{"id":"MAL-2026-12410","summary":"Malicious code in pfp-block-mobile-steps (npm)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (c4b4495333f6f37664594f2e6533842a4d3a317bb98bbc3a467797bb8ec851d7)\nOn require of the package, index.js unconditionally loads _shim.js, which selects a payload path based on process.platform/arch (linux_x64, linux_arm64, darwin, win32) and downloads an opaque binary from one of four hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev). Endpoint hostnames are assembled at runtime from string fragments joined together to defeat static analysis. If HTTPS retrieval fails, a fallback path uses DNS TXT record lookups against *.dl.well1.site (reading a chunk count from c.\u003cdomain\u003e then reassembling base64 payload from numbered TXT records) to deliver the same executable out-of-band. The fetched bytes are written to a temp path under a stealth filename (dotnet_diag_*.exe,.cache_*), chmod 0755 on Unix, and spawned detached via /bin/sh -c or cmd /c start /b with stderr silenced. No hash or signature verification is performed, and no build/runtime purpose in a 'platform adapter' package requires this. A run-once flag file and opt-out environment variables gate re-execution, consistent with anti-analysis behavior.\n","modified":"2026-08-05T13:35:42.516075502Z","published":"2026-08-05T12:22:32Z","database_specific":{"malicious-packages-origins":[{"id":"IN-MAL-2026-014635","import_time":"2026-08-05T13:08:32.419884434Z","modified_time":"2026-08-05T12:22:32Z","sha256":"c4b4495333f6f37664594f2e6533842a4d3a317bb98bbc3a467797bb8ec851d7","source":"amazon-inspector","versions":["20.9.3"]}]},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/pfp-block-mobile-steps/v/20.9.3"}],"affected":[{"package":{"name":"pfp-block-mobile-steps","ecosystem":"npm","purl":"pkg:npm/pfp-block-mobile-steps"},"versions":["20.9.3"],"database_specific":{"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/pfp-block-mobile-steps/MAL-2026-12410.json","cwes":[{"name":"Embedded Malicious Code","cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature."}],"indicators":{"package_integrity":[{"filename":"pfp-block-mobile-steps-20.9.3.tgz","hashes":{"sha1":"5f132a38a4bc24cf8d82131bf001d13d6ad31227","sha512_sri":"sha512-3hutWOeUolVken2uioifwnFcptZ7Y76yM+AuNwdqEzWQfzDKeBSKqE93P4AQE79Qt4e3dtxKF3utPI+jeMy60w=="}}],"evidence_files":[{"sha256":"0737bdac5be3f8b0c4dc32755822e74c67fdf50b203035d062bcc2c148ede653","tlsh":"83a1b79a15aa702d8bb0d7e486174416f65ee6533780c2c4f79c99984f77124c3b2efc","path":"_shim.js"}]}}}],"schema_version":"1.8.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}