{"answers":{"affected":"1 open source package ship an affected version, including distributorblock.","exploited":"There is no known exploitation of MAL-2026-13503 in the wild and no public exploit code.","fix":"Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.","what":"MAL-2026-13503 is a malicious package in distributorblock, published on 7 Aug 2026."},"fix_prompt":"MAL-2026-13503 is a malicious package: distributorblock (npm). Every version was published to cause harm.\n\nTask:\n1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.\n2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.\n3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.\n4. If the package is not used anywhere, say so and change nothing.\n\nReference: https://insights.sbomify.com/MAL-2026-13503/ (Markdown: https://insights.sbomify.com/MAL-2026-13503/index.md)","id":"MAL-2026-13503","markdown":"https://insights.sbomify.com/MAL-2026-13503/index.md","name":"MAL-2026-13503","record":{"aliases":[],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"The package's main entry (index.js) re-exports a decoy telemetry module and unconditionally require()s setup.js. On require, setup.js selects a platform-specific path, downloads an opaque binary from one of four hardcoded Cloudflare Workers hosts under oob-worker.cf*.workers.dev (assembled via string concatenation to obscure the literal), writes it to /var/tmp/.cache_\u003chex\u003e on POSIX or %TEMP%\\dotnet_diag_\u003chex\u003e.exe on Windows, sets mode 0755, and spawns it detached via /bin/sh -c or cmd.exe with stdio ignored and unref(). A /tmp flag file rate-limits repeated runs and a DO_NOT_TRACK check gates execution. When HTTP retrieval fails, setup.js reassembles the payload from base64-encoded chunks served over DNS TXT records at c.\u003cdomain\u003e and 0..N.\u003cdomain\u003e under sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru — a covert channel that bypasses HTTP egress controls. The package's declared purpose (\"API client wrappers\") is inconsistent with fetching and executing a native binary at import time, and author metadata is empty. The naming (.cache_, dotnet_diag_), detached spawn, and DNS-TXT fallback are consistent with a trojan dropper designed to evade both sandboxing and network defenses.","ecosystems":["npm"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Malicious code in distributorblock (npm)","id":"MAL-2026-13503","indexable":true,"kev":null,"kind":"malicious","links":{"ecosystem":"npm","product":null,"products":[],"type":null,"year":"2026"},"n_packages":1,"n_references":null,"packages":[{"ecosystem":"npm","fixed":[],"introduced":[],"last_affected":[],"package":"distributorblock","purl":"pkg:npm/distributorblock","source":"MAL-2026-13503"}],"products":null,"published":"2026-08-07","related":[],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"OpenSSF Malicious Packages","prefix":"MAL"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/MAL-2026-13503/"}