MAL-2026-17787

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/evm-tx-decoder/MAL-2026-17787.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17787
Published
2026-10-11T13:47:20Z
Modified
2026-10-11T14:30:07Z
Summary
Malicious code in evm-tx-decoder (RubyGems)
Details

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

Source: amazon-inspector (e478aa0270779720106fc6169e89fde089af352214fc720fbf8c284d51415f59)

The gem's native-extension build script ext/extconf.rb decodes a base64-embedded Ruby payload and executes it via eval inside a double-forked, detached child (Process.setsid, Process.detach). The payload opens a TCPSocket to the hardcoded bare-IP C2 at 45.138.12.177:8089 and connects it bidirectionally to /bin/sh via IO.popen and IO.copy_stream, yielding an interactive remote shell on the installer host at gem install time. Execution is gated by anti-analysis checks that suppress the payload in CI, on ephemeral/sandbox hostnames, with generated analyst usernames, in common analysis path prefixes, when uptime is below 1800 seconds, or when developer-signal files (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle) are absent, before sleeping a randomized 1200+rand(1200) seconds and launching the shell. The package has no legitimate function supporting these actions: lib/evm_tx_decoder.rb is a 243-byte stub returning 'ok'/true, the README text references an unrelated bitcoin_rpc_lite project, and extconf.rb calls create_makefile('bitcoin_rpc_lite_native') while shipping no C/C++ sources, so the native-build pretext is a cover story for the install-time backdoor.

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-021359",
            "import_time": "2026-10-11T14:17:59.127383923Z",
            "modified_time": "2026-10-11T13:47:20Z",
            "sha256": "e478aa0270779720106fc6169e89fde089af352214fc720fbf8c284d51415f59",
            "source": "amazon-inspector",
            "versions": [
                "0.9.1"
            ]
        }
    ]
}
References
Credits

Affected packages

RubyGems / evm-tx-decoder

Package

Name
evm-tx-decoder
Purl
pkg:gem/evm-tx-decoder

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/evm_tx_decoder/extconf.rb",
            "sha256": "10218e975f54a4f11fe3954e1b584a5f05054003bf5773c3c2b8cceaa74ba763",
            "tlsh": "9751775acf8359e55aa1c0c045798012faa3ab0a50646875f3ee0868ff59b26c0f12fe"
        },
        {
            "path": "lib/evm_tx_decoder.rb",
            "sha256": "2a64978f5ee8393abbf5da13fd56f43f9134390b2fdda5912d374f4420f69939",
            "tlsh": "c7d0979d433e3820803e4421a4eceec79fe8203243501024a92d52c5461323e233be71"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/evm-tx-decoder/MAL-2026-17787.json"