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2要素認証 (2FA) の侵害:Microsoft アカウントの乗っ取り

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17
Feb 2021
17
Feb 2021
2要素認証(2FA)がハッキングされた場合、どうなるのでしょうか?セキュリティ層が侵害され、サイバー犯罪者がセキュリティスタックを迂回した場合、どうなるのでしょうか?このブログでは、DarktraceのMicrosoft 365コネクタがSaaSアカウントの完全な乗っ取りを自動検知し、攻撃に対する詳細な調査を開始した方法を説明します。

二要素認証(2FA)とは?

2要素認証 (2FA) は今や、ほぼ3分の1の企業が採用しています。これはユーザーに対し、アカウントにログインする際に、複数の識別要素の提示を要求する方法です。これによりサイバー犯罪者が単にパスワード情報を使ってシステムをハックするのを防ぐことができます。アカウントへのアクセスを得るには、さらなるセキュリティレイヤー、たとえば生体認証(生来の特徴)、個人情報(知識)、あるいは電話やEメールに送られたコード(所有物)を必要とします。

2FA が侵害されたらどうなるか?

Darktraceは最近、まさにこのようなケースを観測しました。Microsoft 365 アカウントが乗っ取られ、攻撃者は一時的に認証設定を変更してSMSコードが彼らの電話に送信されるようにしたのです。この攻撃はユーザーアクティビティに紛れ込んで検知されないようにしようとしました。しかし、Darktraceはユーザーの挙動のかすかな異常からこのアカウントの侵害を特定することができた。これには、疑わしいログイン、不審なEメールルールの変更、ファイル削除などが含まれていました。

このようなSaaSベースの攻撃は急激に増加しています。多くの企業がリモートビジネスのためにますますSaaSプラットフォームに依存するなかで、これは驚くに値しません。Microsoft 365は現在、これらの企業のEメール、ユーザー管理、ファイルストレージおよび共有のために幅広く使われています。これによりアタックサーフェスは拡大し、サイバー犯罪者にとっての格好の機会となっています。SaaSプラットフォームは多くの場合サイロ化されており、セキュリティチームはこれらに対する可視性を持っていないことが多く、複数のプラットフォーム間でのイベントの相関付けに苦労しています。

Darktraceの Cyber AIは、SaaS環境全体を保護し、Microsoft 365およびAzureプラットフォームに対して完全なカバレッジを提供することができます。今回取り上げる事例では、お客様はMicrosoft 365を使っていました。攻撃は他のすべてのセキュリティツールをすり抜けたにも関わらず、DarktraceのMicrosoft 365コネクタにより識別され、Cyber AI Analystにより調査されました。Cyber AI Analystは世界初のAI調査テクノロジーであり、セキュリティインシデントを自動的にトリアージし、解釈し、インシデントの全貌をレポートします。

2FAを使ってMicrosoftアカウントがどのように侵害されたか

最近、ある企業の財務部のユーザーのアカウントが侵害されました。この企業にはMicrosoft 365ユーザーが約10,000ユーザーいます。最初の感染はおそらく、この従業員がフィッシングメールの悪意のあるリンクをクリックしたことから発生したと思われます。

図1: 攻撃のタイムライン

Darktraceは米国およびガーナの不審なロケーションからのMicrosoft 365アカウントへの疑わしいログインを検知し始めました。これらのログインは多要素認証(MFA)セキュリティをパスすることに成功しました。攻撃者は密かにユーザーの設定を操作し、登録された電話番号を変更して認証のためのテキストメッセージが彼らに直接送られるようにしたのです。

図2:Darktraceの専用SaaSコンソールに表示されたMicrosoft365内の不審なアクティビティ

2FAはいくつかの戦術で破ることができます。SIMスワップ攻撃や悪意あるOAuthアプリケーションの使用によりハッキングされることがあります。また、攻撃者はフィッシング攻撃やソーシャルエンジニアリング攻撃を使って、標的となったユーザーがフィッシングページに入ると同時にリアルタイムにワンタイムパスワードを使用することさえあります。

この不審なログインに続いて、Darktraceは攻撃者がユーザーのアカウントに対するEメールルールを変更したことを観測しました。また、複数の共有受信箱の設定も変更し、これには与信管理に関係するものも含まれていました。

この間、攻撃者がユーザーの受信箱内の複数のEメールにアクセスしていることが確認されています。攻撃者は受信箱を漁って機密性のデータを探そうとしていたか、あるいはユーザーの通常のアクティビティやメールの書き方を知ることにより、アカウントの持ち主を装ったもっともらしいフィッシングメールを作成しようとしていたのかもしれません。また、攻撃者はこのユーザー宛ての複数のEメールを削除し、痕跡を消そうとしていました。

この組織の他のセキュリティスタックからはこの脅威が見えていませんでしたが、DarktraceのMicrosoft 365コネクタはこの異常な動作を検知し、Cyber AI Analystによる自動調査が開始されました。これに続いてセキュリティチームが対応し、攻撃者がいくつかの重要な共有メールボックスを悪用する前にこれを阻止することができました。

攻撃者の行動を続けさせていた場合、彼らはこの組織やその顧客の知的財産(IP)や機密性の財務データにアクセスすることができていたでしょう。これらの情報は将来、企業に何万ドルもの被害を及ぼすことが知られている、偽の支払い要求のための武器として使われていたかもしれません。

Cyber AI Analystによる脅威の調査

数百名のエキスパートサイバーアナリストによりトレーニングされたCyber AI AnalystはSaaSアカウント侵害を含めたあらゆる種類の脅威に対して自律的な調査を実施します。このケースでは、異常なログインとユーザーの動作をつなぎ合わせ、レビューに使用できるインシデントについての自然言語で書かれたサマリーを生成しました。人間のアナリストであれば、これを作成するのに平均で3時間程度かかると思われます。Cyber AI Analyst はこれをほんの数秒で行い、92%の時間節約を実現しています。

図3:Cyber AI Analystによる不審なログインとファイルアクセスについてのレポート例

まとめの考察

ダイナミックなワークフォースの分散はこれまで以上に進み、SaaSアプリケーションや広範囲に広がったITシステム上で貴重なデータがホスティングされています。今日のデジタルにグローバル化した世界においては、サイバーセキュリティもユビキタスであることが求められ、デジタル環境全体に完全な可視性を持たなければなりません。

このサイバー攻撃は標的型で巧妙なものでした。漏えいした認証情報が使用されたため、ログイン成功前にブルートフォースアクティビティは見られませんでした。さらに、攻撃者は2要素認証を突破し、またEメールの削除によって痕跡を消して正当なユーザーアクティビティに溶け込もうとしました。

DarktraceのAI は、上記にも関わらずユーザーの挙動のかすかな異常を検知し、環境内に望ましくない存在があることを特定したのです。DarktraceはクラウドやSaaS内の攻撃ライフサイクル全体をカバーすることができ、最初のスピアフィッシングメールから完全なアカウント乗っ取りまで、他のセキュリティ対策、たとえば2FAが侵害された場合でも検知可能です。これらの攻撃においては、早期検知と早期対応が鍵です。Darktraceが攻撃を検知していなければ、著しい金銭的および評判上の悪影響があったと思われます。

この調査結果についての考察はDarktraceアナリストBrianna Leddy が協力しました。

INSIDE THE SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
AUTHOR
ABOUT ThE AUTHOR
Max Heinemeyer
Chief Product Officer

Max is a cyber security expert with over a decade of experience in the field, specializing in a wide range of areas such as Penetration Testing, Red-Teaming, SIEM and SOC consulting and hunting Advanced Persistent Threat (APT) groups. At Darktrace, Max is closely involved with Darktrace’s strategic customers & prospects. He works with the R&D team at Darktrace, shaping research into new AI innovations and their various defensive and offensive applications. Max’s insights are regularly featured in international media outlets such as the BBC, Forbes and WIRED. Max holds an MSc from the University of Duisburg-Essen and a BSc from the Cooperative State University Stuttgart in International Business Information Systems.

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Looking Beyond Secure Email Gateways with the Latest Innovations to Darktrace/Email

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09
Apr 2024

Organizations Should Demand More from their Email Security

In response to a more intricate threat landscape, organizations should view email security as a critical component of their defense-in-depth strategy, rather than defending the inbox alone with a traditional Secure Email Gateway (SEG). Organizations need more than a traditional gateway – that doubles, instead of replaces, the capabilities provided by native security vendor – and require an equally granular degree of analysis across all messaging, including inbound, outbound, and lateral mail, plus Teams messages.  

Darktrace/Email is the industry’s most advanced cloud email security, powered by Self-Learning AI. It combines AI techniques to exceed the accuracy and efficiency of leading security solutions, and is the only security built to elevate, not duplicate, native email security.  

With its largest update ever, Darktrace/Email introduces the following innovations, finally allowing security teams to look beyond secure email gateways with autonomous AI:

  • AI-augmented data loss prevention to stop the entire spectrum of outbound mail threats
  • an easy way to deploy DMARC quickly with AI
  • major enhancements to streamline SOC workflows and increase the detection of sophisticated phishing links
  • expansion of Darktrace’s leading AI prevention to lateral mail, account compromise and Microsoft Teams

What’s New with Darktrace/Email  

Data Loss Prevention  

Block the entire spectrum of outbound mail threats with advanced data loss prevention that builds on tags in native email to stop unknown, accidental, and malicious data loss

Darktrace understands normal at individual user, group and organization level with a proven AI that detects abnormal user behavior and dynamic content changes. Using this understanding, Darktrace/Email actions outbound emails to stop unknown, accidental and malicious data loss.  

Traditional DLP solutions only take into account classified data, which relies on the manual input of labelling each data piece, or creating rules to catch pattern matches that try to stop data of certain types leaving the organization. But in today’s world of constantly changing data, regular expression and fingerprinting detection are no longer enough.

  • Human error – Because it understands normal for every user, Darktrace/Email can recognize cases of misdirected emails. Even if the data is correctly labelled or insensitive, Darktrace recognizes when the context in which it is being sent could be a case of data loss and warns the user.  
  • Unclassified data – Whereas traditional DLP solutions can only take action on classified data, Darktrace analyzes the range of data that is either pending labels or can’t be labeled with typical capabilities due to its understanding of the content and context of every email.  
  • Insider threat – If a malicious actor has compromised an account, data exfiltration may still be attempted on encrypted, intellectual property, or other forms of unlabelled data to avoid detection. Darktrace analyses user behaviour to catch cases of unusual data exfiltration from individual accounts.

And classification efforts already in place aren’t wasted – Darktrace/Email extends Microsoft Purview policies and sensitivity labels to avoid duplicate workflows for the security team, combining the best of both approaches to ensure organizations maintain control and visibility over their data.

End User and Security Workflows

Achieve more than 60% improvement in the quality of end-user phishing reports and detection of sophisticated malicious weblinks1

Darktrace/Email improves end-user reporting from the ground up to save security team resource. Employees will always be on the front line of email security – while other solutions assume that end-user reporting is automatically of poor quality, Darktrace prioritizes improving users’ security awareness to increase the quality of end-user reporting from day one.  

Users are empowered to assess and report suspicious activity with contextual banners and Cyber AI Analyst generated narratives for potentially suspicious emails, resulting in 60% fewer benign emails reported.  

Out of the higher-quality emails that end up being reported, the next step is to reduce the amount of emails that reach the SOC. Darktrace/Email’s Mailbox Security Assistant automates their triage with secondary analysis combining additional behavioral signals – using x20 more metrics than previously – with advanced link analysis to detect 70% more sophisticated malicious phishing links.2 This directly alleviates the burden of manual triage for security analysts.

For the emails that are received by the SOC, Darktrace/Email uses automation to reduce time spent investigating per incident. With live inbox view, security teams gain access to a centralized platform that combines intuitive search capabilities, Cyber AI Analyst reports, and mobile application access. Analysts can take remediation actions from within Darktrace/Email, eliminating console hopping and accelerating incident response.

Darktrace takes a user-focused and business-centric approach to email security, in contrast to the attack-centric rules and signatures approach of secure email gateways

Microsoft Teams

Detect threats within your Teams environment such as account compromise, phishing, malware and data loss

Around 83% of Fortune 500 companies rely on Microsoft Office products and services, particularly Teams and SharePoint.3

Darktrace now leverages the same behavioral AI techniques for Microsoft customers across 365 and Teams, allowing organizations to detect threats and signals of account compromise within their Teams environment including social engineering, malware and data loss.  

The primary use case for Microsoft Teams protection is as a potential entry vector. While messaging has traditionally been internal only, as organizations open up it is becoming an entry vector which needs to be treated with the same level of caution as email. That’s why we’re bringing our proven AI approach to Microsoft Teams, that understands the user behind the message.  

Anomalous messaging behavior is also a highly relevant indicator of whether a user has been compromised. Unlike other solutions that analyze Microsoft Teams content which focus on payloads, Darktrace goes beyond basic link and sandbox analysis and looks at actual user behavior from both a content and context perspective. This linguistic understanding isn’t bound by the requirement to match a signature to a malicious payload, rather it looks at the context in which the message has been delivered. From this analysis, Darktrace can spot the early symptoms of account compromise such as early-stage social engineering before a payload is delivered.

Lateral Mail Analysis

Detect and respond to internal mailflow with multi-layered AI to prevent account takeover, lateral phishing and data leaks

The industry’s most robust account takeover protection now prevents lateral mail account compromise. Darktrace has always looked at internal mail to inform inbound and outbound decisions, but will now elevate suspicious lateral mail behaviour using the same AI techniques for inbound, outbound and Teams analysis.

Darktrace integrates signals from across the entire mailflow and communication patterns to determine symptoms of account compromise, now including lateral mailflow

Unlike other solutions which only analyze payloads, Darktrace analyzes a whole range of signals to catch lateral movement before a payload is delivered. Contributing yet another layer to the AI behavioral profile for each user, security teams can now use signals from lateral mail to spot the early symptoms of account takeover and take autonomous actions to prevent further compromise.

DMARC

Gain in-depth visibility and control of 3rd parties using your domain with an industry-first AI-assisted DMARC

Darktrace has created the easiest path to brand protection and compliance with the new Darktrace/DMARC. This new capability continuously stops spoofing and phishing from the enterprise domain, while automatically enhancing email security and reducing the attack surface.

Darktrace/DMARC helps to upskill businesses by providing step by step guidance and automated record suggestions provide a clear, efficient road to enforcement. It allows organizations to quickly achieve compliance with requirements from Google, Yahoo, and others, to ensure that their emails are reaching mailboxes.  

Meanwhile, Darktrace/DMARC helps to reduce the overall attack surface by providing visibility over shadow-IT and third-party vendors sending on behalf of an organization’s brand, while informing recipients when emails from their domains are sent from un-authenticated DMARC source.

Darktrace/DMARC integrates with the wider Darktrace product platform, sharing insights to help further secure your business across Email Attack Path and Attack Surface management.

結論

To learn more about the new innovations to Darktrace/Email download the solution brief here.

All of the new updates to Darktrace/Email sit within the new Darktrace ActiveAI Security Platform, creating a feedback loop between email security and the rest of the digital estate for better protection. Click to read more about the Darktrace ActiveAI Security Platform or to hear about the latest innovations to Darktrace/OT, the most comprehensive prevention, detection, and response solution purpose built for critical infrastructures.  

Learn about the intersection of cyber and AI by downloading the State of AI Cyber Security 2024 report to discover global findings that may surprise you, insights from security leaders, and recommendations for addressing today’s top challenges that you may face, too.

参考文献

[1] Internal Darktrace Research

[2] Internal Darktrace Research

[3] Essential Microsoft Office Statistics in 2024

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Carlos Gray
Product Manager

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Managing Risk Beyond CVE Scores With the Latest Innovations to Darktrace/OT

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09
Apr 2024

Identifying Cyber Risk in Industrial Organizations

Compromised OT devices in ICS and SCADA environments pose significant physical risks, even endangering lives. However, identifying CVEs in the multitude of complex OT devices is labor-intensive and time-consuming, draining valuable resources.

Even after identifying a vulnerability, implementing a patch presents its own challenges limited maintenance windows and the need for uninterrupted operations strain IT and OT teams often leading organizations to prioritize availability over security leading vulnerabilities remaining unresolved for over 5 years on average. (1)

Darktrace’s New Innovation

Darktrace is an industry leader in cybersecurity with 10+ years of experience securing OT environments where we take a fundamentally different approach using Self-Learning AI to enhance threat detection and response.

Continuing to combat the expanding threat landscape, Darktrace is excited to announce new capabilities that enable a contextualized and proactive approach to managing cyber risk at industrial organizations.

Today we launch an innovation to our OT Cybersecurity solution, Darktrace/OT, that will add a layer of proactivity, enabling a comprehensive approach to risk management. This industry leading innovation for Darktrace/OT moves beyond CVE scores to redefine vulnerability management for critical infrastructure, tackling the full breadth of risks not limited by traditional controls.  

Darktrace/OT is the only OT security solution with comprehensive Risk Management which includes:

  • Contextualized risk analysis unique to your organization
  • The most realistic evaluation and prioritization of OT risk
  • Effectively mitigate risk across your OT infrastructure, with and without patching.
  • The only OT security solution that evaluates your defenses against Advanced Persistent Threat (APT) Groups.

The most comprehensive prevention, detection, and response solution purpose built for Critical Infrastructures

Darktrace’s Self-Learning AI technology is a cutting-edge innovation that implements real time prevention, detection, response, and recovery for operational technologies and enables a fundamental shift from the traditional approach to cyber defense by learning a ‘pattern of life’ for every network, device, and user.  

Rather than relying on knowledge of past attacks, AI technology learns what is ‘normal’ for its environment, discovering previously unknown threats by detecting subtle shifts in behavior. Through identifying these unexpected anomalies, security teams can investigate novel attacks, discover blind spots, have live time visibility across all their physical and digital assets, and reduce time to detect, respond to, and triage security events.  

  • Achieve greater visibility of OT and IT devices across all levels of the Purdue Model.
  • The industry's only OT security to scale threat detection and response, with a 92% time saving from triage to recovery.  
  • The only OT focused security solution to provide bespoke Risk Management.

To learn more about how Darktrace/OT approaches unique use cases for industrial organizations visit the Darktrace/OT Webpage or join us LIVE at a city near you.

Read more below to discover how new innovations to Darktrace/OT are bringing a new, contextualized approach to Risk Management for Industrial organizations.

For more information on the entire Darktrace/OT Solution read our solution brief here.

Darktrace/OT and New Risk Management

Risk Identification

Leveraging the visibility of Darktrace/OT which identifies individual systems throughout the Purdue Model and the relationship between them, Darktrace/OT identifies high-risk CVEs and presents potential attack routes that go beyond techniques requiring a known exploit, such as misuse of legitimate services. Each attack path will have a mathematical evaluation of difficulty and impact from initial access to the high value objectives.  

Together this gives comprehensive coverage over your real and potential risks from both an attacker and known vulnerability perspectives. OT attack paths as seen here even leverage insights between the industrial and corporate communications to reveal ways threat actors may take advantage of IT-OT convergence. This revelation of imperceptible risks fills gaps in traditional risk analysis like remote access and insider threats.

Figure 1: Darktrace/OT visualizing the most critical attack paths at an organization
Figure 1: Darktrace/OT visualizing the most critical attack paths at an organization
Figure 2: A specific Attack Path identified by Darktrace/OT

Risk Prioritization

Darktrace/OT prioritizes remediations and mitigations based on difficulty and damage to your unique organization, using the established Attack Paths.

We ascertain the priorities that apply to your organization beyond pure theoretical damage answering questions like:

  • How difficult is a particular vulnerability to exploit considering the steps an attacker would require to reach it?
  • And, how significant would the impact be if it was exploited within this particular network?

This expanded approach to risk prioritization has a much more comprehensive evaluation of your organization's unique risk than has ever been possible before. Traditional approaches of ranking only known vulnerabilities with isolated scores using CVSS and exploitability metrics, often leaves gaps in IT-OT risks and is blind to legitimate service exploitation.

Figure 3: Darktrace/OT leverages its contextual understand of the organization’s network to prioritize remediation that will have the positive impact on the risk score

Darktrace provides mitigation strategies associated with each identified risk and the relevant impact it has on your overall risk posture, across all MITRE ATT&CK techniques.

What sets Darktrace apart is our ability to contextualize these mitigations within the broader business. When patching vulnerabilities directly isn’t possible, Darktrace identifies alternative actions that harden attack paths leading to critical assets. Hardening the surrounding attack path increases the difficulty and therefore reduces the likelihood and impact of a breach.

That means unpatched vulnerabilities and vulnerable devices aren’t left unprotected. This also has an added bonus, those hardening techniques work for all devices in that network segment, so apply one change, secure many.

Figure 4: Darktrace prioritizes mitigation reducing accessibility of vulnerability and the overall risk score when patches aren’t available

Communicate Board Level Risk with APT Threat Mapping

Darktrace/OT bridges theory and practice as the only security solution that maps MITRE techniques, frequently used by APT Groups, onto AI-assessed critical Attack Paths. This unique solution provides unparalleled insights including sector and location intelligence, possible operating platforms, common techniques, exploited CVEs, and the number of potential devices affected in your environment, supporting holistic risk assessment and proactive defense measures.

Ultimately, this becomes a power dashboard to communicate board level risk, using both metric based evidence and industry standard threat mapping.

結論

Darktrace/OT is part of the Darktrace ActiveAI Security Platform a native, holistic, AI-driven platform built on over ten years of AI research. It helps security teams shift to more a productive mode, finding the known and the unknown attacks and transforming the SOC with the various Darktrace products to drive efficiency gains. It does this across the whole incident lifecycle to lower risk, reduce time spent on active incidents, and drive return on investment.

Discover more about Darktrace's ever-strengthening platform with the upcoming changes coming to our Darktrace/Email product and other launch day blogs.

Join Darktrace LIVE half-day event to understand the reality versus the hype surrounding AI and how to achieve cyber resilience.

Learn about the intersection of cyber and AI by downloading the State of AI Cyber Security 2024 report to discover global findings that may surprise you, insights from security leaders, and recommendations for addressing today’s top challenges that you may face, too.  

参考文献

1. https://research-information.bris.ac.uk/ws/portalfiles/portal/313646831/Catch_Me_if_You_Can.pdf

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Mitchell Bezzina
VP, Product and Solutions Marketing
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