npmとmavenのライフサイクル攻撃対応プロキシ

ライフサイクル攻撃対応プロキシ

npmやmavenのライブラリが汚染されているかもしれないっていう不安から、自前のプロキシサーバを構築して対応しようと考え、以下の構成で実装してみました。

構成

[ 開発PC / CI/CD ]
       │ (mvn install / npm install)
       ▼
[ 検疫プロキシ (Python) ]  ※ここで「14日以内」をチェックして弾く
       │ (安全なら転送)
       ▼
[ Nexus OSS (Proxy) ]
       │ (キャッシュがなければ取得)
       ▼
[ 外部 (Maven Central / npmレジストリ) ]

dockerの設定

docker-compose.yml

services:
  # Nexus本体
  nexus:
    image: sonatype/nexus3:latest
    container_name: nexus
    restart: always
    volumes:
      - ./.docker/nexus-data:/nexus-data
    ports:
      - "61012:8081" # Nexus管理画面 兼 キャッシュサーバー
    networks:
      - proxy-net

  # 自作の検疫プロキシ（Python）
  quarantine-proxy:
    image: python:3.11-slim
    container_name: quarantine-proxy
    restart: always
    ports:
      - "61013:8080" # クライアント接続ポート
    volumes:
      - ./proxy_script:/app
    working_dir: /app
    command: sh -c "pip install flask requests && python app.py"
    networks:
      - proxy-net
    depends_on:
      - nexus

networks:
  proxy-net:

volumes:
  nexus-data:

あらかじめ、以下のディレクトリは200にしておきます。（nexusがうまく動かなかった）

sudo chown -R 200:200 ./.docker/nexus-data

python→nexus接続ユーザの作成

pythonスクリプト

※このスクリプトはあくまでサンプルですので、参考程度という事でお願いします。
正常動作しなかった場合はご了承ください。

./proxy_script/app.py

import base64
from datetime import datetime, timedelta
import re
from flask import Flask, Response, request
import requests

app = Flask(__name__)

# ==========================================
# 【設定情報】
# ==========================================
NEXUS_URL = "http://192.168.x.x:61012"
PROXY_USER = "proxy-user"
PROXY_PASSWORD = "xxxxxxx"

HOLD_DAYS = 14  # 検疫期間（14日間）

# Nexusへの認証ヘッダーを事前に作成 (Basic認証)
token = base64.b64encode(f"{PROXY_USER}:{PROXY_PASSWORD}".encode("utf-8")).decode(
    "utf-8"
)
NEXUS_HEADERS = {"Authorization": f"Basic {token}"}


# ==========================================
# 【検疫ロジック】公開日数をチェックする関数
# ==========================================
def is_safe_component(repo_type, path):
    try:
        # --- ① npm の検疫判定 ---
        if repo_type == "npm":
            # パスからパッケージ名とバージョンを抽出する正規表現
            # 例: /repository/npm-public/vue/-/vue-3.5.0.tgz -> name: vue, version: 3.5.0
            match = re.search(r"([^/]+)/-/.*-(\d+\.\d+\.\d+(-\w+)?)\.tgz", path)
            if not match:
                return True  # 該当のメタデータ構造でない場合は一旦通す（またはメタデータjson）

            package_name, version = match.group(1), match.group(2)

            # スコープ付きパッケージ（例: @types/node）のハンドリング
            if "/@" in path:
                scope_match = re.search(r"(@[^/]+/[^/]+)/-/.*", path)
                if scope_match:
                    package_name = scope_match.group(1)

            # npm公式APIに問い合わせ
            url = f"https://registry.npmjs.org/{package_name}"
            res = requests.get(url, timeout=5).json()
            time_str = res.get("time", {}).get(version)

            if time_str:
                # ISO 8601形式 (2026-06-19T...Z) をパース
                release_date = datetime.strptime(time_str[:10], "%Y-%m-%d")
                if datetime.now() - release_date < timedelta(days=HOLD_DAYS):
                    print(
                        f"[⚠️ BLOCK] npm: {package_name}@{version} はリリース後 {HOLD_DAYS} 日以内です。"
                    )
                    return False

        # --- ② Maven の検疫判定 ---
        elif repo_type == "maven":
            if not path.endswith((".jar", ".pom")):
                return True

            # 先頭の "/repository/リポジトリ名/" を取り除く
            match_maven = re.match(r"^/repository/[^/]+/(.*)$", path)
            maven_path = match_maven.group(1) if match_maven else path.lstrip("/")

            # Maven Central 本尊のURLを構築
            central_url = f"https://repo1.maven.org/maven2/{maven_path}"

            # Maven Central本体に直接 HEAD リクエストを送り、ファイルの正確なタイムスタンプを取得する
            headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64)"}
            central_res = requests.head(central_url, headers=headers, timeout=5)

            if central_res.status_code == 200:
                last_modified_str = central_res.headers.get("Last-Modified")
                if last_modified_str:
                    from email.utils import parsedate_to_datetime

                    release_date = parsedate_to_datetime(last_modified_str).replace(tzinfo=None)

                    if datetime.now() - release_date < timedelta(days=HOLD_DAYS):
                        print(f"[⚠️ BLOCK] Maven: {maven_path} はリリース後 {HOLD_DAYS} 日以内です。({release_date})")
                        return False
                    else:
                        print(f"[INFO] Maven: {maven_path} は14日以上経過しているため安全です。({release_date})")
                        return True

            # 安全側に倒して、検疫ブロックします
            print(f"[⚠️ BLOCK] Maven: {maven_path} は Maven Central 上に存在しない、または確認できないためブロックします。")
            return False

    except Exception as e:
        # APIエラー等の場合は安全側に倒してブロック
        print(f"[ERROR] 検疫チェック中にエラーが発生: {e}")
        return False

    return True

# ==========================================
# 【プロキシメイン処理】どんなパスでも一律で受け止める
# ==========================================
@app.route("/", defaults={"path": ""}, methods=["GET", "HEAD"])
@app.route("/<path:path>", methods=["GET", "HEAD"])
def catch_all(path):
    # 頭にスラッシュをつけて、重複するスラッシュ（//）を1つに綺麗に成形する
    full_path = "/" + path
    full_path = re.sub(r"//+", "/", full_path)

    match = re.match(r"^/repository/([^/]+)/(.*)$", full_path)
    if not match:
        target_url = f"{NEXUS_URL}{full_path}"
    else:
        repo_name = match.group(1)
        target_path = match.group(2)

        repo_type = "unknown"
        if "npm" in repo_name:
            repo_type = "npm"
        elif "maven" in repo_name:
            repo_type = "maven"

        if request.method in ["GET", "HEAD"]:
            if not is_safe_component(repo_type, full_path):
                return Response(
                    "🚫 [Quarantine] Access Denied: Under 14-day quarantine.",
                    status=403,
                )

        target_url = f"{NEXUS_URL}{full_path}"

    if request.query_string:
        target_url += f"?{request.query_string.decode('utf-8')}"

    try:
        # Nexusへリレー通信
        nexus_response = requests.request(
            method=request.method,
            url=target_url,
            auth=(PROXY_USER, PROXY_PASSWORD),
            stream=True,
            timeout=30,
        )

        if request.method == "HEAD":
            response = Response(
                status=nexus_response.status_code,
                content_type=nexus_response.headers.get("Content-Type"),
            )
            for key, value in nexus_response.headers.items():
                if key.lower() not in [
                    "content-length",
                    "transfer-encoding",
                    "connection",
                ]:
                    response.headers[key] = value
            return response

        # --- GETリクエストの処理 ---
        content_type = nexus_response.headers.get("Content-Type", "")
        if "application/json" in content_type and "/repository/" in full_path:
            proxy_root_url = request.host_url.rstrip("/")

            json_text = nexus_response.text
            modified_json_text = json_text.replace(NEXUS_URL, proxy_root_url)

            response = Response(
                modified_json_text,
                status=nexus_response.status_code,
                content_type=content_type,
            )
            return response

        response = Response(
            nexus_response.iter_content(chunk_size=10 * 1024),
            status=nexus_response.status_code,
            content_type=content_type,
        )
        return response

    except Exception as e:
        import traceback

        print(f"[🚨 CRITICAL ERROR]\n{traceback.format_exc()}")
        return Response("Internal Proxy Error", status=500)


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8080, debug=True)

動作確認 maven

クライアント設定

クライアント側では、~/.m2/settings.xmlを作成してプロキシ経由にします

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.2.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.2.0 https://maven.apache.org/xsd/settings-1.2.0.xsd">

  <mirrors>
    <mirror>
      <id>company-quarantine-mirror</id>
      <name>Company Quarantine Proxy Mirror</name>
      <url>http://192.168.x.x:61013/repository/maven-public/</url>
      <mirrorOf>*</mirrorOf>
    </mirror>
  </mirrors>

  <profiles>
    <profile>
      <id>quarantine-profile</id>
      <repositories>
        <repository>
          <id>central</id>
          <url>https://repo.maven.apache.org/maven2</url>
          <snapshots>
            <enabled>false</enabled>
          </snapshots>
        </repository>
      </repositories>
    </profile>
  </profiles>

  <activeProfiles>
    <activeProfile>quarantine-profile</activeProfile>
  </activeProfiles>

</settings>

jackson-databindで実験します。

• 3.1.4 は 2026/5/29 なので、今日（2026/6/20）より14以上前なので正常に取れる

% mvn dependency:get -Dartifact=tools.jackson.core:jackson-databind:3.1.4
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- dependency:3.6.1:get (default-cli) @ standalone-pom ---
[INFO] Resolving tools.jackson.core:jackson-databind:jar:3.1.4 with transitive dependencies
Downloading from company-quarantine-mirror: http://192.168.x.x:61013/repository/maven-public/tools/jackson/core/jackson-databind/3.1.4/jackson-databind-3.1.4.pom
Downloaded from company-quarantine-mirror: http://192.168.x.x:61013/repository/maven-public/tools/jackson/core/jackson-databind/3.1.4/jackson-databind-3.1.4.pom (18 kB at 52 kB/s)
＜中略＞
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.867 s
[INFO] Finished at: 2026-06-20T20:09:14+09:00
[INFO] ------------------------------------------------------------------------

• 3.2.0 は 2026/6/9 なので、今日（2026/6/20）より14日以内なので取れない

% mvn dependency:get -Dartifact=tools.jackson.core:jackson-databind:3.2.0
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- dependency:3.6.1:get (default-cli) @ standalone-pom ---
[INFO] Resolving tools.jackson.core:jackson-databind:jar:3.2.0 with transitive dependencies
Downloading from company-quarantine-mirror: http://192.168.x.x:61013/repository/maven-public/tools/jackson/core/jackson-databind/3.2.0/jackson-databind-3.2.0.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.873 s
[INFO] Finished at: 2026-06-20T20:08:26+09:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-dependency-plugin:3.6.1:get (default-cli) on project standalone-pom: Couldn't download artifact: org.eclipse.aether.resolution.DependencyResolutionException: Failed to read artifact descriptor for tools.jackson.core:jackson-databind:jar:3.2.0: The following artifacts could not be resolved: tools.jackson.core:jackson-databind:pom:3.2.0 (absent): Could not transfer artifact tools.jackson.core:jackson-databind:pom:3.2.0 from/to company-quarantine-mirror (http://192.168.x.x:61013/repository/maven-public/): status code: 403, reason phrase: FORBIDDEN (403) -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

動作確認 npm

クライアント設定

クライアント側では、.npmrcを作成してプロキシ経由にします

.npmrc

registry=http://192.168.x.x:61013/repository/npm-public/
//192.168.x.x:61013/repository/npm-public/:_auth=false

@aws-sdk/client-s3で実験します。

• 3.1063.0 は 15 days ago で14以上前なので正常に取れる

>npm install @aws-sdk/client-s3@3.1063.0

added 45 packages in 5s

7 packages are looking for funding
  run `npm fund` for details

• 3.1064.0 は 12 days ago で14日以内なので取れない

>npm install @aws-sdk/client-s3@3.1064.0
npm error code E403
npm error 403 403 FORBIDDEN - GET http://192.168.x.x:61013/repository/npm-public/@aws-sdk/client-s3/-/client-s3-3.1064.0.tgz
npm error 403 In most cases, you or one of your dependencies are requesting
npm error 403 a package version that is forbidden by your security policy, or
npm error 403 on a server you do not have access to.
npm error A complete log of this run can be found in: C:\Users\xxxxx\AppData\Local\npm-cache\_logs\2026-06-20T11_44_02_306Z-debug-0.log

あとがき

14日とした理由は特にないが、一旦これで運用してみて課題がありそうだったら考える予定です