.accounts.token_program.to_account_info(),
        Transfer {
            from: vault_token_account,
            to: user_token_account,
            authority: vault.to_account_info(),
        },
        signer_seeds,
    ),
    amount,
)?;

Security Benefits:

• Explicit program invocation
• PDA-based signing
• No delegated authority

Attack Mitigation:

• Prevents unauthorized token transfers
• Secure cross-program calls
• No approval attacks

Measures:

• Parameterized queries (SQL injection prevention)
• Connection pooling with limits
• Separate database users per service
• Encrypted connections (TLS)
• Regular backups

Implementation:

sqlx::query(
    "INSERT INTO vaults (user_pubkey, vault_pubkey, total_balance) VALUES ($1, $2, $3)"
)
.bind(user_pubkey.to_string())
.bind(vault_pubkey.to_string())
.bind(total_balance)
.execute(&self.pool)
.await?;

Measures:

• Rate limiting (100 req/min)
• Input validation
• CORS configuration
• Request size limits
• Error message sanitization

Rate Limiting:

// TODO: Implement rate limiting middleware
// Example: tower-governor or custom middleware

Purpose: Detect discrepancies between on-chain and database state

Implementation:

pub async fn reconcile_vault(&self, vault_pubkey: &str) -> Result<()> {
    let on_chain_balance = self.fetch_on_chain_balance(vault_pubkey).await?;
    let db_balance = self.db.get_vault_balance(vault_pubkey).await?;
    
    if on_chain_balance != db_balance {
        self.db.log_reconciliation(
            vault_pubkey,
            db_balance,
            on_chain_balance,
            on_chain_balance - db_balance,
        ).await?;
        
        // Alert and update
        self.alert_discrepancy(vault_pubkey, on_chain_balance, db_balance);
    }
    
    Ok(())
}

Security Benefits:

• Early detection of inconsistencies
• Audit trail for investigations
• Automated correction

All operations logged:

• Vault initialization
• Deposits and withdrawals
• Lock/unlock operations
• Authority changes
• Configuration updates

Log Format:

INSERT INTO audit_trail (action, vault_pubkey, user_pubkey, details, timestamp)
VALUES ($1, $2, $3, $4, NOW())

Purpose: Time-lock mechanism to prevent instant theft

Implementation:

pub struct PendingWithdrawal {
    pub vault: Pubkey,
    pub amount: u64,
    pub requested_at: i64,
    pub executable_at: i64,  // requested_at + withdrawal_delay
    pub executed: bool,
}

Security Benefits:

• Grace period for fraud detection
• User notification window
• Emergency intervention time

Configuration:

// Set 1 hour delay
initialize_security_config(
    withdrawal_delay: 3600,  // seconds
    daily_limit: 1_000_000_000,
)

Purpose: Restrict withdrawals to approved addresses

Implementation:

require!(
    config.is_whitelisted(&destination),
    VaultError::NotWhitelisted
);

Security Benefits:

• Limits attack destination
• Reduces theft impact
• User-controlled security

Purpose: Cap maximum daily withdrawal amount

Implementation:

pub fn check_daily_limit(&mut self, amount: u64, timestamp: i64) -> Result<()> {
    let current_day = timestamp / 86400;
    
    if current_day > self.last_withdrawal_day {
        self.withdrawn_today = 0;
        self.last_withdrawal_day = current_day;
    }
    
    require!(
        self.withdrawn_today + amount <= self.daily_withdrawal_limit,
        VaultError::DailyLimitExceeded
    );
    
    self.withdrawn_today += amount;
    Ok(())
}

Security Benefits:

• Limits damage from compromised keys
• Rate-limiting for withdrawals
• Configurable per vault

Purpose: Require M-of-N signatures for withdrawals

Implementation:

pub struct MultiSigVault {
    pub vault: Pubkey,
    pub threshold: u8,        // M signatures required
    pub signers: Vec<Pubkey>, // N total signers
}

pub struct WithdrawalProposal {
    pub multi_sig_vault: Pubkey,
    pub amount: u64,
    pub approvals: Vec<Pubkey>,
    pub expires_at: i64,
}

Workflow:

1. Signer creates proposal
2. Other signers approve
3. Execute when threshold met
4. Proposal expires if not executed

Security Benefits:

• Shared custody model
• Protection against single key compromise
• Organizational controls

Purpose: Admin can halt operations during security incident

Implementation:

require!(!config.paused, VaultError::VaultPaused);

Trigger Conditions:

• Detected exploit
• Unusual activity patterns
• Scheduled maintenance

Backend Wallet:

• Stored in encrypted file
• Environment variable path
• Limited permissions (400)
• Separate keys per environment

Best Practices:

# Generate key
solana-keygen new --outfile ~/.config/solana/backend.json

# Set permissions
chmod 400 ~/.config/solana/backend.json

# Use in environment
export WALLET_PATH=~/.config/solana/backend.json

Recommendations:

• Multi-sig upgrade authority
• Separate from operational keys
• Hardware wallet storage
• Time-locked upgrades

Metrics:

• Unusual withdrawal patterns
• Large balance changes
• Failed transaction spikes
• Authorization attempts
• Reconciliation discrepancies

Alert Triggers:

// Example alert conditions
if withdrawal_amount > LARGE_WITHDRAWAL_THRESHOLD {
    alert("Large withdrawal detected", vault_pubkey, amount);
}

if failed_withdrawals > MAX_FAILED_ATTEMPTS {
    alert("Multiple failed withdrawals", vault_pubkey, count);
}

if discrepancy > DISCREPANCY_THRESHOLD {
    alert("Balance discrepancy", vault_pubkey, discrepancy);
}

Regular Reviews:

• Daily transaction summaries
• Weekly security audits
• Monthly pattern analysis
• Quarterly security assessments

1. Detection: Automated monitoring triggers alert
2. Assessment: Evaluate severity and impact
3. Containment: Emergency pause if needed
4. Eradication: Fix vulnerability
5. Recovery: Resume operations
6. Post-Mortem: Document and improve

• On-call engineer: [Contact info]
• Security team: [Contact info]
• Management escalation: [Contact info]

1. Smart Contract Audit

   • Firms: Trail of Bits, OtterSec, Neodyme
   • Focus: Anchor program, CPI safety, authority checks

2. Backend Security Review

   • API security
   • Database security
   • Infrastructure hardening

3. Penetration Testing

   • API endpoints
   • WebSocket connections
   • Rate limiting effectiveness

• Use latest Anchor version
• Enable all compiler warnings
• Comprehensive test coverage (>80%)
• Code review for all changes
• Static analysis tools
• Fuzzing for critical functions

• Separate environments (dev/staging/prod)
• Gradual rollouts
• Monitoring before full launch
• Rollback procedures
• Incident response plan
• Regular backups

• Principle of least privilege
• Key rotation schedule
• Regular security updates
• Vulnerability scanning
• Log retention policy
• Disaster recovery plan

1. RPC Dependency: Backend relies on Solana RPC nodes

   • Mitigation: Multiple RPC endpoints, fallback logic

2. Database Single Point of Failure: PostgreSQL

   • Mitigation: Replication, regular backups

3. No Built-in 2FA: API lacks two-factor authentication

   • Mitigation: Add in production deployment

4. Limited Rate Limiting: Basic implementation

   • Mitigation: Enhance with sophisticated rate limiting

• User data encrypted at rest
• TLS for data in transit
• GDPR compliance for EU users
• Data retention policies

• KYC/AML integration points
• Transaction reporting
• Audit trail requirements
• Regulatory reporting APIs

Pre-Deployment:

• Smart contract audited
• All tests passing
• Security config enabled
• Monitoring configured
• Incident response plan ready
• Key management documented
• Backup procedures tested
• Rate limiting configured

Post-Deployment:

• Monitor logs daily
• Review alerts
• Test emergency procedures
• Update documentation
• Schedule security reviews
• Track vulnerabilities
• Plan upgrades

The Collateral Vault system implements defense-in-depth security with multiple layers:

• On-chain validation and authorization
• Off-chain monitoring and reconciliation
• Advanced features for enhanced protection
• Comprehensive logging and auditing

Regular security reviews, updates, and monitoring are essential for maintaining system security.