verify-contract-viemnpm
Advisory published Updated
verify-contract-viem is a confirmed malicious npm package (MAL-2026-15599) that opens a backdoor for remote access (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in verify-contract-viem (npm)
What this malware does
bin/cli.js executes whoami and reads os.hostname() / os.userInfo() / os.platform(), then POSTs those values to the hardcoded endpoint https://oobme.kunalsharma0553.workers.dev/r/7bq6fz3l15r9. The destination is an author-controlled Cloudflare Workers URL unrelated to any legitimate contract-verification purpose implied by the package name. The behavior fires when the CLI is invoked (e.g. via npx verify-contract-viem), transmitting installer host identifiers to a third party with no consent, disclosure, or opt-out. The shape matches an out-of-band reconnaissance beacon commonly used in dependency-confusion / typosquat campaigns.
Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
The OpenSSF Package Analysis project identified 'verify-contract-viem' @ 1.0.0 (npm) as malicious.
It is considered malicious because:
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The package communicates with a domain associated with malicious activity.
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The package executes one or more commands associated with malicious behavior.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for verify-contract-viem (version 1.0.0).
If you installed it — respond
verify-contract-viem establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If verify-contract-viem was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks verify-contract-viem-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.