Taking a Closer Look at Alex Lab Exploit

3 min read

Learn how Alex Lab was exploited, resulting in a loss of assets worth $4.3 million.


On May 14, 2024, the XLink bridge of Alex Lab was exploited on the BNB chain, which resulted in a loss of assets worth approximately $4.3 million.

Introduction to Alex Lab#

Alex is the one-stop DeFi services platform on Bitcoin via Stacks.

Vulnerability Assessment#

The root cause of the exploit is a compromise of the private keys of the deployer wallet.


Step 1:

We attempt to analyze one of the attack transactions executed by the exploiter.

Step 2:

Following the compromise of the private key due to a rumored phishing attack, the exploiter initiated five different upgrades of the Bridge Endpoint contract to its malicious implementation. These upgrades caused the affected contract to change to its unverified bytecode form.

Step 3:

After this, two addresses initiated token withdrawals from the affected contracts, as viewed in this and the other transactions. The stolen funds include assets in BTC, USDC, and Sugar Kingdom Odyssey (SKO).

Step 4:

A total of $4.3 million worth of assets were then transferred to this address and the other address, likely controlled by the attacker.

Step 5:

The team was able to secure approximately $5 million worth of assets on the Ethereum Mainnet.

Step 6:

The initial attacker, likely this address, reportedly failed to put sufficient access control on the malicious contract implementation. Consequently, a white-hat rescue was attempted by paying roughly 1.5 BNB in transaction fees to front-run the transaction of the original attacker.


In addressing the vulnerability exposed by the Alex Lab exploit, it's crucial to emphasize the paramount importance of safeguarding private keys, which, when compromised, can lead to devastating consequences for DeFi protocols. A robust strategy for protecting these keys involves the utilization of secure storage solutions, such as hardware wallets for cold storage, which keep the majority of assets offline and thus less susceptible to online attacks. For operational liquidity, a minimal amount of assets can be stored in hot wallets, though with stringent security measures in place.

Implementing multi-signature wallets adds an additional layer of security, requiring multiple parties to authorize transactions, which significantly mitigates the risk of unauthorized access through compromised keys. Regular security audits and vulnerability assessments are essential to identify potential security loopholes and ensure that the protocols for managing and accessing private keys are updated and secure.

Continuous education and vigilance are necessary in light of the threat that phishing, social engineering, and malware like Trojan viruses pose. Regular security training for team members on the latest threats and secure communication practices can greatly reduce the risk of such attacks. Keeping software, including wallets and security tools, up-to-date is also critical for protecting against known vulnerabilities.

Even with robust security protocols in place, the risk of vulnerabilities being exploited remains. In such cases, the role of Neptune Mutual becomes invaluable. By establishing a dedicated cover pool with Neptune Mutual, the negative impacts of incidents similar to the Alex Lab exploit can be greatly reduced. Specializing in providing coverage for losses stemming from smart contract vulnerabilities, Neptune Mutual employs parametric policies tailored to these unique risks. While losses due to private key compromises typically fall outside our coverage scope, exceptions may be considered under extraordinary circumstances.

Working with Neptune Mutual streamlines the recovery process for users by lessening the need for extensive proof of loss documentation. After an incident is verified and resolved through our comprehensive incident resolution protocol, our priority shifts to quickly providing compensation and financial support to those affected. This method ensures swift assistance for users impacted by such security breaches.

Our coverage spans several key blockchain platforms, including EthereumArbitrum, and the BNB chain, offering extensive support to a variety of DeFi users. This broad coverage bolsters our capacity to protect against a range of vulnerabilities, thereby enhancing the overall security of our diverse client base.

Reference Source ChainAegis