Foom.Cash, the ’Upgraded Tornado Cash,’ Bleeds $2.3M in Major Exploit

Another privacy protocol gets its vault cracked open. The promise of an upgrade wasn't enough to stop a multi-million dollar drain.

The Illusion of Bulletproof Code

Developers pitched Foom.Cash as the next evolution—a more secure, robust successor to its infamous predecessor. The market bought the narrative, locking up value with the expectation of ironclad privacy. Then the exploit hit, bypassing the very safeguards that were supposed to make it superior. The digital heist netted the attacker a cool $2.3 million, proving once again that in crypto, 'upgraded' often just means 'a more expensive target.'

Where the Money Went

The stolen funds didn't just vanish into a void. They moved—swiftly and with purpose—through the complex maze of decentralized finance. The trail highlights the perpetual cat-and-mouse game between builders and exploiters, where a single flaw can erase millions in perceived value overnight. It's a stark reminder that liquidity, even when wrapped in promises of anonymity, is only as safe as its weakest line of code.

The Cost of Innovation at Breakneck Speed

This incident cuts to the core of DeFi's double-edged sword. The drive to innovate and iterate rapidly fuels the ecosystem's growth but also creates glaring vulnerabilities. Each new 'upgrade' or 'fork' introduces a fresh attack surface, turning the blockchain into a high-stakes proving ground where users' funds are the test tokens. It's the financial sector's wild west, but with smarter outlaws and automated sheriffs that are always one step behind.

The exploit on Foom.Cash isn't an anomaly—it's a feature of the environment. For every protocol that moons, another gets rekt, teaching the same expensive lesson: in the quest for permissionless finance, you're often just granting permission to take your money. Maybe the real upgrade needed isn't in the code, but in the assumption that any system, especially one handling millions, can ever be truly set-and-forget. The bulls keep charging, but sometimes they're just running towards the next cliff.

How did the exploit happen?

BinanceLabs-led Web3 security network, GoPlus Security, flagged the attack, reporting that an incorrect verification key configuration allowed the attacker to forge zkSNARK proofs. This allowed them to fabricate cryptographic credentials that the protocol accepted as valid and then extract large volumes of tokens from the compromised contracts.

Blockchain security platform, Certik, wrote on X, “The root cause may be the delta2==gamma2 setting of the Groth16 verifier at 0xc043865fb4D542E2bc5ed5Ed9A2F0939965671A6. This enables the exploiter to compute ‘pC’ needed for different ‘nullifierHash’ while all other inputs are the same, and repeatedly collect ZOOM tokens.”

In short, a protocol whose marketing emphasized the near-impossibility of reversing its cryptographic protections was undone by a misconfiguration.

BlockSec’s Phalcon monitoring system, which detected suspicious transactions across both networks in real time, stated that the incident appeared to be an imitation attack. The firm noted that the attack exploited the same root cause previously identified in the Veil Cash breach, which happened a few days prior.

Although it is worth mentioning that the Veil Cash breach was more limited in scale, with losses contained to a small number of ETH, reportedly 2.9 ETH.

What is Foom.Cash?

Foom.Cash positions itself as a “ZKProof-powered Private Lottery Protocol” that combines the anonymity of Zcash, which operates as a standalone privacy chain, the accessibility of Ethereum’s DeFi ecosystem, and a built-in randomized reward mechanism. 

It is touted as an upgrade to Tornado Cash and an alternative to Zcash on Ethereum. Tornado Cash was sanctioned by the US Treasury in 2022, but the department lifted its sanctions on the platform in March 2025. 

According to the platform, it processes more daily transactions than Tornado Cash, boasts over eight million dollars in liquidity, and generates annual returns of 50 to 80% for liquidity providers.

Privacy in DeFi has been experiencing renewed interest, with Zcash registering a significant price increase in recent months, and Foom.Cash sought to capitalize on that trend by offering privacy natively within Ethereum’s existing infrastructure.

The platform used a specific variant called zkSNARKs, which is one of the key ingredients behind privacy guarantees in well-established protocols such as Zcash.

What is Foom.Cash doing to recover funds and resolve the exploit?

So far, the only mention of a recovery is tied to the second transaction of about $1.83 million, which security firms report to have been part of a white-hat rescue operation.

However, the Foom.Cash team has yet to mention or acknowledge the hack. So, as of the time of writing, there is no information on the extent of the impact from the protocol or what the protocol is doing to mitigate future attacks. 

The whitehat recovery hints that the team may be working behind the scenes to recover the funds and resolve the underlying issues.

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