MAL-2026-19157

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/cheesebox/MAL-2026-19157.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-19157
Published
2026-11-12T15:51:40Z
Modified
2026-11-12T16:30:05Z
Summary
Malicious code in cheesebox (RubyGems)
Details

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

Source: amazon-inspector (5b03698e5384db9f041d0e2caa51db10abc0d0dcbfc1e5e77b795acc4d8cec76)

The gem declares mkrf_conf.rb as a native extension in its gemspec, causing it to execute automatically during gem install. On execution the script reads installer-side system files (/etc/passwd, /etc/hosts, /etc/resolv.conf) and collects host identifiers (hostname, username, home directory, current working directory), then opens a TLS TCPSocket to the hardcoded Burp Collaborator subdomain xwx31i3e80kbj4h1s7wnh8yklbrdf33s.oastify.com on port 443 and POSTs the collected data as JSON. The destination is an attacker-controlled out-of-band interaction host, not any infrastructure related to the gem's declared purpose, and the data read is unrelated to building a native extension (no mkmf probing, no compilation of shipped sources).

Database specific 
{
    "malicious-packages-origins": [
        {
            "id": "IN-MAL-2026-022648",
            "import_time": "2026-11-12T16:13:53.337029441Z",
            "modified_time": "2026-11-12T15:51:40Z",
            "sha256": "5b03698e5384db9f041d0e2caa51db10abc0d0dcbfc1e5e77b795acc4d8cec76",
            "source": "amazon-inspector",
            "versions": [
                "10.0.1"
            ]
        }
    ]
}
References
Credits

Affected packages

RubyGems / cheesebox

Package

Name
cheesebox
Purl
pkg:gem/cheesebox

Affected ranges

Affected versions

10.*
10.0.1

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/mkrf_conf.rb",
            "sha256": "298d01af34f1ff9361870ff26078aff9a19249828e81056e2f3b877268124bc8",
            "tlsh": "ad11328857897cf06b6288efd14c20826493ce5aca452462ff9944a0cfadb3c33319f9"
        }
    ],
    "package_integrity": [
        {
            "filename": "cheesebox-10.0.1.gem",
            "hashes": {
                "sha256": "c020e06f85c8f9ad442392d84b8b0e9608b19484c8e81e9e058e999568501e9a"
            }
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/cheesebox/MAL-2026-19157.json"