MAL-2026-17591

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/crylto-toolbox/MAL-2026-17591.json
JSON Data
https://api.test.osv.dev/v1/vulns/MAL-2026-17591
Published
2026-10-05T09:30:00Z
Modified
2026-10-05T23:45:06Z
Summary
Malicious code in crylto-toolbox (RubyGems)
Details

RubyGems runs this gem's native extension script ext/crylto-toolbox/extconf.rb during gem install. The script exits without action on CI runners and sandboxes, based on CI environment variables, the hostname, the username and the working directory. It continues if the system uptime is over 30 minutes and the home directory holds .ssh, .gitconfig, .npmrc, .gem/credentials or .bundle. It then decodes a Base64 Ruby payload and forks twice into a detached process. After 20 to 40 minutes the payload downloads http://45.138.12.177:8092/wgkit.tar.gz to /tmp/.w1.tgz with curl, extracts it to /tmp/.w1/, runs wg_install.sh with bash and deletes both. The payload stores the URL XOR-encoded with the key usv\x9a. The Ruby code in lib/ is a decoy. The RubyGems account reqthrottle_3474 published this gem and 41 others with the same loader on 2026-10-05.

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

Source: amazon-inspector (4362469cec139567ebe3c986d7f2eca2dda837ecff87373d14d9cfbedf81e6b0)

The gem's extconf.rb is not a native-extension build script. It contains a base64-encoded Ruby payload that, after gating on anti-analysis checks, downloads and executes an attacker-controlled shell script at install time. The anti-analysis gate inspects CI environment variables, hostname patterns (uvm/firecracker/sandbox/vagrant), username patterns (uA\d+, sandbox/tester/analys/scanner), working-directory prefixes (/tmp, /var/tmp, /opt/rubygems, /workspace), /proc/uptime (>1800s), and the presence of developer artifacts (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle) to restrict execution to real developer machines. When the gate passes, extconf.rb forks a detached process that sleeps 20-40 minutes, then reconstructs a URL by XOR-decoding a hex blob with key 'usv\x9a' resolving to http://45.138.12.177:8092/wgkit.tar.gz, downloads the archive to /tmp/.w1.tgz with no TLS and no integrity check, extracts it, and runs bash /tmp/.w1/wg_install.sh via system(). The package name is a typo of 'crypto-toolbox'. The combination of obfuscated URL reconstruction, bare-IP plaintext HTTP delivery, detached delayed execution, sandbox-evasion gating keyed on developer-only artifacts, and execution of arbitrary attacker-supplied bash during gem install is an install-time dropper on the installer's host.

Database specific 
{
    "iocs": {
        "files": [
            {
                "digests": {
                    "sha256": "3ff1c72958a7d17e086f83a72087093c06bd38c9602b6e202a6424ee6ff59c27"
                },
                "note": "Native extension script that RubyGems runs at install time. It gates on the environment and starts the payload.",
                "paths": [
                    "ext/crylto-toolbox/extconf.rb"
                ],
                "source": "PACKAGE_ARCHIVE"
            },
            {
                "note": "Second-stage archive and install script downloaded and run by the payload.",
                "paths": [
                    "/tmp/.w1.tgz",
                    "/tmp/.w1/wg_install.sh"
                ],
                "source": "DROPPED"
            }
        ],
        "ips": [
            "45.138.12.177"
        ],
        "urls": [
            "http://45.138.12.177:8092/wgkit.tar.gz"
        ]
    },
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-021048",
            "import_time": "2026-10-05T16:22:54.762337895Z",
            "modified_time": "2026-10-05T15:56:37Z",
            "sha256": "4362469cec139567ebe3c986d7f2eca2dda837ecff87373d14d9cfbedf81e6b0",
            "source": "amazon-inspector",
            "versions": [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

RubyGems / crylto-toolbox

Package

Name
crylto-toolbox
Purl
pkg:gem/crylto-toolbox

Affected ranges

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

Affected versions

1.*
1.0.0

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": "ext/crylto-toolbox/extconf.rb",
            "sha256": "3ff1c72958a7d17e086f83a72087093c06bd38c9602b6e202a6424ee6ff59c27",
            "tlsh": "c351cb56cb8395f54db1d0d044355412fb667b0d6068ac64f3de0868bb5af2ac4f02fd"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/crylto-toolbox/MAL-2026-17591.json"