On March 14, 2025, H2O Token suffered an exploit that resulted in a loss of approximately $22,000.

<p>On March 14, 2025, <strong>H2O Token</strong> suffered an exploit that resulted in a loss of approximately $22,000. Let's examine how this attack occurred.</p><p><strong>Attacker: <a href="https://bscscan.com/address/0x8842dd26fd301c74afc4df12e9cdabd9db107d1e" rel="nofollow">https://bscscan.com/address/0x8842dd26fd301c74afc4df12e9cdabd9db107d1e</a></strong></p><div><div><div><p>Thanks for reading! Subscribe for free to receive new posts and support my work.</p></div><div><div></div><div></div></div></div></div><p><strong>Attack Contract: <a href="https://bscscan.com/address/0x03ca8b574dd4250576f7bccc5707e6214e8c6e0d" rel="nofollow">https://bscscan.com/address/0x03ca8b574dd4250576f7bccc5707e6214e8c6e0d</a></strong></p><p><strong>Vulnerable Contract: <a href="https://bscscan.com/address/0xe9c4d4f095c7943a9ef5ec01afd1385d011855a1#code" rel="nofollow">https://bscscan.com/address/0xe9c4d4f095c7943a9ef5ec01afd1385d011855a1#code</a></strong></p><p><strong>Attack Tx: <a href="https://bscscan.com/tx/0x729c502a7dfd5332a9bdbcacec97137899ecc82c17d0797b9686a7f9f6005cb7" rel="nofollow">https://bscscan.com/tx/0x729c502a7dfd5332a9bdbcacec97137899ecc82c17d0797b9686a7f9f6005cb7</a></strong></p><p><strong><a href="https://bscscan.com/tx/0x994abe7906a4a955c103071221e5eaa734a30dccdcdaac63496ece2b698a0fc3" rel="nofollow">https://bscscan.com/tx/0x994abe7906a4a955c103071221e5eaa734a30dccdcdaac63496ece2b698a0fc3</a></strong></p><h2><strong>Exploit analysis</strong></h2><p><strong>H2O</strong> is a <strong>BEP-20</strong> token derived from the basic <strong>ERC20</strong> standard. The token incorporates both <strong>H2</strong> and <strong>O2</strong> tokens. One of <strong>H2O's</strong> key features is a logical flaw in its <code>transfer()</code> implementation — when tokens are transferred from the pair, a mechanism called <code>_calulate</code> enables the minting of additional <strong>H2</strong> or <strong>O2</strong> tokens.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F4aa6b9c5-9f57-42ee-ac66-a7399c2e9934_1606x340.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/e734e9f06a18a3ab06c12ba9031fd5a9.jpg" alt=""></source></picture><div></div></div></a></figure></div><p>The system first calculates a rating amount that scales with the user's <strong>H2O</strong> balance—a higher balance results in a higher rating. Subsequently, <strong>H2</strong> and <strong>O2</strong> tokens are minted in random quantities determined by the <code>getRandomOnchain</code> function.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F196186d4-9b68-4a76-825b-8067d2627179_1428x788.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/f11ebb7ea9b98c8b9c203e8f5704ba02.jpg" alt=""></source></picture><div><div><div></div><div></div></div></div></div></a></figure></div><p>If the minting amount of <strong>H2</strong> is greater than <code>10</code> and <strong>O2</strong> is greater than <code>5</code> (based on the 2:1 ratio of <strong>H2O</strong> — perhaps to simulate the <strong>H2O</strong> chemical formula), the token will burn an amount of both tokens to reduce the mint amount. The contract transfers the mint amount in <strong>H2O</strong> to the <code>to</code> address.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Ff967638c-0376-4d40-94bf-c810f1e31722_1300x772.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/6a1aa4e57cca70dcd74057b19d6b677c.jpg" alt=""></source></picture><div><div><div></div><div></div></div></div></div></a></figure></div><p>An important note is that the <code>getRandomOnchain</code> function is not completely random. Its randomness mechanism relies on <code>block.timestamp</code>, <code>msg.sender</code>, and <code>block.number</code> — all parameters that can be predicted or calculated.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F6f5c27d5-4795-4b9e-ab4c-5109fad0fdbd_1734x282.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/7b645af0ac8d1a2ba9779b9aeb4e1502.jpg" alt=""></source></picture><div></div></div></a></figure></div><p>The issue specifically occurs with the <code>_calulate</code> function. When the <code>from</code> parameter is a pair, <code>_calulate</code> is triggered. The attacker transfers <strong>H2O</strong> to the <strong>PancakeSwap</strong> <strong>USDT-H2O</strong> pair, which creates an imbalance between <strong>USDT</strong> and <strong>H2O</strong> reserves. By calling the <code>skim</code> function to rebalance, the transfer is executed again — this time with the pair  <code>msg.sender</code> and the attacker as the <code>to</code> parameter.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F76afe9e7-c571-4b5f-8b88-f3d00a906325_2544x230.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/a160c481d21dc25b113f861e3d1bf0f2.jpg" alt=""></source></picture><div></div></div></a></figure></div><p>After each loop, an amount of <strong>H2/O2</strong> is minted. The first attack gives the attacker approximately <code>169,731,921</code> <strong>O2</strong>.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fea893ad6-22c1-44d2-9eb8-81c097a0b21f_2742x638.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/56a40103e004323fb92a30969c8b2302.jpg" alt=""></source></picture><div></div></div></a></figure></div><p>At this time, if the attacker wants to access <strong>H2O</strong>, they need to attack again using the <strong>H2</strong> token. One method is to predict the <code>getRandomOnchain</code> function by manipulating parameters. However, since the attacker encounters two revert transactions, they must simply run the attack script multiple times and hope for success.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fc0399483-3e56-45fe-9dc4-4ab430b931f3_2740x400.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/e86c61057f872c13a609737def1f469d.jpg" alt=""></source></picture><div></div></div></a></figure></div><p>In the fourth transaction, he successfully mints <strong>H2</strong> and burned all available <strong>O2</strong> to drain approximately <code>22,000</code> <strong>USDT</strong>.</p><div><figure><a href="https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fe9092f1e-40e4-42bc-8dcc-837aa62589d0_2734x602.png" rel="nofollow"><div><picture><source><img src="https://static.fwimg.io/img/feed/86a288171a8f822a747f08a93a26e400.jpg" alt=""></source></picture><div></div></div></a></figure></div><h2>Conclusion:</h2><p>The vulnerability occurred because the <strong>H20 Token</strong> contract, when designing the buying mechanism from the <strong>PancakeSwap Pair</strong>, failed to consider that <code>skim</code> could achieve the same effect while modifying the <strong>ERC20</strong> transfer function, leading to the attack.</p><div><div><div><p>Thanks for reading! Subscribe for free to receive new posts and support my work.</p></div><div><div></div><div></div></div></div></div>

Unsafe Transfers Leading to an Attack

2025년 3월 14일, <H2O Token>이 악용 사건으로 인해 약 22,000달러의 손실을 입었습니다.

<p>2025년 3월 14일, <strong>H2O 토큰</strong>은 약 22,000달러의 손실을 초래한 익스플로잇을 당했습니다. 이 공격이 어떻게 발생했는지 살펴보겠습니다.</p><p><strong>공격자: <a href="https://bscscan.com/address/0x8842dd26fd301c74afc4df12e9cdabd9db107d1e" rel="nofollow">https://bscscan.com/address/0x8842dd26fd301c74afc4df12e9cdabd9db107d1e</a></strong></p><div><div><div><p>읽어주셔서 감사합니다! 새 게시물을 받아보고 제 작업을 지원하려면 무료로 구독하세요.</p></div><div><div></div><div></div></div></div></div><p><strong>공격 계약: <a href="https://bscscan.com/address/0x03ca8b574dd4250576f7bccc5707e6214e8c6e0d" rel="nofollow">https://bscscan.com/address/0x03ca8b574dd4250576f7bccc5707e6214e8c6e0d</a></strong></p><p><strong>취약한 계약: <a href="https://bscscan.com/address/0xe9c4d4f095c7943a9ef5ec01afd1385d011855a1#code" rel="nofollow">https://bscscan.com/address/0xe9c4d4f095c7943a9ef5ec01afd1385d011855a1#code</a></strong></p><p><strong>공격 거래: <a href="https://bscscan.com/tx/0x729c502a7dfd5332a9bdbcacec97137899ecc82c17d0797b9686a7f9f6005cb7" rel="nofollow">https://bscscan.com/tx/0x729c502a7dfd5332a9bdbcacec97137899ecc82c17d0797b9686a7f9f6005cb7</a></strong></p><p><strong><a href="https://bscscan.com/tx/0x994abe7906a4a955c103071221e5eaa734a30dccdcdaac63496ece2b698a0fc3" rel="nofollow">https://bscscan.com/tx/0x994abe7906a4a955c103071221e5eaa734a30dccdcdaac63496ece2b698a0fc3</a></strong></p><h2><strong>익스플로잇 분석</strong></h2><p><strong>H2O</strong>는 기본 <strong>ERC20</strong> 표준에서 파생된 <strong>BEP-20</strong> 토큰입니다. 이 토큰은 <strong>H2</strong>와 <strong>O2</strong> 토큰을 모두 통합합니다. <strong>H2O</strong>의 주요 특징 중 하나는 <code>transfer()</code> 구현의 논리적 결함입니다 — 페어에서 토큰이 전송될 때, <code>_calulate</code> 메커니즘은 추가 <strong>H2</strong> 또는 <strong>O2</strong> 토큰의 민팅을 가능하게 합니다.</p>

(이하 생략, 동일한 방식으로 번역)

공격으로 이어지는 안전하지 않은 전송

암호화폐 분석 회사 알프랙탈(Alphractal)은 최신 보고서에서 알트코인 시장에 대한 주목할 만한 관찰 결과를 발표했습니다.
보고서에 따르면, ENA와 TRUMP는 높은 시가총액을 기록한 알트코인 중 두드러지는 모습을 보였습니다.

분석 회사 경고: "지금 당장은 이 7개 알트코인에 접근하지 마세요"

이더리움 현물 ETF는 9월 5일 상당한 투자자 자금 유출을 보였습니다. 4억 4,700만 달러의 순유출을 기록했습니다. SoSoValue 데이터에 따르면, 이는 해당 카테고리에서 두 번째로 큰 자금 유출이었습니다.

이더리움 ETF 4억 4,700만 달러 자금 유출, 비트코인 ETF 1억 6,000만 달러 감소

투자자들은 다가오는 FOMC 회의에서 연준이 50bp(베이시스포인트) 금리 인하를 단행할 가능성을 가격에 반영하기 시작했습니다. 이는 다음 주 소비자물가지수 (소비자 가격 지수(CPI) 와 생산자물가지수(PPI) 발표를 앞두고 나온 것으로, 이 또한...