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Malicious code in rate-limit-mini (RubyGems)

Type: advisorySource: OSV1 source record

RubyGems runs this gem's native extension script `ext/req_throttle_mini/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, forks twice into a detached process, waits 20 to 40 minutes and opens a reverse shell that connects `/bin/sh` to 45.138.12.177 on TCP port 8090. The shell reconnects every 30 seconds. 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 (edfe870cadc07265c0d6144de3019e30aa801b82e20f54e2fd309cc1eae7e4d0) The gem's native extension script ext/extconf.rb base64-decodes an embedded Ruby payload, writes it to a randomly named file under the system temporary directory, and spawns it with the Ruby interpreter before invoking the normal mkmf build. The decoded payload opens a TCP connection to 45.138.12.177:8090 and bridges /bin/sh to the socket in a reconnect loop, giving a remote operator interactive shell access on the installer's host at `gem install` time. The use of a base64-encoded Ruby blob inside extconf.rb has no build-system purpose and serves to evade casual revi

Announced Source revision 1
Original source ↗

MAL-2026-17567

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:MAL-2026-17567

rate-limit-mini

Source reference: /affected/0/package/name

Affected versions
1.0.0

Source reference: /affected/0/versions

1.0.1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "rate-limit-mini",
      "purl": "pkg:gem/rate-limit-mini",
      "ecosystem": "RubyGems"
    },
    "versions": [
      "1.0.0",
      "1.0.1"
    ],
    "database_specific": {
      "cwes": [
        {
          "name": "Embedded Malicious Code",
          "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."
        }
      ],
      "source": "https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/rate-limit-mini/MAL-2026-17567.json",
      "indicators": {
        "evidence_files": [
          {
            "path": "ext/req_throttle_mini/extconf.rb",
            "tlsh": "d60170534783290e23c186ee6b3d81508c6aceca53211a774285c1f5c28cab99f2bcb3",
            "sha256": "6f0cefe81dc6ab196d02f1e3d79677c48aa2a9d81c9941bcbaac1e9bd7fd4660"
          }
        ]
      }
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#85926 · Revision 1
Added to Heist Feed
Publisher date
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