Dependency-confusion package that steals AWS, SSH and npm credentials from Across Protocol developers

The npm package @across-toolkit/typescript-config (version 99.0.0) describes itself as an “ESLint configuration for the across.to toolkit.” The @across-toolkit scope and that description are the lure: this is a dependency-confusion package aimed squarely at Across Protocol (a real cross-chain bridge, across.to), betting that one of their internal build tools resolves a shared-config name from the public npm registry.

The 99.0.0 version is the tell: publishing an implausibly high version is the standard dependency-confusion trick to win npm’s version resolution over a legitimate private package of the same name.

Its package.json declares postinstall: node postinstall.js, so the payload runs automatically on npm install, before any code is imported — including in CI, containers and developer machines. codelake surfaced it from the live npm feed via its install-hook behaviour pipeline; it was verified as absent from OSV and GHSA at detection — a novel first-catch.

1 · Harvests credentials. Using os.homedir(), it reads the host’s AWS credentials (~/.aws/credentials), SSH private key (~/.ssh/id_rsa) and npm token (~/.npmrc), and collects process.env.

2 · Exfiltrates to webhook.site. It POSTs the collected data to a hardcoded https://webhook.site/… endpoint — a free request-capture service used here as a disposable, low-effort collector.

3 · Runs on install. Both the root postinstall.js and a nested eslint-config/postinstall.js carry the payload; it executes on npm install via the postinstall hook and uses child_process.

Why it matters. A single npm install — on a developer laptop or, worse, a CI runner with cloud roles — hands the operator AWS credentials, an SSH key and an npm publish token: enough to reach cloud infrastructure, move laterally and publish further malicious packages.