Criticism is mounting against zkSync within the industry, particularly focusing on its Ethereum-based layer-2 scaling solution's vulnerability to Sybil attacks. Critics argue that zkSync's current measures to prevent such attacks are insufficient, especially as the platform prepares for a token airdrop. They claim zkSync's seven listed criteria for eligibility are easily bypassed by Sybil attackers while potentially excluding legitimate users.

Concerns escalated on June 11, 2024, when Mudit Gupta, Chief Information Officer at Polygon, criticized zkSync's airdrop process as highly exploitable. Adam Cochran from Cinneamhain Ventures pointed out that the eligibility criteria could be manipulated by Sybil attackers for unfair token accumulation, despite his positive view of the zkSync team.

DeFi researcher Ignas suggested that zkSync might be intentionally avoiding strict anti-Sybil measures, potentially filtering out genuine users arbitrarily. Nansen, a crypto analytics firm, clarified its role, stating they provided data on specific wallet segments like scammers and whales but did not perform anti-Sybil checks.

Reports indicate that around 135 million ZK tokens, valued at approximately $50 million, could end up in Sybil-controlled wallets. Community members, represented by Sybil Horror 6, hope zkSync will reconsider its criteria to exclude Sybils and ensure fair distribution of tokens.

Critics argue that such issues challenge the equity of token distribution and emphasize the importance of robust anti-Sybil measures to safeguard genuine users from potential attacks.

These concerns arise amid plans for zkSync to airdrop nearly 3.68 million tokens to 695,232 wallets, representing about 17.5% of the total supply. Eligibility is tied to interaction with zkSync Era and Lite networks prior to a specified snapshot date, with each eligible wallet potentially receiving up to 100,000 ZK tokens.