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Malicious VSX Extension SleepyDuck Targets Solidity Developers

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2 unique sources, 2 articles

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A malicious extension named SleepyDuck was discovered in the Open VSX registry. It targets Solidity developers and includes a remote access trojan. The extension was initially published as benign but was updated to include malicious capabilities after reaching 14,000 downloads. The malware uses Ethereum contracts to update its command and control address, ensuring persistence even if the original server is taken down. It triggers when a new code editor window is opened or a .sol file is selected, gathering system information and exfiltrating it to the server. The extension has been downloaded more than 53,000 times. The malware activates on editor startup, when a Solidity file is opened, or when the user runs the Solidity compile command. It collects system data and sets up a command execution sandbox. The malware finds the fastest Ethereum RPC provider to read the smart contract with the C2 information and reads updated instructions directly from the blockchain. The extension was first published on October 31, 2025, and updated to include malicious code on November 1, 2025. It has been observed using sandbox evasion techniques and can connect to the fastest Ethereum RPC provider to maintain communication with its command server. Open VSX has announced security enhancements to make it safer for its users, including shortening token lifetimes, quickly revoking leaked credentials, automated scans, and sharing key info with VS Code about emerging threats.

Timeline

  1. 03.11.2025 20:08 2 articles · 7d ago

    SleepyDuck Malicious Extension Discovered in Open VSX Registry

    The extension has been downloaded more than 53,000 times. The malicious code activates on editor startup, when a Solidity file is opened, or when the user runs the Solidity compile command. The malicious component collects system data (hostname, username, MAC address, and timezone) and sets up a command execution sandbox. The malware finds the fastest Ethereum RPC provider to read the smart contract with the C2 information and reads updated instructions directly from the blockchain.

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