Why Sidechains and Layer 2s Introduce New Attack Vectors for Games

A malicious or faulty sequencer (e.g., on Arbitrum, Optimism) can freeze your game by censoring transactions. Players cannot move assets or progress, causing immediate economic halt.

• Risk: Centralized failure point controls all transaction ordering.
• Impact: 100% downtime for on-chain game loops during an outage.
• Example: Arbitrum Nova sequencer stalled for ~2 hours in 2023, freezing all games on the chain.

Cross-chain asset bridges are prime targets. A bridge hack (see: Ronin Bridge, Wormhole, Poly Network) drains the game's treasury and player assets minted on the L2.

• Risk: Bridge smart contract vulnerability or validator compromise.
• Impact: Irreversible loss of all bridged in-game assets and governance tokens.
• Vector: Often exceeds $100M+ per exploit, destroying game economies.

ZK-Rollups (e.g., zkSync Era, Starknet) rely on a prover to generate validity proofs. If this system fails, the chain cannot settle to L1, stranding assets and state.

• Risk: Complex cryptographic setup or hardware failure halts finality.
• Impact: Assets are locked for days until proof generation is restored.
• Reality: Early-stage ZK tech has unproven long-term reliability under game-level load.

Validiums or certain L2s (Immutable zkEVM, Arbitrum Nova) post data off-chain. If the Data Availability layer fails, the chain cannot be reconstructed, leading to permanent state loss.

• Risk: Centralized data committee goes offline or acts maliciously.
• Impact: Permanent loss of game state and NFT provenance.
• Trade-off: This is the cost of ~90% lower fees compared to full rollups.

Game-specific appchains (e.g., using Polygon Supernets, Avalanche Subnets) often have small, centralized validator sets. A hostile actor can buy voting power to pass malicious upgrades.

• Risk: Low validator decentralization enables 51% attacks and governance capture.
• Impact: Attacker can mint infinite assets, drain treasuries, or change core game rules.
• Reality: Security scales with token value, creating a circular vulnerability for new games.

If the base layer (e.g., Ethereum) experiences a deep reorg, it can force a reorg on the L2. This rewrites recent game history, causing rollbacks of player achievements and trades.

• Risk: Inherited vulnerability from L1 consensus instability.
• Impact: Hours of gameplay reverted, breaking leaderboards and finality guarantees.
• Mitigation: L2s have ~7 day challenge periods for withdrawals, delaying true finality.

A malicious or compromised sequencer (e.g., on Arbitrum, Optimism) can censor or reorder game state transactions, enabling front-running, griefing, and asset theft. This is a single point of failure absent in decentralized L1s.

• Attack Vector: Transaction ordering manipulation.
• Impact: ~13s forced delay for censorship escape hatches, a lifetime in-game.
• Mitigation: Explore Espresso Systems or Astria for shared sequencing.

Game assets become trapped if the canonical bridge is drained or the L2's state root is challenged successfully. This breaks the in-game economy and player trust.

• Attack Vector: Bridge contract exploit or fraudulent state proof (see Nomad, Wormhole).
• Impact: $100M+ potential loss per incident, isolating game assets.
• Mitigation: Use native issuance on L2, or LayerZero / Axelar for omnichain liquidity with programmable security.

If an L2 uses an external DA layer (e.g., Celestia, EigenDA) or validium mode, players can't prove their state if the DA fails, freezing assets. This is catastrophic for persistent game worlds.

• Attack Vector: DA layer outage or withholding attack.
• Impact: Indefinite game state freeze; players cannot exit.
• Mitigation: Opt for Ethereum-calldata rollups for maximum security, or implement EigenDA with high quorums and slashing.

Games often assume instant finality on L2s, but L1 reorgs can invalidate L2 blocks, causing state rollbacks. This breaks game logic and enables double-spend exploits within the game economy.

• Attack Vector: Ethereum L1 reorg (7-block deep reorgs are possible).
• Impact: Rollback of in-game actions and transactions.
• Mitigation: Design game logic with L1 finality checkpoints; use L2s with single-slot finality (e.g., zkSync, Starknet) where possible.

Most L2s and sidechains (Polygon PoS, Arbitrum) have multi-sig admin keys for emergency upgrades. A compromised key allows an attacker to change core game contract logic, mint infinite assets, or drain treasuries.

• Attack Vector: 5-of-9 multi-sig compromise or social engineering.
• Impact: Total protocol control loss; game economy destruction.
• Mitigation: Advocate for and deploy on immutable L2 instances or those with strictly timelocked, decentralized governance (e.g., Optimism Collective).

Games using cross-chain messaging (CCIP, Wormhole, LayerZero) for interoperability rely on external oracle networks. A 2/3+1 malicious quorum can forge messages, minting illegitimate assets or triggering false in-game events.

• Attack Vector: Oracle validator set collusion or exploit.
• Impact: Infinite mint of bridged game assets, breaking scarcity.
• Mitigation: Use hyperlane's modular security with economic stakes, or implement multi-layer fallbacks with native L2 issuance as a backup.