We study the feasibility, profitability, and prevalence of sandwich attacks on Ethereum rollups with private mempools. First, we extend a formal model of optimal front- and back-run sizing, relating attack profitability to victim trade volume, liquidity depth, and slippage bounds. We complement it with an execution-feasibility model that quantifies co-inclusion constraints under private mempools. Second, we examine execution constraints in the absence of builder markets: without guaranteed atomic inclusion, attackers must rely on sequencer ordering, redundant submissions, and priority fee placement, which renders sandwiching probabilistic rather than deterministic. Third, using transaction-level data from major rollups, we show that naive heuristics overstate sandwich activity. We find that the majority of flagged patterns are false positives and that the median net return for these attacks is negative. Our results suggest that sandwiching, while endemic and profitable on Ethereum L1, is rare, unprofitable, and largely absent in rollups with private mempools. These findings challenge prevailing assumptions, refine measurement of MEV in L2s, and inform the design of sequencing policies.

翻译：本研究探讨了在具有私有内存池的以太坊Rollup上进行三明治攻击的可行性、盈利性及普遍性。首先，我们扩展了最优前跑与后跑交易规模的形式化模型，将攻击盈利能力与受害者交易量、流动性深度及滑点限制相关联。我们进一步构建了执行可行性模型，用于量化私有内存池下的共包含约束。其次，我们研究了无构建者市场时的执行约束：在缺乏原子性包含保证的情况下，攻击者必须依赖定序器排序、冗余交易提交及优先费设置，这使得三明治攻击呈现概率性而非确定性。第三，基于主流Rollup的交易级数据，我们证明简单的启发式方法会高估三明治攻击活动。我们发现大多数被标记的模式实为误报，且此类攻击的中位数净收益为负。研究结果表明，尽管三明治攻击在以太坊一层网络中普遍存在且具有盈利性，但在采用私有内存池的Rollup中却极为罕见、无利可图且基本不存在。这些发现挑战了现有假设，完善了二层网络MEV的测量方法，并为定序策略设计提供了参考依据。