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多様な言語によるフィッシング攻撃を阻止する

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16
Jun 2021
16
Jun 2021
With globalized companies and supply chains, organizations need one solution which works for all emails no matter the time zone, no matter the language. This blog analyses how Antigena Email stopped a series of multi-language phishing attacks, including an Emotet campaign in Japanese.

Click here! Clique aqui! ここをクリック! Klikk here! !اینجا کلیک کنید naDev yIbej! Hic tange!

言葉は人を惑わせます。Eメールセキュリティの領域では、言葉により受信者にリンクをクリックさせたり取引を完了させたりできます。また、セキュリティツールを騙して、Eメールが正当なものであると思わせることもできます。

このような理由から、Darktrace/Emailは言語に依存せず、数学を用いて、組織内のすべてのEメールユーザーの「通常の状態」への理解を構築します。これにより、書式や言語にかかわらず、脅威を示す世界中のEメールを無力化することができます。

自然言語処理

侵害されたアカウントやなりすましEメールを捕捉する際に、人間による普通の対応と比較した、意図やトーンの違いをどのようにコンピューターに教えることができるでしょうか。

Eメールセキュリティにおいて最も一般的なアプローチの1つが、自然言語処理(NLP)です。NLPでは、自然言語(人間の言葉)を分析する方法についてコンピューターをどうプログラミングするかが焦点となります。一般的には、大量のデータに晒すことによって行います。

その結果、文書の内容を、言葉のニュアンスを含めて「理解」できるコンピューターができあがります。その後、このテクノロジーを用いて、文書内の情報を抽出するとともに、文書自体を分類整理することができます。

現代における制約

しかし、Eメールセキュリティ分野におけるNLPの利用は限定されています。これは、専門用語や口語、さらにはプログラミング当時にはなかった用語などについてもさらに教育をしない限り、理解を誤ってしまうためです。また、言語を追加するたびに、毎回ゼロからの学習が必要になります。NLPは、学習した言語に対してのみ機能するため、すべての小規模市場で機能するように教育するには採算が合いません。

したがって、米国に本社を置くEメールセキュリティベンダーの製品を採用した場合、そのベンダーは英語ベースのフィッシングの脅威を検知するために大半の時間を割いている可能性が高くなります。英語でのみやりとりしているなら問題ありませんが、そうではない場合も少なくありません。グローバル化された21世紀の世界では、言語に依存しないセキュリティテクノロジーのニーズはこれまでになく高まっています。

AIはどれでも同じではない: 教師なし機械学習

Darktrace Emailは教師なし機械学習を使用しています。この技術は「オンザジョブ」で学習することができ、大量のデータセットを入力する必要がありません。NLPからの考察を追加情報として得ることはできますが、検知や理解はNLPに依存しません。

AIを使用する際には、オンザジョブで学習しているのか、ラベル付きデータセットで学習しているのか、AIの学習方法に対する理解が不可欠です。これは、なりすまし、フィッシング、サプライヤー偽装、その他あらゆる形式のメール攻撃によってユーザーをそそのかす試みを暴くために、Eメールに潜む意図を理解しようとする場合には特に重要です。

Darktrace Cyber AIは、Eメールの中の言語を理解するようにコンピューターを教育する代わりに、送受信されるEメールについての送信者、受信者、リンク、IPアドレス、添付アドレスの種類などのアクティビティを動的に評価します。次にAIは、これらすべてのオブジェクトの動きを利用して、すべてのやりとりにわたってすべてのユーザーの「生活パターン」を作成します。これには、ビジネスでの外部ユーザーとの頻繁なやりとりも含まれます。

数学的なアプローチを採ることで、Darktrace Emailはやりとりに使用する専門用語や方言にかかわらず「通常の状態」を理解し、ノルウェー語からラテン語、ペルシャ語に至るまであらゆる言語を独自に解釈し、その結果フィッシング攻撃やアカウント乗っ取りを示すわずかな異常を識別します。

日本語のEmotetを捕捉する

昨年、Darktraceは、悪名高いバンキングマルウェアであるEmotetを利用した高度なスパムウェア攻撃を発見しました。この攻撃はさまざまな業界を標的として、きわめて高度なフィッシングメールを使用していました。

日本のある食品企業で、Darktraceは7月の2日間に6件のフィッシングメールを検知しました。

図1:EmotetによるEメール

上のメールでは、件名行とファイル名の両方に「請求書の件」と書かれ、その後に数字と日付が続いています。ここで攻撃者は明らかに、正当な業務メールを模倣しようと試み、有名な日本企業(三菱食品(株))と、一般的な日本語の氏名を(藤沢 昭彦)を用いています。

Darktrace/Emailはこのメールの背後にある主な特徴を明らかにしました。真の送信者はGMO(安価なウェブメールサービスを提供する日本企業)のドメイン名を使用し、実は日本ではなくポルトガルに所在していました。

図2:Antigena Emailが勧誘の試みを検知

Darktrace/Emailのモデルは、Eメールが書かれている言語にかかわらず、トピックの異常性と、Eメールにおけるそそのかしの試みを認識し、85点という高い異常スコアを与えました。さらに、DarktraceのAIは、添付ファイルの拡張子とMIMEタイプも、このユーザーが通常Eメールでやりとりする場合と比較して異常であると判定しました。

ポルトガル語による脅威の発見

別のインスタンスでは、欧州にある企業に、悪意のある一連のEメールが送信されました。これらのEメールは、件名行のパーソナライズや悪意あるURLの隠蔽など、企業のセキュリティツールを回避するために複数の戦術を用いていました。

図3:Darktrace/Emailの対話型ユーザーインターフェイス。件名には「送金通知」と書かれています。

このEメールはCaixaBankドメインにつながっているように見えるリンクが含まれていました。しかし、Darktrace Emailはこれを、受信者を誤解させる故意の試みと認識しました。実際に、リンク先はあるWordPressドメインで、このドメインはCyber AIによって、同社にとって100%稀であると識別されました。

さらに詳しく調べたところ、これらのEメールはベトナムから送信されたことがわかりました。この送信者は同社と過去にやりとりしたことがなく、Eメール内の孤立したリンクも、100%稀なドメインとしてマークされていました。Darktrace Emailはこれらの悪意あるEメールを保留し、企業を被害から未然に保護しました。

世界共通の防衛

この2つの例は、教師なし機械学習アプローチのメリットを示しています。既存のデータに頼らず数百種類におよぶ指標を分析するAIセキュリティソリューションは、幅広い言語を利用するようになっているグローバルなフィッシング脅威に対して圧倒的な優位性があります。

Eメールベースの攻撃は、日増しに標的を絞り、説得力を高めています。高度な翻訳ツールを用いた、標的を絞ったソーシャルエンジニアリングとスピアフィッシングは、毎日のように企業にあらゆる言語で集中攻撃を浴びせています。

韓国の現地事務所を対象にしたフィッシング攻撃でも、アラビア語によるそそのかしの試みでも、あるいは『スタートレック』コンベンションから送信されたクリンゴン語(同シリーズに登場する架空の言語)の悪意あるメールでさえも、さらには無数の方言やトーンで行われるどんなメールのやりとりでも、Darktrace Emailは世界中、そしてさらに広い範囲で、顧客の企業を保護します。

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
Mariana Pereira
VP, Cyber Innovation

Mariana is the VP of Cyber Innovation at Darktrace, and works closely with the development, analyst, and marketing teams to advise technical and non-technical audiences on how best to augment cyber resilience, and how to implement AI technology as a means of defense. She speaks regularly at international events, with a specialism in presenting on sophisticated, AI-powered email attacks. She holds an MBA from the University of Chicago, and speaks several languages including French, Italian, and Portuguese.

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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
Our ai. Your data.

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