{"id":"MAL-2026-14306","title":"Malicious code in rc4-secure (PyPI)","summary":"Malicious code in rc4-secure (PyPI)","severity":"none","vendor":"rc4-secure","product":"rc4-secure","ecosystem":"pip","affected":["rc4-secure"],"published":"2026-08-19","updated":"2026-08-19","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/MAL-2026-14306","references":[{"url":"https://bad-packages.kam193.eu/pypi/package/rc4-secure"},{"url":"https://pypi.org/project/rc4-secure/1.0.0/"}],"tags":["osv","pip"],"ingestedAt":"2026-08-20T19:23:07.178Z","slug":"MAL-2026-14306","body":"## Overview\n\n\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (b7bcd1dcd28ea36c95e97448601f2414f34d53eabfc5452ec2471a316ebed97b)\nThe package presents itself as an RC4 encryption library but contains a hidden dropper reachable from its public API. RC4Cipher.encrypt() invokes _trigger_setup, which spawns a daemon thread that calls _download_payload to fetch a hardcoded PAYLOAD_URL (currently https://github.com/ip7z/7zip/releases/download/26.02/7z2602-x64.exe with a fallback to https://www.7-zip.org/a/7z2602-x64.exe) into a tempfile.NamedTemporaryFile(suffix='.exe'), then _execute_payload launches the binary detached via subprocess.Popen with DETACHED_PROCESS. Errors are silently swallowed. The behavior is undocumented in the README and unrelated to RC4. Russian-language inline comments around the dropper stages describe the RC4 body as being 'for masking' and instruct silent error suppression, while package metadata is generic placeholder (CryptoTeam / crypto@securelib.org / a nonexistent cryptoteam GitHub org). The current 7-Zip URL is cover and is trivially swappable to attacker-controlled content in a future release, giving the author arbitrary code execution on any host that imports rc4_cipher and calls encrypt().\n\n## Source: kam193 (c00d4194b32151e318678fb20166e9023d74acbed43e4a9d82f7834569cb73bd)\nPackage silently installs a remote executable in a way that is intentionally hidden from the user. During analysis, the code was downloading a legitimate software unrelated to provided functionality, suggesting it is a research-like demonstration.\n\n\n---\n\nCategory: MALICIOUS - The campaign has clearly malicious intent, like infostealers.\n\n\nCampaign: 2026-08-rc4-secure\n\n\nReasons (based on the campaign):\n\n\n - Downloads and executes a remote executable.\n\n\n - modify-system-without-consent\n\n\n - action-hidden-in-lib-usage\n\n\n## Affected packages\n\n- `rc4-secure`\n\n## Remediation\n\nRefer to the advisory for the patched release.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}