Horizen is a zero-knowledge-enabled network of blockchains powered by the largest node infrastructure in the industry. Blockchains built on Horizen offer a level of flexibility unmatched by others. By building on Horizen, developers have the freedom to fully customize their blockchains, including consensus type, speed, privacy, and crypto-economies. Blockchains built on Horizen can produce massive throughput without compromising decentralization.

Developers can deploy their blockchains within the ecosystem using a variety of SDKs. The first set of SDKs, Blaze and Latus, deploy blockchains based on IOHK's provably secure Ouroboros proof-of-stake protocol. Blaze offers high-speed chains that declare their own certifiers and can run up to 1,000 TPS, while Latus uses a recursive SNARK composition for full decentralization. The next set of SDKs will include EVM integration for Ethereum smart contract compatibility.

The Zen Blockchain Foundation seeks to empower and incentivize the security community to help keep the Horizen network safe for all stakeholders through testing and finding security vulnerabilities. This bug bounty program covers essential elements that characterize the Horizen blockchain platform.

The Zen Blockchain Foundation is a US non-profit organization that maintains the critical infrastructure and drives the advancement of the Horizen ecosystem. Horizen is the zero-knowledge-enabled network of blockchains. Horizen offers best-in-class tools for developers to build their own blockchains on the largest node network that enables massive throughput without compromising decentralization. The Horizen technology allows developers to choose their own consensus and speed to fully customize their blockchains and crypto-economies.

Find out more on www.horizen.io

About Zendoo: The Zendoo protocol is a completely decentralized blockchain system based on recursive SNARKs, which enable the communication between the Horizen blockchain and sidechains of different types without the need to know their internal structure.

You can find more information in our whitepaper “a zk-SNARK Verifiable Cross-Chain Transfer Protocol Enabling Decoupled and Decentralized Sidechains”: https://arxiv.org/pdf/2002.01847.pdf

Response Targets

Horizen will make a best effort to meet the following SLAs for hackers participating in our program:

| Type of Response | SLA in business days |

| ------------- | ------------- |

| First Response | 2 days |

| Time to Triage | 2 days |

| Time to Bounty | 14 days |

| Time to Resolution | depends on severity and complexity |

We’ll try to keep you informed about our progress throughout the process.

Disclosure Policy

• As this is a private program, please do not discuss this program or any vulnerabilities (even resolved ones) outside of the program without express consent from the organization.

• Follow HackerOne's disclosure guidelines.

Program Rules

• Please provide detailed reports with reproducible steps. If the report is not detailed enough to reproduce the issue, the issue will not be eligible for a reward.

• Submit one vulnerability per-report, unless you need to chain vulnerabilities to provide impact.

• When duplicates occur, we only award the first report that was received (provided that it can be fully reproduced).

• Multiple vulnerabilities caused by one underlying issue will be awarded one bounty.

• Social engineering (e.g. phishing, vishing, smishing) is prohibited.

• Make a good faith effort to avoid privacy violations, destruction of data, and interruption or degradation of our service. Only interact with accounts you own or with the explicit permission of the account holder.

• All software within the scope of this programme must be run in regtest or testnet mode.

• A PoC should be tried on the local regtest network first, and only if not feasible on regtest it should be attempted on testnet.

• Testnet funds can be retrieved from the faucet at https://heap.horizen.io/ and should be used sparingly.

Scope

The scope of the bug bounty program will not include any UI or general functionality bugs and is limited to the types of bugs listed below and the repositories listed under Test Plan:

ZEN

• Sensitive information leakage (e.g., private keys wallets, private signersSecrets, seeds, shielded transaction de-anonymization, etc), public keys are excluded from this scope

• Transaction/certificate tampering (e.g., Changing the recipient address or amount)

• Transaction/certificate replay without majority mining hashrate (e.g., double-spend)

• Transaction/certificate withholding (e.g., censorship of transactions)

• Coin supply inflation (e.g., minting more coins than intended by the emission schedule)

• Bugs that cause the service to crash (e.g., Non-network-based DoS)

• Remote code execution vulnerabilities (proof of concept required)

• Attacks that result in harm to the quality of the blockchain or linked/neighbor nodes (e.g., attacks causing DoS score increase of honest behaving neighbours, etc)

• Effective non-network-bandwidth-flooding DDoS attacks (e.g., transaction hammering, etc)

• Bugs that cause bypassing of certificates’ acceptance validation rules (e.g., certificate’s SNARK proof specifically crafted to be accepted even if it does not meet circuit’s rules of the associated verification key)

• Bugs that cause the software to behave in a different way from the expected behaviour defined in the Zendoo whitepaper (e.g., accepting certificates from a ceased sidechain, or not voiding backward transfers after having received for the same epoch another certificate with a higher quality, etc)

ZEN Test Plan

• https://github.com/HorizenOfficial/zen

• The latest release/tag is the version that is in scope

• There are multiple ways to get and run the Horizen Node (e.g., building from source, using pre-built binaries published under https://github.com/HorizenOfficial/zen/releases, using docker https://hub.docker.com/repository/docker/zencash/zen-node)

• Build instructions can be found here https://github.com/HorizenOfficial/zen#building-from-source

• The node can be run as follows if installed from deb: zen-fetch-params && zend -testnet=1

• Details for getting testnet ZEN can be found here: https://heap.horizen.io/

If you discover any other areas which may be considered as an exploitable vulnerability or harm the integrity of the blockchain or cryptoasset, please reach out to tom_h1@wearehackerone.com and we will discuss on a case-by-case basis.

Known Issues

• Any known open or closed issues on GitHub are out of scope

Out of scope vulnerabilities (if applicable)

When reporting vulnerabilities, please consider (1) attack scenario / exploitability, and (2) security impact of the bug. The following issues are considered out of scope:

• Mainnet use of software is out of scope

• Any attack requiring the majority of the mining hashrate

• Clickjacking on pages with no sensitive actions

• Cross-Site Request Forgery (CSRF) on unauthenticated forms or forms with no sensitive actions

• Attacks requiring MITM or physical access to a user's device.

• Previously known vulnerable libraries without a working Proof of Concept.

• Comma Separated Values (CSV) injection without demonstrating a vulnerability.

• Missing best practices in SSL/TLS configuration.

• Any activity that could lead to the disruption of our service (DoS).

• Content spoofing and text injection issues without showing an attack vector/without being able to modify HTML/CSS

• Rate limiting or bruteforce issues on non-authentication / local endpoints (e.g., RPCs, websocket)

• Missing best practices in Content Security Policy.

• Missing HttpOnly or Secure flags on cookies

• Missing email best practices (Invalid, incomplete or missing SPF/DKIM/DMARC records, etc.)

• Vulnerabilities only affecting users of outdated or unpatched browsers [Less than 2 stable versions behind the latest released stable version]

• Software version disclosure / Banner identification issues / Descriptive error messages or headers (e.g. stack traces, application or server errors).

• Public Zero-day vulnerabilities that have had an official patch for less than 1 month will be awarded on a case by case basis.

• Tabnabbing

• Open redirect - unless an additional security impact can be demonstrated

• Issues that require unlikely user interaction

Payments and Swag

Because we're based in the United States, we aren't able to pay bounties and/or award swag to residents or those who report vulnerabilities from a country against which the United States has trade restrictions or export sanctions as determined by the U.S. Office of Foreign Assets Control (OFAC).

Please note, that you are responsible for any local tax or customs duties (for swag) as well.

Safe Harbor

Any activities conducted in a manner consistent with this policy will be considered authorized conduct and we will not initiate legal action against you. If legal action is initiated by a third party against you in connection with activities conducted under this policy, we will take steps to make it known that your actions were conducted in compliance with this policy.

Thank you for helping keep Horizen and our users safe!