toll_freenpm
Advisory published Updated
toll_free is a confirmed malicious npm package (MAL-2026-11159) that opens a backdoor for remote access (malicious versions 1.0.1, 1.0.2). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in toll_free (npm)
What this malware does
package.json declares both preinstall and postinstall lifecycle hooks that run curl against a hardcoded webhook.site endpoint, sending the installer's username ($(whoami)), hostname ($(hostname)), current working directory ($PWD), and timestamp as query parameters. This fires automatically on npm install, before any code the installer intended to run. webhook.site is a third-party HTTP inspection service used to collect arbitrary request data; the specific endpoint ID is controlled by whoever created it. There is no legitimate functionality shipped with the package that would explain this beacon.
The OpenSSF Package Analysis project identified 'toll_free' @ 1.0.1 (npm) as malicious.
It is considered malicious because:
- 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 toll_free (2 malicious versions).
If you installed it — respond
toll_free 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 toll_free 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 toll_free-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.