The DeFi ecosystem suffered another blow on August 14, 2023, as yield aggregator Zunami Protocol confirmed that its “zStables” liquidity pools on Curve Finance were drained through a sophisticated price manipulation exploit. Security firm PeckShield estimated losses exceeding $2.1 million, marking yet another incident in a summer plagued by decentralized finance vulnerabilities.
The Exploit Mechanics
The attacker targeted Zunami’s zStables pools, which were designed to generate optimized yields across multiple DeFi platforms. The exploit hinged on a price manipulation vector that allowed the attacker to artificially inflate the value of deposited assets before withdrawing a disproportionate share of the pool’s liquidity. By leveraging flash loan-style mechanics combined with oracle manipulation, the hacker was able to extract funds far exceeding their actual deposit value. The vulnerability lay in how Zunami’s smart contracts calculated pool share values when assets were withdrawn under manipulated market conditions.
Affected Systems
The exploit specifically impacted Zunami Protocol’s UZD and pzUSD stablecoin pools on Curve Finance. These pools aggregated yield strategies from multiple sources, including Convex Finance and other Ethereum-based DeFi protocols. The attack came at a particularly vulnerable time — Curve Finance itself had recently been exploited for approximately $41 million due to a reentrancy vulnerability in the Vyper programming language compiler. While Zunami’s exploit was technically distinct from the Curve hack, both incidents underscored the cascading risks inherent in composable DeFi architecture. At the time of the attack, Bitcoin traded at approximately $29,408 while Ethereum sat near $1,844.
The Mitigation Strategy
Following the attack, Zunami Protocol’s team immediately paused all affected pools and began coordinating with security researchers and on-chain analysts. The protocol engaged PeckShield and other blockchain security firms to conduct a thorough forensic analysis of the exploit transaction. Notably, cybersecurity firm SlowMist revealed that it had identified and reported this exact vulnerability to Zunami two months prior to the exploit — a disclosure that went unaddressed. This revelation raised serious questions about the protocol’s internal security review processes and its responsiveness to third-party vulnerability disclosures.
Lessons Learned
The Zunami exploit highlights several critical security principles that every DeFi participant should internalize. First, protocols that ignore responsible vulnerability disclosures remain sitting targets for exploitation. SlowMist’s two-month-old warning represented a missed opportunity that cost users over $2.1 million. Second, the interconnected nature of DeFi — where protocols build on top of other protocols — creates systemic risk. When Curve suffered its Vyper exploit, the shockwaves rippled through dozens of dependent projects, including Zunami. Third, price oracle manipulation remains one of the most reliable attack vectors in DeFi, and protocols that do not implement robust oracle safeguards remain perpetually exposed.
User Action Required
For users who had funds deposited in Zunami’s zStables pools, the immediate priority is to monitor official Zunami Protocol communications for recovery plans and potential compensation frameworks. More broadly, this incident serves as a stark reminder to evaluate not just a protocol’s own code but also its dependencies. Users should prefer platforms that have undergone multiple independent audits, maintain active bug bounty programs, and demonstrate a track record of promptly addressing disclosed vulnerabilities. The difference between a $2.1 million loss and a prevented attack often comes down to whether a protocol takes security warnings seriously.
Disclaimer: This article is for informational purposes only and does not constitute financial advice. Always conduct your own research before investing in or interacting with DeFi protocols.
flash loan plus oracle manipulation in august 2023. bZx got rekt the exact same way 3 years earlier. no lessons learned
flash loan plus oracle manipulation on a Curve pool is the oldest trick in the book. Zunami should have learned from Cream and Beanstalk
flash loan + oracle manipulation is such a classic combo at this point. how are teams still shipping code vulnerable to this in 2023
because audits are point-in-time snapshots. the code was clean on audit day then someone modified the oracle integration three weeks later. same story every time
the zStables pools on Curve were supposed to be the safe option lol. nowhere is safe in DeFi
curve itself was fine, it was zunamis pool logic on top of curve. the distinction matters for anyone actually reading instead of panic selling
chain_surgeon_ the curve vs zunami distinction is important but try explaining that to users who just lost their stablecoins
curve pools were supposed to be the safe part of DeFi. when even the stablecoin infrastructure gets exploited you know the bar is low
Bogdan T. curve pools being safe is a myth. anything built on top of Curve inherits its oracle dependencies and Zunami clearly didnt stress test theirs
because the audit market is broken. teams pay $20k for a rubber stamp and investors treat it as real security
basenode_ flash loan plus oracle manipulation was old news by 2021. shipping this in 2023 is basically malpractice
flashloan_truther_ oracle manipulation was a known attack vector since bZx in 2020. shipping a vulnerable lending product in 2023 is just negligence at that point
bZx got rekt by the same flashloan plus oracle trick in 2020. shipping that vulnerability in August 2023 is just inexcusable
oracle_dad_ the withdraw function had no reentrancy guard. 2023 and protocols still shipping code without checks-effects-interactions. its a 5 line fix
2.1M drained from zStables and nobody batted an eye. deFi exploit fatigue is real when 7 figure hacks dont even make front page of ct anymore
the attacker inflated pool share values before withdrawing. textbook price manipulation that a simple TWAP oracle would have prevented
flash loan plus oracle manipulation on zstables pools, same exploit pattern we keep seeing every year
peckshield flagged it fast but $2.1M was already gone. real question is whether zunami even survives this reputational hit
flash loan plus oracle manipulation was a known vector since bZx in 2020. shipping this in august 2023 means zunami either didnt audit or ignored the findings
Mihai C. bZx got hit with the exact same attack 3 years earlier. there is literally a wikipedia article about flash loan attacks. no excuse
2.1M gone and peckshield caught it after the fact. the aggregator layer on top of curve was the weak link, curve pools themselves survived which is the only silver lining
zunami lost 2.1M and somehow the curve pools themselves held. the exploit was contained to the aggregator layer which is actually kind of impressive risk isolation
stable_sweep those curve pools staying intact after the hit is actually impressive risk isolation
PeckShield caught it fast but 2.1M was already gone. Zunami never really recovered reputationally after this
Sasha Volkov. peckshield caught it after 2.1M was gone. the aggregator layer on curve is where the risk lives, not curve itself
sasha volkov peckshield spotted it quick but the 2.1m was already gone, reputation never recovered