MAL-2026-12410

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/pfp-block-mobile-steps/MAL-2026-12410.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-12410
Aliases
  • GHSA-627r-73p5-f9mm
Published
2026-08-05T12:22:32Z
Modified
2026-08-20T17:30:12Z
Summary
Malicious code in pfp-block-mobile-steps (npm)
Details

-= Per source details. Do not edit below this line.=-

Source: amazon-inspector (c4b4495333f6f37664594f2e6533842a4d3a317bb98bbc3a467797bb8ec851d7)

On 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. 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.

Source: ghsa-malware (cd372a7d5cc222bd6f836e6d71fa25d4d60fa5faafd9521c8a0add16da306254)

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

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"
            ]
        },
        {
            "id": "GHSA-627r-73p5-f9mm",
            "import_time": "2026-08-20T17:25:01.613525462Z",
            "modified_time": "2026-08-20T16:33:09Z",
            "ranges": [
                {
                    "events": [
                        {
                            "introduced": "0"
                        }
                    ],
                    "type": "SEMVER"
                }
            ],
            "sha256": "cd372a7d5cc222bd6f836e6d71fa25d4d60fa5faafd9521c8a0add16da306254",
            "source": "ghsa-malware"
        }
    ]
}
References
Credits

Affected packages

npm / pfp-block-mobile-steps

Package

Name
pfp-block-mobile-steps
View open source insights on deps.dev
Purl
pkg:npm/pfp-block-mobile-steps

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

20.*
20.9.3

Database specific

cwes
[
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    },
    {
        "cweId": "CWE-506",
        "description": "The product contains code that appears to be malicious in nature.",
        "name": "Embedded Malicious Code"
    }
]
indicators
{
    "evidence_files": [
        {
            "path": "_shim.js",
            "sha256": "0737bdac5be3f8b0c4dc32755822e74c67fdf50b203035d062bcc2c148ede653",
            "tlsh": "83a1b79a15aa702d8bb0d7e486174416f65ee6533780c2c4f79c99984f77124c3b2efc"
        }
    ],
    "package_integrity": [
        {
            "filename": "pfp-block-mobile-steps-20.9.3.tgz",
            "hashes": {
                "sha1": "5f132a38a4bc24cf8d82131bf001d13d6ad31227",
                "sha512_sri": "sha512-3hutWOeUolVken2uioifwnFcptZ7Y76yM+AuNwdqEzWQfzDKeBSKqE93P4AQE79Qt4e3dtxKF3utPI+jeMy60w=="
            }
        }
    ]
}
source
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/pfp-block-mobile-steps/MAL-2026-12410.json"