{"id":"MAL-2026-12554","summary":"Malicious code in checkout-desktop-bnpl (npm)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (dd165a0865ff5e6b4a488e6a81018740deff0071604e6d06fff046d2c8a1b0a1)\nThe package presents itself as a checkout/BNPL library but exports an empty CheckoutDesktopBnpl class with no BNPL functionality. On require() of the main module, index.js loads _polyfill.js, which selects a platform-specific remote endpoint, downloads a binary payload, writes it to /tmp or %TEMP% under decoy names such as dotnet_diag_\u003chex\u003e.exe or.cache_\u003chex\u003e, chmods it 0755 on Unix, and spawns it detached via /bin/sh -c or cmd. Destination hostnames are obfuscated via array-join string splitting and resolve to Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev) with a DNS-over-TXT fallback channel that queries c.\u003cdomain\u003e and N.\u003cdomain\u003e TXT records at sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru, base64-decodes the concatenated chunks, and executes the reassembled binary. There is no hash or signature verification, and the delivery hosts are unpinned and attacker-controlled. Any process that imports this package triggers arbitrary remote code execution on the installer's machine.\n","modified":"2026-08-05T14:35:21.520944468Z","published":"2026-08-05T14:13:44Z","database_specific":{"malicious-packages-origins":[{"import_time":"2026-08-05T14:20:13.734219435Z","modified_time":"2026-08-05T14:13:44Z","sha256":"dd165a0865ff5e6b4a488e6a81018740deff0071604e6d06fff046d2c8a1b0a1","source":"amazon-inspector","versions":["35.5.1"],"id":"IN-MAL-2026-015217"}]},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/checkout-desktop-bnpl/v/35.5.1"}],"affected":[{"package":{"name":"checkout-desktop-bnpl","ecosystem":"npm","purl":"pkg:npm/checkout-desktop-bnpl"},"versions":["35.5.1"],"database_specific":{"cwes":[{"cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code"}],"indicators":{"evidence_files":[{"sha256":"148356ac826fd7e1d8e9b827f3f667be1c7c004de2663af1aad2872560869894","tlsh":"48a1b79a12a6b0198f7097e4c6178826f65ff5633780c2d4fb5ca9885fb25248372dfc","path":"_polyfill.js"},{"path":"index.js","sha256":"81b19599b68928c36832581d08bf49b3fcfb6710b0d4357bbd481e401dfac892","tlsh":"d6f0fc8b53dea56397b0a2e6de634045fb12cc258b87119876d450ef0ab081442ddeb6"}],"package_integrity":[{"filename":"checkout-desktop-bnpl-35.5.1.tgz","hashes":{"sha1":"cbb8f992a5c57a5ebff975fe7efb999de7a6e9e9","sha512_sri":"sha512-GStOVMrptv1dvc0G/P2/rJX+a4Dr/tiih42AjKPlHCSRTU8RAtkMFeNfs6CYojgdlqQZydW2KWthGbJ2Gi0SoQ=="}}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/checkout-desktop-bnpl/MAL-2026-12554.json"}}],"schema_version":"1.8.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}