Stablecoins such as USDC and USDT are among the most widely used assets in the crypto industry. Traders, liquidity providers, and everyday users rely on them because they maintain value stability and move fast across platforms. The popularity also puts them in a position where they are prime targets for attacks. One of the easiest methods used by hackers includes taking advantage of a core feature of the ERC-based token system referred to as infinite approval.
Infinite approval gives a decentralized application permission to access and move a user's tokens without asking for repeated confirmations. While this feature exists to make transactions smoother, it has also opened the door to a wide range of wallet-draining attacks. When abused, it allows hackers to quietly withdraw stablecoins from a user's wallet without requiring further permission.
This article will explain how infinite approval works, how attackers use it against USDC and USDT holders, why stablecoins are especially attractive targets, and what users can do to stay safe.
Understanding Infinite Approval in ERC-Based Tokens
For any decentralized application to move any user's tokens, permission is required. Permission, in this case, is referred to as an approval. Normally, a user would be able to choose to approve only the exact amount they want to use. However, most platforms encourage users to select much broader options: infinite approval.
Why Infinite Approval Exists
Infinite approval was created for convenience. It helps users by:
Reducing repeated pop-ups
Gas-fee saving
Allowing smooth interaction with DeFi platforms
Making every swap or liquidity action not require approval confirmation
Simplified: Once a user gives infinite approval, the platform can move tokens at any time without asking again.
The Hidden Risk
If such permission is granted for a malicious platform or a compromised smart contract, an attacker will be able to move tokens at any time, and the user does not get any warnings during the withdrawal.
This is why infinite approval has become one of the most dangerous, misunderstood security issues within Web3.
Why Attackers Focus on Stablecoins (USDC & USDT)
Stablecoins are the number one assets targeted in infinite approval scams. The reasons are simple and very practical.
Stablecoins Hold Predictable Value
Stablecoins represent dollar-like value in crypto. Here's why hackers prefer them:
There is no price volatility
They can be used instantly
They are easy to launder or convert
Almost every wallet holds stablecoins
Most crypto users keep a balance of USDT or USDC on hand for:
Trading pairs
Farming
Lending
Fees
Market movements
That makes stablecoin approvals extremely common.
Approvals are often old and forgotten
Users interact with many platforms over time. They may have approved:
Old staking sites
Trial platforms
Forked versions of well-known dApps
Project testing
Dead websites
These permissions may be valid for an indefinite period. The attackers search for such forgotten approvals and misuse them.
Stablecoins Move Quickly Across Chains
When hackers steal stablecoins, they can quickly:
Bridge them
Change places
Mix them
Hide them in smart contract routes
This speed makes recovery extremely difficult.
How Infinite Approvals Attack Works: A Smooth Breakdown
Here is a simple, natural-flow explanation of how these attacks happen.
Step One: The User Visits a Fake or Compromised Platform
This might be:
A fake staking platform
A token swap scam page
A cloned website, looking similar to any famous dApp.
Airdrop fake website
A website shared by a scammer pretending to support
The website is asking for a token approval "to enable trading," "to access liquidity," or "to claim rewards."
Step Two: The User Signs an Approval Transaction
It looks normal.
Nothing suspicious appears.
The wallet displays a standard approval request.
But the approval is granted to a malicious contract, which the hacker controls.
Step Three: Infinite Access is Provided
The wallet of the user has now allowed the malicious contract to move unlimited amounts of USDC or USDT.
Step Four: The Attacker Moves the Tokens
The attacker calls the permission, not through the user's wallet but through their own; that is how they will be able to:
Move stablecoins from the victim's wallet
Send them to a wallet of their own
Multiple transfers with no user confirmation
The victim receives no warning.
The signature is not required from the wallet.
The blockchain considers this a valid action since the user gave permission for it.
Step Five: The stolen stablecoins are laundered
Attackers immediately transfer the funds across:
Multi-chain bridges
Mixers
Decentralized Exchanges
Routing contracts
In a matter of moments, the money is virtually irretrievable.
Comparison: Infinite Approval Risks for USDC vs USDT
Category | USDC | USDT |
Issuer Control | Can freeze under certain conditions | Rarely used |
Popularity | Extremely high | Even higher |
Usage in scams | Very common | Most common |
Approval habits | Often used in DeFi | Used everywhere including CEX-related tools |
Likelihood of forgotten approvals | High | Very high |
How Hackers Trick Users Into Granting Infinite Approval
Attackers use multiple strategies to deceive users. Here are the most common and harmful ones.
Fake Decentralized Application Websites
Hackers copy a well-known website and host a fake version. It looks identical to:
Uniswap
Curve
PancakeSwap
Sushi
Aave
Only one thing is different — the approval goes to the hacker’s contract.
Compromised Legitimate Websites
Sometimes the platform itself is hacked. Attackers may change:
DNS settings
Front-end scripts
Gateway links
Smart contract references
Users who trust the real website unknowingly approve malicious permissions.
Support and Admin Impersonation
Hackers pretend to be:
Project admins
Telegram moderators
Customer support
Brand ambassadors
They ask users to verify their wallets or “fix an error” by approving a new contract.
Airdrop Phishing
Attackers send random tokens to a user’s wallet. When the user tries to check, swap, or explore them, a website forces them to approve an unlimited permission.
Common scam airdrops include:
Reward tokens
Fake governance tokens
Duplicate versions of stablecoins
Exploiting Upgradeable Contracts
Some platforms use upgradeable smart contracts.
If attackers gain access to the administrative keys, they can:
Replace the contract
Redirect existing approvals
Drain connected wallets
This has happened multiple times in the DeFi world.
How to Protect Your Wallet From Infinite Approval Exploits
Use Limited Approvals
Many wallets now allow users to approve a specific amount instead of granting unlimited access.
Revoke Old Approvals Regularly
Clear out approvals from platforms you no longer use. Forgotten permissions are the most common attack path.
Bookmark Official Websites
Never rely on search engines or ads. Use saved, verified bookmarks.
Use Wallet Security Extensions
Tools that warn users before approval signatures can help identify risky actions.
Avoid Interacting With Unknown Airdropped Tokens
Treat all unrequested tokens as potential scams.
Read Approval Prompts Carefully
If the approval does not match the action you're trying to perform, stop immediately.
Conclusion
Infinite approval is one of the core features that keeps decentralized finance smooth and fast. But when misused, it becomes a powerful attack vector that allows hackers to drain stablecoins like USDC and USDT from unsuspecting users.
By understanding how infinite approval works, how attackers exploit it, and why stablecoins are prime targets, users can significantly reduce the risk of wallet drains. The key lies in practicing mindful signing habits, managing wallet permissions, and staying alert to phishing methods.
Education and awareness remain the strongest defenses in the evolving world of crypto security.
FAQs: People Also Ask
Q1. What happens if I accidentally give infinite approval to a malicious contract?
The attacker can move your tokens without further permission. Revoking the approval immediately helps prevent further loss.
Q2. Can I check which platforms already have approval for my USDT or USDC?
Yes. Tools such as Revoke.cash, Debank, Zerion, and Exploit trackers show active approvals.
Q3. Do hardware wallets protect against infinite approval attacks?
Hardware wallets protect your private key, but they cannot prevent you from granting harmful approvals if you choose to approve them.
Q4. Why do wallets not block malicious approvals automatically?
Approvals themselves are not harmful. The malicious intent is invisible until the connected contract abuses the permission.
Q5. Can stolen USDT or USDC be frozen?
USDC can be frozen under certain conditions, such as when large amounts are involved and formal requests are made. USDT freezes are less common.
Q6. Why are stablecoins stolen more often than regular tokens?
Because they have predictable value, move quickly, and remain in high demand among hackers.
Q7. Is infinite approval always unsafe?
Infinite approval is safe when granted to trustworthy, established platforms. The danger arises when approvals are granted to unknown, cloned, or compromised contracts.
