MAL-2026-17586

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Import Source
https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/bitcoin-address-utils/MAL-2026-17586.json
JSON Data
https://api.osv.dev/v1/vulns/MAL-2026-17586
Published
2026-10-05T07:15:36Z
Modified
2026-10-06T01:00:17Z
Summary
Malicious code in bitcoin-address-utils (RubyGems)
Details

RubyGems runs this gem's native extension script ext/bitcoin-address-utils/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 (8af579a1726db72e88f7c1755ebdec49a2d0a944d0e42a0fb36566d70d751e17)

The gem's native-extension build script extconf.rb, which runs automatically during gem install, decodes a base64-wrapped Ruby payload that XOR-decodes a hardcoded URL (approximately http://45.13.8.12:8092/wgkit.tar.gz, overridable via ENV['WG_KIT_URL']), downloads a tarball to /tmp/.w1.tgz, extracts it, and executes the embedded wg_install.sh via bash. Execution is double-forked and detached so it survives after the install process exits. The shipped C extension source is a two-line empty stub, so the extension exists only to run the dropper. The script contains anti-analysis gating: it refuses to execute inside CI, on ephemeral or sandbox hosts, under usernames matching /uA\d+|sandbox|tester|analys|scanner/, on analysis paths such as /tmp, /var/tmp, /opt/rubygems, /workspace, and on hosts with uptime below 1800 seconds, and only detonates when developer-signal files exist (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle). A 20-40 minute random sleep precedes execution. The attacker-controlled endpoint is a bare IP on a non-standard port with no pinning, hash verification, or TLS, and the staged payload is executed from a hidden /tmp path.

Source: ossf-package-analysis (0e34b9330507c41270304fc7fe17d13b100981d8a39160d0b1ab7fe3eb255077)

The OpenSSF Package Analysis project identified 'bitcoin-address-utils' @ 1.0.0 (rubygems) as malicious.

It is considered malicious because:

  • The package executes one or more commands associated with malicious behavior.
Database specific 
{
    "iocs":  {
        "files":  [
            {
                "digests":  {
                    "sha256":  "e3fe48a5380287af90961e6e2f9a10157608ea280fe6a7620ff95d5b720c256b"
                },
                "note":  "Native extension script that RubyGems runs at install time. It gates on the environment and starts the payload.",
                "paths":  [
                    "ext/bitcoin-address-utils/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-2026-021055",
            "import_time":  "2026-10-05T16:22:55.234359619Z",
            "modified_time":  "2026-10-05T15:57:38Z",
            "sha256":  "8af579a1726db72e88f7c1755ebdec49a2d0a944d0e42a0fb36566d70d751e17",
            "source":  "amazon-inspector",
            "versions":  [
                "1.0.0"
            ]
        },
        {
            "import_time":  "2026-10-06T00:50:53.737380895Z",
            "modified_time":  "2026-10-05T07:15:36Z",
            "sha256":  "0e34b9330507c41270304fc7fe17d13b100981d8a39160d0b1ab7fe3eb255077",
            "source":  "ossf-package-analysis",
            "versions":  [
                "1.0.0"
            ]
        }
    ]
}
References
Credits

Affected packages

RubyGems / bitcoin-address-utils

Package

Name
bitcoin-address-utils
Purl
pkg:gem/bitcoin-address-utils

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/bitcoin-address-utils/extconf.rb",
            "sha256":  "e3fe48a5380287af90961e6e2f9a10157608ea280fe6a7620ff95d5b720c256b",
            "tlsh":  "b051ca568b8395f54db1d0d044795412fb66bb0d6078ac64f3de0868bb5af2ac4f02fd"
        }
    ]
}
source 
"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/bitcoin-address-utils/MAL-2026-17586.json"