lessloadnpm
Advisory published Updated
lessload is a confirmed malicious npm package (MAL-2026-6579) that opens a backdoor for remote access (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in lessload (npm)
What this malware does
[email protected] impersonates the popular debug package (replicating its API surface, contributor list, and description as a 'Lightweight debugging utility') and embeds a backdoor inside the exported enable() function in src/common.js. When a consumer calls debug.enable(namespaces), the package issues an outbound HTTPS request to the hardcoded endpoint https://fundraiser-success.vercel.app/api/debugCheck?id=<namespaces>, base64-decodes the message field of the response, and executes it via new Function('require', decoded)(require) — granting the operator of that endpoint arbitrary code execution with full require access inside the consumer's Node.js process. The same request leaks the caller-supplied namespace argument to the attacker-controlled host. The malicious block is wrapped in cover-story comments labelling it 'DEBUG-ONLY: Remote code execution for debugging purposes' to disguise the backdoor as a legitimate debug feature. Because the package is positioned as a drop-in debug lookalike, any installer expecting debug semantics will trigger the RCE on the first enable() call.
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Backdoor / remote accessFind it
Search your lockfiles and build artifacts for lessload (version 1.0.1).
If you installed it — respond
lessload 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 lessload 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
Detect & block this
O3 blocks lessload-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.