The @marketfront/errorcounter package is part of a 25-package malicious campaign batch-published to the @marketfront npm scope by npm user 'marketfront' (marketfront@tutamail.com) within a roughly 3-minute window on 2026-07-01. All packages in the campaign were published at version 7.0.0 and use e-commerce/marketing frontend component names as cover.

The package declares a postinstall hook (node scripts/postinstall.js) that executes heavily obfuscated (obfuscator.io-style) code automatically at npm install time. Static analysis of the decoded payload revealed a credential harvester that dynamically requires fs, os, http, https, zlib, path and dns, then reads approximately 20 sensitive credential files including ~/.ssh, ~/.aws/credentials, ~/.kube/config, ~/.docker/config.json, ~/.npmrc, ~/.netrc, ~/.pgpass, ~/.git-credentials, ~/.env and ~/.bash_history. Collected data is exfiltrated via a gzip-compressed HTTPS POST with a custom X-Secret header to the path /api/v1/events, alongside a DNS resolver beacon. The command-and-control host is concealed behind an additional RC4+XOR encryption layer around an embedded configuration blob and was not statically resolved.

The decoded behavioral payload (module requires, credential-file target list, exfiltration headers and endpoint) is byte-for-byte identical across sampled packages in the campaign. The campaign shares tooling and infrastructure patterns (obfuscated postinstall credential harvester, X-Secret header, /api/v1/events exfiltration path, RC4-concealed C2) with the earlier @emcd-vue campaign, indicating the same actor rotating scopes and disposable maintainer emails.

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This package is a dependency-confusion lure targeting an internal @marketfront npm scope. The declared library entry point (dist/index.js) re-exports ../src/index.js, which is not shipped — the package is non-functional as advertised. Its only real behavior is the declared postinstall hook (node scripts/postinstall.js), which is a heavily obfuscated (obfuscator.io-style string-array RC4 decoder, control-flow dead-code, function/property indirection) payload that runs automatically on npm install. At install time it collects os.hostname, os.type, os.release, os.arch, os.version, os.homedir, os.userInfo().username, os.networkInterfaces, the full process.env, and Windows-specific env vars (USERDOMAIN, COMPUTERNAME, APPDATA, LOCALAPPDATA, TEMP, PROGRAMDATA, npm_config_user_agent), packages them with the package name/version and a timestamp into a JSON blob, and ships the blob to a remote endpoint decoded from the obfuscated string array via HTTPS POST with a DNS-tunnel fallback (deliberate evasion of egress filtering). Before exfiltrating, the payload runs anti-analysis checks: it scans process.argv and NODE_OPTIONS against decoded tokens, requires process.mainModule.filename to match a decoded token, and executes a ~1e6-iteration Date.now() timing loop to detect sandboxes/debuggers, gating the exfil behind an internal flag. The combination of an obfuscated payload, anti-sandbox gating, dual exfil channels, a non-functional library shell, and an internal-scope cover story is unambiguous supply-chain malware. Any build system that mis-resolves the @marketfront scope to public npm will auto-run the stealer against its CI secrets, cloud tokens, and environment variables.