CVE-2025-40778およびCVE-2025-40780：BIND 9におけるキャッシュ毒化の脆弱性

Ruslan Mikhalov Chief of Threat Research at SOC Prime

CVE-2025-40778およびCVE-2025-40780：BIND 9におけるキャッシュ毒化の脆弱性

Detection stack

AIDR
Alert
ETL
Query

脅威レポート
検出
シミュレーション

分析

CVE-2025-40778 と CVE-2025-40780 は、ISP、企業、政府ネットワークで広く使用されている世界で最も広く展開されているDNSサーバーであるBIND 9の高深刻度のキャッシュ中毒の脆弱性です。2025年10月22日、ISCは3つのリモートで悪用可能なBIND 9の欠陥（CVE-2025-40778、CVE-2025-40780（いずれもCVSS 8.6）、CVE-2025-8677（CVSS 7.5））を開示しました。これらはすべて、認証なしでネットワーク経由でアクセス可能です。CVE-2025-40778は、要求されていないリソースレコードを過度に許容する処理から生じ、再帰的リゾルバがbailiwick規則に違反するデータをキャッシュすることを許可し、攻撃者が制御するインフラストラクチャにユーザーをリダイレクトするキャッシュの中毒を可能にします。CVE-2025-40780はソースポートとクエリIDのランダム化を弱め、攻撃者が値を予測し、トランジット中の偽の応答を「勝ち取る」ことを容易にします。CVE-2025-8677はこれらの問題を補完し、誤形成されたDNSKEYレコードを悪用してCPU使用率を100％に押し上げ、DoS状態を作成し、キャッシュ中毒キャンペーンを増幅します。

調査

CVE-2025-40778、CVE-2025-40780、およびCVE-2025-8677の調査は、DNSインフラストラクチャの完全なインベントリから始めるべきです。内部、ラボ、および「忘れられた」インスタンスを含むすべてのBIND 9再帰的リゾルバを特定し、各サーバーをその正確なBINDバージョンと役割（再帰的、権威的、フォワーダー、検証）にマッピングします。ISCによれば、影響を受けたデプロイメントは9.18.41、9.20.15、または9.21.14（またはプレビュー9.18.41-S1 / 9.20.15-S1）にアップグレードする必要があります。CVE-2025-40778の場合、キャッシュ中毒の兆候を探します：問い合わせられたことのない名前のキャッシュレコード、予期しない追加レコード、または計画されていないDNS更新のない高価値ドメインの突然のIP変更。CVE-2025-40780の場合、エントロピーの悪用を探します：信頼できないIPからの偽装や繰り返しの応答の急増、同様のクエリの高容量、およびクライアント側のTLSやブラウザの警告。CVE-2025-8677はDoSを引き起こす可能性があるため、繰り返しのSERVFAIL/タイムアウト、奇妙なDNSSECゾーン、特定のクエリに関連するCPUやレイテンシのスパイクを監視します。

緩和策

CVE-2025-40778、CVE-2025-40780、およびCVE-2025-8677に対して、ISCは 回避策がない とリストしています — BIND 9をパッチすることが主要な防御策です。再帰的リゾルバは9.18.41、9.20.15、または9.21.14、あるいはプレビュービルド9.18.41-S1 / 9.20.15-S1にアップグレードし、ディストリビューションパッケージがISCのガイダンスに一致することを確認します。同時に、信頼されたクライアントと内部ネットワークへの再帰を制限し、インターネット上のオープンリゾルバを避け、追加のレコードを最小限に受け入れて厳格なbailiwickチェックを実施することにより、リゾルバの設定を強化します。再帰的リゾルバでDNSSEC検証を有効にし、改ざんの兆候として障害率を監視し、疑わしいDNSトラフィックや不正なリゾルバ活動をフィルタリングし、レート制限するためのネットワークレベルのコントロールを追加します。最後に、重要なドメインのIP変更の急増、SERVFAIL/タイムアウトの急増、繰り返しのクエリ、またはCVE-2025-8677の悪用を示す可能性のあるDNSKEYの取り扱いの異常についてアラートを設定して、監視を強化します。

対応

DNSインフラがターゲットとなっているか、CVE-2025-40778、CVE-2025-40780、またはCVE-2025-8677を通じて侵害された可能性がある場合、DNSサービスを安定化し保護することから始めます。可能であれば、パッチされたセカンダリリゾルバにフェイルオーバーし、内部での分析を維持しつつ、脆弱なものへの外部アクセスを制限します。リゾルバのキャッシュをフラッシュして中毒されたエントリを削除し、再利用する前に権威あるソースで高価値の内部ゾーンのレコードを検証します。重要なドメイン（IdP、メール、VPN、管理ポータル、支払い用）のIP解決とDNSSECステータスをレジストラや変更ログと照らし合わせてDNSの完全性を検証します。BINDログ、システムログ、およびパケットキャプチャを保存して、フィッシングサイト、偽SSOポータル、または不正なメールサーバーへのリダイレクトの証拠を見つけるために鑑識レビューを行います。パッチ適用後、強化された設定で再展開し、SIEMの検出を更新し、DNSキャッシュ中毒のリスクと新しい安全策についてチームに説明します。

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無料で参加

Name	Descripiton
PHPSESSID	Preserves user session state across page requests. Cookie generated by applications based on the PHP language. This is a general purpose identifier used to maintain user session variables. It is normally a random generated number, how it is used can be specific to the site, but a good example is maintaining a logged-in status for a user between pages.
sp_i	Used to store information about authenticated User.
sp_r	Used to store information about authenticated User.
sp_a	Used to store information about authenticated User.

Name	Descripiton
tuuid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
tuuid_last_update	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
um	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
umeh	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
na_sc_x	Used by the social sharing platform AddThis to keep a record of parts of the site that has been visited in order to recommend other parts of the site.
APID	Collects anonymous data related to the user's visits to the website.
IDSYNC	Collects anonymous data related to the user's visits to the website.
_cc_aud	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_cc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_dc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_id	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
dpm	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
acs	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
clid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
KRTBCOOKIE_#	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PUBMDCID	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PugT	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
ssi	Registers a unique ID that identifies a returning user's device. The ID is used for targeted ads.
_tmid	Registers a unique ID that identifies the user's device upon return visits. The ID is used to target ads in video clips.
wam-sync	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
wui	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
AFFICHE_W	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
B	Collects anonymous data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The registered data is used to categorise the users' interest and demographical profiles with the purpose of customising the website content depending on the visitor.
1P_JAR	These cookies are used to gather website statistics, and track conversion rates.
APISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
HSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
NID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SAPISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SIDCC	Security cookie to protect users data from unauthorised access.
SSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
__utmx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.
__utmxx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.

Name	Descripiton
_hjid	Hotjar cookie. This cookie is set when the customer first lands on a page with the Hotjar script. It is used to persist the random user ID, unique to that site on the browser. This ensures that behavior in subsequent visits to the same site will be attributed to the same user ID.
_hjIncludedInSample	This cookie is associated with web analytics functionality and services from Hot Jar, a Malta based company. It uniquely identifies a visitor during a single browser session and indicates they are included in an audience sample.
intercom-id-[xxx]	This cookie is used by Intercom as a session so that users can continue a chat as they move through the site.
intercom-session-[xxx]	Used to keeping track of sessions and remember logins and conversations.
demdex	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
CookieConsent	Stores the user's cookie consent state for the current domain.
__cfduid	Used by the content network, Cloudflare, to identify trusted web traffic.
ss	These cookies enable the website to provide enhanced functionality and personalisation . They may be set by us or by third party providers whose services we have added to our pages. These services may include the Live Chat facility, Contact Us form(s), the Product Quotation forms and submission process, and the Email Newsletter sign up functionality .

Name	Descripiton
_ga	This cookie name is asssociated with Google Universal Analytics - which is a significant update to Google's more commonly used analytics service. This cookie is used to distinguish unique users by assigning a randomly generated number as a client identifier. It is included in each page. Registers a unique ID that is used to generate statistical data on how the visitor uses the website. request in a site and used to calculate visitor, session and campaign data for the sites analytics reports. By default it is set to expire after 2 years, although this is customisable by website owners.
_gat	Used by Google Analytics to throttle request rate. This cookie name is associated with Google Universal Analytics, according to documentation it is used to throttle the request rate - limiting the collection of data on high traffic sites. It expires after 10 minutes.
_gid	This cookie name is asssociated with Google Universal Analytics. This appears to be a new cookie and as of Spring 2017 no information is available from Google. It appears to store and update a unique value for each page visited. Registers a unique ID that is used to generate statistical data on how the visitor uses the website.
IDE	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
r/collect	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
test_cookie	Used to check if the user's browser supports cookies.
collect	Used to send data to Google Analytics about the visitor's device and behaviour. Tracks the visitor across devices and marketing channels.
ads/user-lists/#	These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites.
c	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
khaos	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
put_#	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpb	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpx	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
tap.php	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.