Introduction

Privix, a next-generation privacy-preserving blockchain protocol, engaged Assure DeFi to perform an Advanced Audit of its consensus, networking, and node implementation. Written in Go, the Privix codebase aimed to extend IBFT-based consensus with customizations, while supporting robust peer to peer networking and efficient blockchain storage.
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Given the systemic risks of consensus and node level vulnerabilities, Assure DeFi’s mandate was to validate safety, liveness, and data integrity while stress testing Privix against real world adversarial scenarios.

Audit Scope

Target:
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Repository: Privix Node

Commit: 6e1de94… (audited)

Fixed Commit: ea530da…

Language: Go

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Methodology:

Static Analysis: Inspection of Go code for memory safety, concurrency risks, and I/O vulnerabilities.

Manual Review: Line by line validation of consensus algorithms, RPC exposure, and key management.

Attack Simulation: Byzantine validator attacks, RPC exploitation, P2P flooding, filesystem tampering, and crash recovery.

Functional Testing: Regression and unit test verification across blockchain, IBFT, and execution layers.

Key Security Issues Identified

1. Consensus Safety Violation (IBFT Formula) ✅ Fixed

Location: consensus/pri-bft/validators.go

Issue: Used (N–1)/2 instead of (N–1)/3 for faulty nodes, allowing up to 49% Byzantine validators.

Risk: Safety of IBFT consensus compromised, enabling conflicting blocks.

Fix: Corrected formula to (N–1)/3, restoring standard IBFT guarantees.

2. Broken Proposer Selection ✅ Fixed

Location: consensus/pri-bft/validators.go

Issue: Logic failed to select and return a proposer, causing deadlocks.

Risk: Consensus stalls, enabling denial of service.

Fix: Restored proposer selection logic with modulus based picking.

3. RPC Interface Exposed Without Authentication ✅ Fixed

Location: server/server.go

Issue: JSON-RPC bound to 0.0.0.0:8545 with no auth or allowlist.

Risk: Remote attackers could drain funds or execute admin calls.

Fix: Restricted binding to 127.0.0.1:8545, added token auth, TLS certs, and method allowlisting.

4. Libp2p Flood & Message Handling Risks ✅ Fixed

Location: network/

Issue: No per peer limits or message size caps.

Risk: Malicious peers could flood nodes, triggering OOM or CPU exhaustion.

Fix: Implemented gossipsub hardening, signature verification, peer queue limits, and connection caps.

5. Predictable Random IDs in CLI ✅ Fixed

Location: command/default.go

Issue: Used math/rand with time based seeding.

Risk: Attackers could pre compute IDs, hijacking resources or sessions.

Fix: Switched to crypto/rand for cryptographically secure ID generation.

6. Insecure Local Secrets ✅ Fixed

Location: secrets/local/local.go

Issue: Secrets stored unencrypted at ~/.privix/keystore/ with world readable permissions.

Risk: Malware or local users could extract node private keys.

Fix: Encrypted storage using AES-GCM with passphrase, enforced 0600 file permissions, CLI prompts for secure setup.

7. LevelDB Atomicity & Permissions ✅ Fixed

Location: blockchain/storage/leveldb/backend.go

Issue: Lacked fsync guarantees and file permission hardening.

Risk: Crash could corrupt chain state or replay invalid blocks.

Fix: Opened LevelDB with Sync: true and improved crash recovery. Recommendation: enforce file mode 0600 (pending).

8. Dependency Vulnerabilities (Acknowledged) ⚠️

Location: go.mod

Issue: No supply chain vulnerability scanning.

Risk: CVEs in transitive dependencies could allow remote exploits.

Recommendation: Integrate govulncheck into CI/CD pipeline, pin dependencies.

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Final Status: ✅ PASS

Testing Coverage

The audit included custom Go test suites to validate blockchain operations under adversarial conditions:

Blockchain Tests: Genesis initialization, forks, reorgs, gas limit calculation, transaction recovery, and full block writes.

IBFT Consensus Tests: Timestamp calculation, proposer logic, round up validation, invalid proposal handling.

Execution Layer Tests: Fee cap validation, dynamic fee checks, invalid transaction handling.

Testing confirmed fixes and validated Privix’s chain against consensus stalls, block verification errors, and memory safety issues.

Outcome & Impact

Following remediation:

• Consensus safety was fully restored, ensuring IBFT integrity.
  
  
• RPC and P2P endpoints hardened, preventing remote exploitation.
  
  
• Secrets and storage systems now enforce cryptographic and OS level protections.
  
  
• Privix demonstrated a strong security posture, achieving a PASS status.
  
  

Impact for Privix:

• Boosted investor confidence through third party validation.
  
  
• Hardened infrastructure for mainnet readiness.
  
  
• Reduced systemic risk of catastrophic consensus or node failures.
  
  

Why This Matters

This audit illustrates Assure DeFi’s expertise beyond Solidity smart contracts:

Consensus & Node Security – Validated IBFT implementation, proposer logic, and validator safety thresholds.

Operational Security – Strengthened RPC, P2P, and filesystem practices.

Cryptographic Rigor – Ensured randomness, key storage, and encryption meet best practices.

By dissecting Privix at every layer, from consensus to execution, Assure DeFi delivered a secure, production ready protocol aligned with industry leading standards.

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