A Vietnamese robot farm made up of 30,000 mobile phones: How to steal crypto airdrops from real users?

Author: Felix Ng

Compiled by: Wu Says Blockchain Aki Chen

In a "tin shed" with a refrigeration system just a 40-minute drive from Ho Chi Minh City, Mirai Labs CEO Corey Wilton first truly realized the massive scale of abuse surrounding crypto airdrops. "It's really chilling," Wilton said in an interview. He had just visited a "phone farm" in southern Vietnam, where he estimated that at least 30,000 smartphones were stacked in a room no larger than a single apartment.

For the past four years, Wilton has hoped to witness firsthand the behind-the-scenes operations that collapsed his flagship NFT racing game Pegaxy in 2021. "At that time, Pegaxy was on fire, and our daily active users peaked at around 500,000," Wilton recalled. "That's when we started receiving reports about 'robot farms'." These robots could control hundreds of accounts simultaneously, quickly purchasing racehorses with higher winning odds and repeatedly participating in races to earn in-game currency, which could then be cashed out in the real world. "You would see screenshots from people showing dozens of applications running on their screens, and similar scenes frequently appeared on social media," he explained.

Pegaxy is an automated racing game where fifteen horses compete against each other. Wilton stated that robot farms transformed the game from "who can win" to "who can extract value faster"—changing the game atmosphere and accelerating the project's decline.

On-Site: Unveiling Vietnam's "Professional" Phone Farms

In May of this year, Wilton finally got his wish, with the help of a former Pegaxy player, to exclusively visit a "highly specialized phone farm" in Vietnam. This player had stumbled upon the farm's traces on TikTok.

(Corey Wilton)

"I went to two places, both about a 40-minute drive from where I was, in relatively remote areas," he recalled. "There would definitely be no foreigners going there, and they completely do not want to be discovered." Wilton described one of the locations as a tin shed right next to the street, with the air conditioning set to "as cold as it can get."

Inside the tin shed were metal racks filled with thousands of smartphones, leaving only narrow aisles for employees to pass through. The entire layout resembled a "shoddy" crypto mining farm.

Wilton stated that the operators showed him the "leasing segment" of the business, where clients could rent the phone farm for any purpose they needed. Unlike traditional bot servers, each device in the phone farm is equipped with its own SIM card and device fingerprint, and can disguise its IP geographical location, making it harder to detect, especially in systems that require each account to be linked to a phone number. Additionally, smartphones offer a high cost-performance ratio between computing power and cost, and even if one device is damaged, it can be quickly replaced without significantly affecting overall operations.

Wilton noted that in the cases he witnessed, an operator would control a "master phone" via computer, which was connected to over 500 "slave phones." Whatever operation was performed on the master phone would be synchronized across all slave devices. "Most of their clients actually come from the Web2 industry. For example, K-pop agencies rent these devices to boost traffic; there are also casinos using them to simulate real players, making the games appear more 'real,' but actually to suppress you and lead you to lose money."

"There are also some Web2 players who batch farm mobile games, leveling up accounts and then selling these upgraded accounts," he added. However, Wilton indicated that the core business of this farm is actually "manufacturing."

The operator would buy damaged or obsolete smartphones at low prices, then modify them through software and other means, ultimately packaging them as "self-service phone farm" devices for export to overseas markets. The project can produce over 1,000 deployable farm phones each week, with each "phone farm kit" containing about 20 devices. Wilton stated that these people do not operate the phones themselves. They do not go out to farm airdrops or perform related operations. Their main business is actually packaging and selling these devices to those who want to operate from home. All you need to do next is keep these devices online and buy more phones to connect.

Wilton lamented that it's no wonder "robot-assisted crypto airdrop farming" has become a significant issue in the crypto industry. The so-called crypto airdrop farming refers to obtaining free tokens that are supposed to be rewarded to real early users by creating a large number of wallet addresses and faking user behavior. Although most crypto airdrops do not require phone number verification, the unique device fingerprints and IP addresses can still bypass Sybil protection mechanisms.

Such "farming airdrops" often lead to farm users immediately selling their tokens after receiving them, impacting market prices, while also making it harder for genuine users to obtain airdrops. Many projects experience a surge of fake activity before airdrops, and once the airdrops are distributed, user numbers and token prices often plummet rapidly.

Frequent Controversies Surrounding Crypto Airdrops, Robot Behavior Widely Criticized

Whether through controlling large numbers of phones or using a single computer, robot behavior has caused significant damage to crypto airdrop activities. Last June, the Ethereum zero-knowledge (ZK) Layer2 scaling project ZKsync faced heavy criticism due to airdrop-related bot attacks, with users accusing it of opening the floodgates for "bot farming."

On-chain data analysis platform Lookonchain reported that an "airdrop hunter" claimed over 3 million ZKsync (ZK) tokens through 85 wallet addresses, with a total value of up to $753,000 at the time. Another user publicly boasted on social media that they profited nearly $800,000 through an "extremely efficient $ZK Sybil attack strategy."

A "Sybil attack" is a security threat behavior where an attacker creates multiple false identities to gain an unfair advantage in a network system. The term originates from a book titled "Sybil," which describes a case of a woman with dissociative identity disorder. Mudit Gupta, the security chief of ZKsync's competitor Polygon, referred to it as "possibly the easiest airdrop to farm and the most farmed airdrop in history," attributing the problem to the lack of anti-bot mechanisms. Although ZKsync set seven qualification criteria this time to prevent Sybil attacks.

ZKsync responded in its official FAQ that current Sybil attack strategies have become increasingly complex, making it difficult to distinguish them from real users; and if overly strict screening criteria are adopted, while it may block some Sybil attackers, it could also mistakenly harm many genuine users.

However, just last month, Binance offered a different perspective while addressing bot behavior in its "Binance Alpha Points" program. "Traditional bots usually follow predictable, repetitive behavior patterns, making them relatively easy to identify," a Binance spokesperson said in an interview. "But with the rise of AI-driven bots, we are now facing a system that closely mimics human behavior—from browsing habits to interaction times—making identification significantly more challenging." Binance stated that the platform is continuously increasing its anti-bot efforts and developing new tools to identify abnormal operations from large-scale behavior patterns. For example, address entity association analysis can help identify clusters of wallets controlled by the same entity, even if these wallets appear independent on the surface.

These analyses are particularly crucial for revealing behaviors such as disguised holdings, multisend manipulation, and wash trading—methods commonly used by AI-driven bots to fabricate real engagement and false liquidity. And the impact is not limited to crypto airdrops; bots have also been accused of flooding the market with countless worthless meme coins. Coinbase's product head Conor Grogan recently pointed out on X platform that "most tokens launched on PumpFun and LetsBonk platforms are almost entirely controlled by bots." He found that on the meme coin platform LetsBonk, top accounts release a new token on average every three minutes.

Daren Matsuoka, a data scientist and partner at a16z Crypto, believes that Sybil attacks are a problem that has only emerged in recent years. "Throughout most of the development history of cryptocurrencies, we inherently had a certain level of Sybil resistance—because gas fees on these Layer1 blockchains have always been high." He stated in an a16z Crypto podcast in April this year.

"In the past, you needed to pay a few dollars or even tens of dollars in transaction costs to qualify for airdrops. But with the continuous optimization of infrastructure, the cost of operations has now become very low. I believe this will fundamentally change the dynamics of the attack and defense mechanisms." a16z Crypto's CTO Eddy Lazzarin has been emphasizing the importance of building a "proof of human" mechanism.

"AI can now generate a large number of realistic behavior records. The most advanced bot farms are now almost impossible to reliably identify, and it won't be long before those with moderate technology become equally undetectable." Lazzarin wrote in an article in May this year. What interests Lazzarin most is the construction of a "proof of personhood" mechanism: it should allow real humans to easily and freely verify their identity, while making it costly and difficult for bots or fraudsters to commit large-scale forgery. He mentioned that the iris scanning project World initiated by Sam Altman is a typical example of such a mechanism. The core idea of the project is that each person can only register for one World ID, with its uniqueness verified through iris scanning (since everyone's iris is unique).

Lazzarin added in a podcast on airdrop topics: "I really hope to see more people try systems like World ID, which combines biometric technology with privacy protection mechanisms to limit each person to only one identity ID."

However, Ethereum co-founder Vitalik Buterin believes that "one person, one ID" is not a perfect solution, as it means that all historical behaviors could be tied to a single attack point—namely, the key corresponding to that identity. If leaked, the risks are significant. At the same time, he pointed out that biometric and government identity information could also be forged.

Why Not Simply Cancel Crypto Airdrops?

If crypto airdrops are so easily manipulated, the most straightforward choice seems to be to simply cancel the airdrop mechanism. However, there are also viewpoints that believe airdrops still have their significance. Distributing tokens to real participants in the protocol not only helps achieve decentralization of project governance but can also disperse control through mechanisms like granting voting rights. Additionally, airdrops often generate a lot of buzz. "An obvious reason is: when you distribute a large number of potentially valuable tokens, it attracts a lot of attention, which in itself has a marketing effect," Lazzarin stated. "Airdrops are essentially a marketing tool."

Wilton also agreed and pointed out that project teams should anticipate that some users will sell their tokens, which is essentially the marketing cost of acquiring users, with the key being to ensure that these users are real people and "willing to stay long-term." Meanwhile, Binance believes that automated bots are not entirely harmful. In fact, in certain scenarios, if used properly and transparently, bots can play a positive role—such as providing liquidity, executing strategies on behalf of users, or conducting stress test simulations during audits.