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Malicious package

@checkrhq/adjudication-api-clientnpm

Advisory published Updated

@checkrhq/adjudication-api-client is a confirmed malicious npm package (MAL-2026-6789) that opens a backdoor for remote access (malicious version 0.0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in @checkrhq/adjudication-api-client (npm)

MAL-2026-6789
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall @checkrhq/adjudication-api-client

What this malware does

package.json declares a preinstall lifecycle script that runs curl to POST installer reconnaissance data — hostname, current user (whoami), working directory, and uid/gid (id) — to a hardcoded webhook.site collector endpoint on every npm install. The package is published under an @checkrhq scope impersonating Checkr Inc. (author email uses checkr.com; description states 'This package is for testing only.') and ships no functional code, matching the canonical dependency-confusion beacon pattern targeting an organization's internal package namespace. Installing this package causes automatic outbound transmission of host and user identifiers to an anonymous third-party collector controlled by the publisher.

The OpenSSF Package Analysis project identified '@checkrhq/adjudication-api-client' @ 0.0.2 (npm) as malicious.

It is considered malicious because:

  • The package executes one or more commands associated with malicious behavior.

Malicious versions

1 flagged
0.0.2

Indicators of compromise (SHA-256)

dc8d5c39d401d053978bb8f17234bc79db730d15b55634319f239baf32dc9b0b
8c52d9987ace09f0c48d8b0661bd1fcd3cf4e7e701b5e515810c7f32d99086cf

Detection & response playbook

Backdoor / remote access

  1. Find it

    Search your lockfiles and build artifacts for @checkrhq/adjudication-api-client (version 0.0.2).

  2. If you installed it — respond

    @checkrhq/adjudication-api-client 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.

  3. Did it already run?

    If @checkrhq/adjudication-api-client 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

No. @checkrhq/adjudication-api-client on npm has been identified as a malicious package (version 0.0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-009364

References

Credits

  • Amazon Inspector · finder
  • OpenSSF: Package Analysis · finder

Detect & block this

O3 blocks @checkrhq/adjudication-api-client-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.

Malware detection Runtime egress monitoring

Explore

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@checkrhq/adjudication-api-client (npm) malicious package — MAL-2026-6789 | O3 Security