MAL-2026-17783

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/defi-yield-calculator/MAL-2026-17783.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17783
Published
2026-10-11T13:45:29Z
Modified
2026-10-11T14:30:06Z
Summary
Malicious code in defi-yield-calculator (RubyGems)
Details

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

Source: amazon-inspector (ee8b3e50479b61d2ff6e2f5a19de20473cf8fc3c91f99945aff51f112a617192)

The gem ships an ext/extconf.rb that base64-decodes an embedded Ruby payload and runs it via eval inside a double-forked, detached, stdio-nulled background process after a 20–40 minute sleep. Execution is gated by anti-analysis checks that skip CI runners, ephemeral/sandbox hostnames, generated analyst usernames, common analysis working directories, low-uptime hosts, and hosts missing developer artifacts (~/.ssh, ~/.gitconfig, ~/.gem/credentials, ~/.bundle, ~/.npmrc), so the payload only fires on real developer machines. The decoded payload opens a TCPSocket to the hardcoded host 45.138.12.177 on port 8089 and bidirectionally pipes it to /bin/sh in an infinite reconnect loop, giving a remote operator persistent interactive shell access to the installer's host. The gemspec presents the package as a 'defi yield calculator' with a trivial lib stub exposing only VERSION/build_id/healthy?, the README is copied from an unrelated 'bitcoin-rpc-lite' project, and create_makefile targets 'bitcoin_rpc_lite_native' despite no C/C++ sources being shipped — the native-extension declaration exists solely to trigger the dropper during gem install.

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-021347",
            "import_time": "2026-10-11T14:17:58.055811336Z",
            "modified_time": "2026-10-11T13:45:29Z",
            "sha256": "ee8b3e50479b61d2ff6e2f5a19de20473cf8fc3c91f99945aff51f112a617192",
            "source": "amazon-inspector",
            "versions": [
                "0.9.1"
            ]
        }
    ]
}
References
Credits

Affected packages

RubyGems / defi-yield-calculator

Package

Name
defi-yield-calculator
Purl
pkg:gem/defi-yield-calculator

Affected ranges

Affected versions

0.*
0.9.1

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": [
        {
            "path": "ext/defi_yield_calculator/extconf.rb",
            "sha256": "10218e975f54a4f11fe3954e1b584a5f05054003bf5773c3c2b8cceaa74ba763",
            "tlsh": "9751775acf8359e55aa1c0c045798012faa3ab0a50646875f3ee0868ff59b26c0f12fe"
        },
        {
            "path": "metadata.yaml",
            "sha256": "006f9133255c87219662453c5940dcbc1ae5abe7d4cc7a6a4809a1cf0a7f4a12",
            "tlsh": "4d21614065c3e476fc02e3d7a8402307e393d95cbe9a7a40b69785dba3845697747471"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/defi-yield-calculator/MAL-2026-17783.json"