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July 16, 2025

サイバーセキュリティのためのAI成熟度モデルの紹介

サイバーセキュリティのためのAI成熟度モデルは、実際のユースケースとエキスパートの知見に基づいた、この種の指針の中でも最も詳細なガイドです。CISOが戦略的な意思決定を行うための力となり、どのAIを導入すべきかだけではなく、組織を段階的に強化し優れた成果を得るためにどのように進めるべきかを知ることができます。
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.
Written by
Ashanka Iddya
Senior Director, Product Marketing
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16
Jul 2025

サイバーセキュリティへのAIの導入:宣伝文句を超えて

今日のセキュリティオペレーションはパラドックスに直面しています。業界ではAI(Artificial Intelligence)が全面的な変革を約束し、ルーチンタスクを自動化することにより検知と対処が強化されると言われています。しかしその一方で、セキュリティリーダーは意味のあるイノベーションとベンダーの宣伝文句を区別しなければならないという大きなプレッシャーに直面しています。

CISOとセキュリティチームがこの状況を乗り越えるのを支援するため、私たちは業界で最も詳細、かつアクション可能なAI成熟度モデルを作成しました。AIおよびサイバーセキュリティ分野のエキスパートと協力して作成したこの枠組みは、セキュリティライフサイクル全体を通じてAIの導入を理解し、測定し、進めていくためのしっかりとした道筋を提供します。

なぜ成熟度モデル?なぜ今必要?

セキュリティリーダー達との対話と調査の中で繰り返し浮かび上がってきたテーマがあります。

それは、AIソリューションはまったく不足していないが、AIのユースケースの明瞭性と理解が不足している、ということです。

事実、Gartner社は「2027年までに、エージェント型AIプロジェクトの40%以上が、コスト上昇、不明瞭なビジネス上の価値、あるいは不十分なリスク制御を理由として打ち切られるだろう」と予測しています。多くのセキュリティチームが実験を行っていますが、その多くは意味のある成果を得られていません。セキュリティの向上を評価し情報に基づいた投資を行うための、標準化された方法に対する必要性はかつてなく高まっています。

AI成熟度モデルが作成されたのはこのような背景によるものであり、これは次を行うための戦略的枠組みです:

  • 人手によるプロセス(L0)からAIへの委任(L4)に至る5段階の明確なAI成熟度を定義
  • エージェント型生成AIと専用AIエージェントシステムから得られる結果を区別
  • リスク管理、脅威検知、アラートトリアージ、インシデント対応といった中核的な機能にわたって評価
  • AI成熟度を、リスクの削減、効率の向上、スケーラブルなオペレーションなど、現実の成果に対応させる

[related-resource]

このモデルで成熟度はどのように評価されるか?

「サイバーセキュリティにおけるAI成熟度モデル」は、世界で10,000社に及ぶDarktraceの自己学習型AIおよびCyber AI Analystの導入例から得られたセキュリティオペレーションの知見に基づいています。抽象的な理論やベンダーのベンチマークに頼るのではなく、このモデルは実際にセキュリティチームが直面している課題に基づき、AIがどこに導入されているか、どのように使用されているか、そしてどのような成果をもたらしているかを反映しています。

こうした現実に即した基盤により、このモデルはAI成熟度に対する実務的な、体験に基づいた視点を提供します。セキュリティチームが現在の状態を把握し、同じような組織がどのように進化しているかに基づいて現実的な次のステップを知るのに役立ちます。

Darktraceを選ぶ理由

AIは2013年のダークトレースの設立以来そのミッションの中心であり、単なる機能ではなく、企業の基盤です。10年以上にわたりAIを開発し現実のセキュリティ環境にAIを適用してきた経験から、私たちはAIがどこに有効で、どこに有効でないか、そしてAIから最も大きな価値を得るにはどうすべきかを学びました。

私たちは、現代のビジネスが膨大な、相互に接続されたエコシステム内で動いていること、そしてそこには従来のサイバーセキュリティアプローチの維持を不可能にする新たな複雑さや脆弱さが生まれていることを知っています。多くのベンダーは機械学習を使用していますが、AIツールはそれぞれ異なり、どれも同じように作られているわけではありません。

Darktraceの自己学習型AIは多層的なAIアプローチを使用して、それぞれの組織から学習することにより、現代の高度な脅威に対するプロアクティブかつリジリエントな防御を提供します。機械学習、深層学習、LLM、自然言語処理を含む多様なAIテクニックを戦略的に組み合わせ、連続的、階層的に統合することにより、私たちの多層的AIアプローチはそれぞれの組織専用の、変化する脅威ランドスケープに適応する強力な防御メカニズムを提供します。

この成熟度モデルはこうした知見を反映し、セキュリティリーダーが組織の人、プロセス、ツールに適した適切な道筋を見つけるのに役立ちます。

今日のセキュリティチームは次のような重要な問いに直面しています:

  • AIを具体的に何のために使うべきか?
  • 他のチームはどのように使っているのか?そして何が機能しているのか?
  • ベンダーはどのようなツールを提供しているのか、そして何が単なる宣伝文句なのか?
  • AIはSOCの人員を置き換える可能性があるのか?

これらはもっともな質問ですが、簡単に答えられるとは限りません。それが、私たちがこのモデルを作成した理由です。セキュリティリーダーが単なるバズワードに惑わされず、SOC全体にAIを適用するための明確かつ現実的な計画を作成するのを助けるために、このモデルが作成されました。

構成:実験から自律性まで

このモデルは5つの成熟段階で構成されています:

L0 –  人手によるオペレーション:プロセスはほとんどが人手によるものであり、一部のタスクにのみ限定的な自動化が使用されます。

L1 –  自動化ルール:人手により管理されるか、外部ソースからの自動化ルールとロジックが可能な範囲で使用されます。    

L2 –  AIによる支援:AIは調査を支援するが、良い判断をするかどうかは信頼されていません。これには人手によるエラーの監視が必要な生成AIエージェントが含まれます。    

L3 –  AIコラボレーション:組織のテクノロジーコンテキストを理解した専用のサイバーセキュリティAIエージェントシステムに特定のタスクと判断を任せます。生成AIはエラーが許容可能な部分に使用が限定されます。  

L4 –  AIに委任:組織のオペレーションと影響について格段に幅広いコンテキストを備えた専用のAIエージェントがほとんどのサイバーセキュリティタスクと判断を単独で行い、ハイレベルの監督しか必要としません。

それぞれの段階が、テクノロジーだけではなく、人とプロセスもシフトすることを表しています。AIが成熟するにつれ、アナリストの役割は実行者から戦略的監督者へと進化します。

セキュリティリーダーにとっての戦略上の利益

成熟度モデルの目的はテクノロジーの導入だけではなく、AIへの投資を測定可能なオペレーションの成果に結びつけることです。AIによって次のことが可能になります:

SOCの疲労は切実、AIが軽減に貢献

ほとんどのセキュリティチームは現在もアラートの量、調査の遅延、受け身のプロセスに苦労しています。しかしAIの導入には一貫性がなく、多くの場合サイロ化しています。上手く統合すれば、AIはセキュリティチームの効率を高めるための、意味のある違いをもたらすことができます。

生成AIはエラーが起こりやすく、人間による厳密な監視が必要

生成AIを使ったエージェント型システムについては多くの誇大広告が見られますが、セキュリティチームはエージェント型生成AIシステムの不正確性とハルシネーションの可能性についても考慮に入れる必要があります。

AIの本当の価値はセキュリティの進化にある

AI導入の最も大きな成果は、リスク対策から検知、封じ込め、修復に至るまで、セキュリティライフサイクル全体にAIを統合することから得られます。

AIへの信頼と監督は初期段階で必須となるが次第に変化する

導入の初期段階では、人間が完全にコントロールします。L3からL4に到達する頃には、AIシステムは決められた境界内で独立して機能するようになり、人間の役割は戦略的監督になります。

人間の役割が意味のあるものに変化する

AIが成熟すると、アナリストの役割は労働集約的な作業から高価値な意思決定へと引き上げられ、重要な、ビジネスへの影響が大きいアクティビティやプロセスの改良、AIに対するガバナンスなどに集中できるようになります。

成熟度を定義するのは宣伝文句ではなく成果

AIの成熟度は単にテクノロジーが存在しているかどうかではなく、リスク削減、対処時間、オペレーションのリジリエンスに対して測定可能な効果が見られるかどうかで決まります。

[related-resource]

AI成熟度モデルの各段階の成果

セキュリティ組織は人手によるオペレーションからAIへの委任へと進むにつれてサイバーセキュリティの進化を体験するでしょう。成熟度の各レベルは、効率、精度、戦略的価値の段階的変化を表しています。

L0 – 人手によるオペレーション

この段階では、アナリストが手動でトリアージ、調査、パッチ適用、報告を、基本的な自動化されていないツールを使って行います。その結果、受け身の労働集約的なオペレーションになり、ほとんどのアラートは未調査のままとなり、リスク管理にも一貫性がありません。

L1 – 自動化ルール

この段階では、アナリストがSOARあるいはXDRといったルールベースの自動化ツールを管理します。これにより多少の効率化は図れますが、頻繁な調整を必要とします。オペレーションは依然として人員数と事前に定義されたワークフローに制限されます。

L2 – AIによる支援

この段階では、AIが調査、まとめ、トリアージを支援し、アナリストの作業負荷を軽減しますが、エラーの可能性もあるためきめ細かな監督が必要です。検知は向上しますが、自律的な意思決定に対する信頼度は限定的です。

L3 – AIコラボレーション

この段階では、AIが調査全体を行いアクションを提示します。アナリストは高リスクの判断を行うことと、検知戦略の精緻化に集中します。組織のテクノロジーコンテキストを考慮した専用のエージェント型AIエージェントシステムに特定のタスクが任され、精度と優先度の判断が向上します。

L4 – AIに委任

この段階では、専用のAIエージェントシステムが単独でほとんどのセキュリティタスクをマシンスピードで処理し、人間のチームはハイレベルの戦略的監督を行います。このことは、人間のセキュリティチームが最も時間と労力を使うアクティビティはプロアクティブな活動に向けられ、AIがルーチンのサイバーセキュリティ作業を処理することを意味します。

専用のAIエージェントシステムはビジネスへの影響を含めた深いコンテキストを理解して動作し、高速かつ効果的な判断を行います。

AI成熟度モデルのどこに位置しているかを調べる

「サイバーセキュリティのためのAI成熟度モデル」 ホワイトペーパーを入手し、評価を行ってみましょう。自社の現在の成熟段階をベンチマークし、主なギャップがどこにあるのかを調べ、次のステップの優先順位を特定するためににお役立てください。

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.
Written by
Ashanka Iddya
Senior Director, Product Marketing

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May 5, 2026

When Trust Becomes the Attack Surface: Supply-Chain Attacks in an Era of Automation and Implicit Trust

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Software supply-chain attacks in 2026

Software supply-chain attacks now represent the primary threat shaping the 2026 security landscape. Rather than relying on exploits at the perimeter, attackers are targeting the connective tissue of modern engineering environments: package managers, CI/CD automation, developer systems, and even the security tools organizations inherently trust.

These incidents are not isolated cases of poisoned code. They reflect a structural shift toward abusing trusted automation and identity at ecosystem scale, where compromise propagates through systems designed for speed, not scrutiny. Ephemeral build runners, regardless of provider, represent high‑trust, low‑visibility execution zones.

The Axios compromise and the cascading Trivy campaign illustrate how quickly this abuse can move once attacker activity enters build and delivery workflows. This blog provides an overview of the latest supply chain and security tool incidents with Darktrace telemetry and defensive actions to improve organizations defensive cyber posture.

1. Why the Axios Compromise Scaled

On 31 March 2026, attackers hijacked the npm account of Axios’s lead maintainer, publishing malicious versions 1.14.1 and 0.30.4 that silently pulled in a malicious dependency, plain‑crypto‑[email protected]. Axios is a popular HTTP client for node.js and  processes 100 million weekly downloads and appears in around 80% of cloud and application environments, making this a high‑leverage breach [1].

The attack chain was simple yet effective:

  • A compromised maintainer account enabled legitimate‑looking malicious releases.
  • The poisoned dependency executed Remote Access Trojans (RATs) across Linux, macOS and Windows systems.
  • The malware beaconed to a remote command-and-control (C2) server every 60 seconds in a loop, awaiting further instructions.
  • The installer self‑cleaned by deleting malicious artifacts.

All of this matters because a single maintainer compromise was enough to project attacker access into thousands of trusted production environments without exploiting a single vulnerability.

A view from Darktrace

Multiple cases linked with the Axios compromise were identified across Darktrace’s customer base in March 2026, across both Darktrace / NETWORK and Darktrace / CLOUD deployments.

In one Darktrace / CLOUD deployment, an Azure Cloud Asset was observed establishing new external HTTP connectivity to the IP 142.11.206[.]73 on port 8000. Darktrace deemed this activity as highly anomalous for the device based on several factors, including the rarity of the endpoint across the network and the unusual combination of protocol and port for this asset. As a result, the triggering the "Anomalous Connection / Application Protocol on Uncommon Port" model was triggered in Darktrace / CLOUD. Detection was driven by environmental context rather than a known indicator at the time. Subsequent reporting later classified the destination as malicious in relation to the Axios supply‑chain compromise, reinforcing the gap that often exists between initial attacker activity and the availability of actionable intelligence. [5]

Additionally, shortly before this C2 connection, the device was observed communicating with various endpoints associated with the NPM package manager, further reinforcing the association with this attack.

Darktrace’s detection of the unusual external connection to 142.11[.]206[.]73 via port 8000.  
Figure 1: Darktrace’s detection of the unusual external connection to 142.11[.]206[.]73 via port 8000.  

Within Axios cases observed within Darktrace / NETWORK customer environments, activity generally focused on the use of newly observed cURL user agents in outbound connections to the C2 URL sfrclak[.]com/6202033, alongside the download of malicious files.

In other cases, Darktrace / NETWORK customers with Microsoft Defender for Endpoint integration received alerts flagging newly observed system executables and process launches associated with C2 communication.

A Security Integration Alert from Microsoft Defender for Endpoint associated with the Axios supply chain attack.
Figure 2: A Security Integration Alert from Microsoft Defender for Endpoint associated with the Axios supply chain attack.

2. Why Trivy bypassed security tooling trust

Between late February and March 22, 2026, the threat group TeamPCP leveraged credentials from a previous incident to insert malicious artifacts across Trivy’s distribution ecosystem, including its CI automation, release binaries, Visual Studio Code extensions, and Docker container images [2].

While public reporting has emphasized GitHub Actions, Darktrace telemetry highlights attacker execution within CI/CD runner environments, including ephemeral build runners. These execution contexts are typically granted broad trust and limited visibility, allowing malicious activity within build automation to blend into expected operational workflows, regardless of provider.

This was a coordinated multi‑phase attack:

  • 75 of 76  of trivy-action tags and all setup‑trivy tags were force‑pushed to deliver a malicious payload.
  • A malicious binary (v0.69.4) was distributed across all major distribution channels.
  • Developer machines were compromised, receiving a persistent backdoor and a self-propagating worm.
  • Secrets were exfiltrated at scale, including SSH keys, Kuberenetes tokens, database passwords, and cloud credentials across Amazon Web Service (AWS), Azure, and Google Cloud Platform (GCP).

Within Darktrace’s customer base, an AWS EC2 instance monitored by Darktrace / CLOUD  appeared to have been impacted by the Trivy attack. On March 19, the device was seen connecting to the attacker-controlled C2 server scan[.]aquasecurtiy[.]org (45.148.10[.]212), triggering the model 'Anomalous Server Activity / Outgoing from Server’ in Darktrace / CLOUD.

Despite this limited historical context, Darktrace assessed this activity as suspicious due to the rarity of the destination endpoint across the wider deployment. This resulted in the triggering of a model alert and the generation of a Cyber AI Analyst incident to further analyze and correlate the attack activity.

TeamPCP’s continued abused of GitHub Actions against security and IT tooling has also been observed more recently in Darktrace’s customer base. On April 22, an AWS asset was seen connecting to the C2 endpoint audit.checkmarx[.]cx (94.154.172[.]43). The timing of this activity suggests a potential link to a malicious Bitwarden package distributed by the threat actor, which was only available for a short timeframe on April 22. [4][3]

Figure 3: A model alert flagging unusual external connectivity from the AWS asset, as seen in Darktrace / CLOUD .

While the Trivy activity originated within build automation, the underlying failure mode mirrors later intrusions observed via management tooling. In both cases, attackers leveraged platforms designed for scale and trust to execute actions that blended into normal operational noise until downstream effects became visible.

Quest KACE: Legacy Risk, Real Impact

The Quest KACE System Management Appliance (SMA) incident reinforces that software risk is not confined to development pipelines alone. High‑trust infrastructure and management platforms are increasingly leveraged by adversaries when left unpatched or exposed to the internet.

Throughout March 2026, attackers exploited CVE 2025-32975 to authentication on outdated, internet-facing KACE appliances, gaining administrative control and pushing remote payloads into enterprise environments. Organizations still running pre-patch versions effectively handed adversaries a turnkey foothold, reaffirming a simple strategic truth: legacy management systems are now part of the supply-chain threat surface, and treating them as “low-risk utilities” is no longer defensible [3].

Within the Darktrace customer base, a potential case was identified in mid-March involving an internet-facing server that exhibited the use of a new user agent alongside unusual file downloads and unexpected external connectivity. Darktrace identified the device downloading file downloads from "216.126.225[.]156/x", "216.126.225[.]156/ct.py" and "216.126.225[.]156/n", using the user agents, "curl/8.5.0" & "Python-urllib/3.9".

The timeframe and IoCs observed point towards likely exploitation of CVE‑2025‑32975. As with earlier incidents, the activity became visible through deviations in expected system behavior rather than through advance knowledge of exploitation or attacker infrastructure. The delay between observed exploitation and its addition to the Known Exploited Vulnerabilities (KEV) catalogue underscores a recurring failure: retrospective validation cannot keep pace with adversaries operating at automation speed.

The strategic pattern: Ecosystem‑scale adversaries

The Axios and Trivy compromises are not anomalies; they are signals of a structural shift in the threat landscape. In this post-trust era, the compromise of a single maintainer, repository token, or CI/CD tag can produce large-scale blast radiuses with downstream victims numbering in the thousands. Attackers are no longer just exploiting vulnerabilities; they are exploiting infrastructure privileges, developer trust relationships, and automated build systems that the industry has generally under secured.

Supply‑chain compromise should now be treated as an assumed breach scenario, not a specialized threat class, particularly across build, integration, and management infrastructure. Organizations must operate under the assumption that compromise will occur within trusted software and automation layers, not solely at the network edge or user endpoint. Defenders should therefore expect compromise to emerge from trusted automation layers before it is labelled, validated, or widely understood.

The future of supply‑chain defense lies in continuous behavioral visibility, autonomous detection across developer and build environments, and real‑time anomaly identification.

As AI increasingly shapes software development and security operations, defenders must assume adversaries will also operate with AI in the loop. The defensive edge will come not from predicting specific compromises, but from continuously interrogating behavior across environments humans can no longer feasibly monitor at scale.

Credit to Nathaniel Jones (VP, Security & AI Strategy, FCISCO), Emma Foulger (Global Threat Research Operations Lead), Justin Torres (Senior Cyber Analyst), Tara Gould (Malware Research Lead)

Edited by Ryan Traill (Content Manager)

Appendices

References:

1)         https://www.infosecurity-magazine.com/news/hackers-hijack-axios-npm-package/

2)         https://thehackernews.com/2026/03/trivy-hack-spreads-infostealer-via.html

3)         https://thehackernews.com/2026/03/hackers-exploit-cve-2025-32975-cvss-100.html

4)         https://www.endorlabs.com/learn/shai-hulud-the-third-coming----inside-the-bitwarden-cli-2026-4-0-supply-chain-attack

5)         https://socket.dev/blog/axios-npm-package-compromised?trk=public_post_comment-text

IoCs

- 142.11.206[.]73 – IP Address – Axios supply chain C2

- sfrclak[.]com – Hostname – Axios supply chain C2

- hxxp://sfrclak[.]com:8000/6202033 - URI – Axios supply chain payload

- 45.148.10[.]212 – IP Address – Trivy supply chain C2

- scan.aquasecurtiy[.]org – Hostname - Trivy supply chain C2

- 94.154.172[.]43 – IP Address - Checkmarx/Bitwarden supply chain C2

- audit.checkmarx[.]cx – Hostname - Checkmarx/Bitwarder supply chain C2

- 216.126.225[.]156 – IP Address – Quest KACE exploitation C2

- 216.126.225[.]156/32 - URI – Possible Quest KACE exploitation payload

- 216.126.225[.]156/ct.py - URI - Possible Quest KACE exploitation payload

- 216.126.225[.]156/n - URI - Possible Quest KACE exploitation payload

- 216.126.225[.]156/x - URI - Possible Quest KACE exploitation payload

- e1ec76a0e1f48901566d53828c34b5dc – MD5 - Possible Quest KACE exploitation payload

- d3beab2e2252a13d5689e9911c2b2b2fc3a41086 – SHA1 - Possible Quest KACE exploitation payload

- ab6677fcbbb1ff4a22cc3e7355e1c36768ba30bbf5cce36f4ec7ae99f850e6c5 – SHA256 - Possible Quest KACE exploitation payload

- 83b7a106a5e810a1781e62b278909396 – MD5 - Possible Quest KACE exploitation payload

- deb4b5841eea43cb8c5777ee33ee09bf294a670d – SHA1 - Possible Quest KACE exploitation payload

- b1b2f1e36dcaa36bc587fda1ddc3cbb8e04c3df5f1e3f1341c9d2ec0b0b0ffaf – SHA256 - Possible Quest KACE exploitation payload

Darktrace Model Detections

Anomalous Connection / Application Protocol on Uncommon Port

Anomalous Server Activity / Outgoing from Server

Anomalous Connection / New User Agent to IP Without Hostname

Anomalous File / EXE from Rare External Location

Anomalous File / Script from Rare External Location

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Nathaniel Jones
VP, Security & AI Strategy, Field CISO

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May 5, 2026

How email-delivered prompt injection attacks can target enterprise AI – and why it matters

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What are email-delivered prompt injection attacks?

As organizations rapidly adopt AI assistants to improve productivity, a new class of cyber risk is emerging alongside them: email-delivered AI prompt injection. Unlike traditional attacks that target software vulnerabilities or rely on social engineering, this is the act of embedding malicious or manipulative instructions into content that an AI system will process as part of its normal workflow. Because modern AI tools are designed to ingest and reason over large volumes of data, including emails, documents, and chat histories, they can unintentionally treat hidden attacker-controlled text as legitimate input.  

At Darktrace, our analysis has shown an increase of 90% in the number of customer deployments showing signals associated with potential prompt injection attempts since we began monitoring for this type of activity in late 2025. While it is not always possible to definitively attribute each instance, internal scoring systems designed to identify characteristics consistent with prompt injection have recorded a growing number of high-confidence matches. The upward trend suggests that attackers are actively experimenting with these techniques.

Recent examples of prompt injection attacks

Two early examples of this evolving threat are HashJack and ShadowLeak, which illustrate prompt injection in practice.

HashJack is a novel prompt injection technique discovered in November 2025 that exploits AI-powered web browsers and agentic AI browser assistants. By hiding malicious instructions within the URL fragment (after the # symbol) of a legitimate, trusted website, attackers can trick AI web assistants into performing malicious actions – potentially inserting phishing links, fake contact details, or misleading guidance directly into what appears to be a trusted AI-generated output.

ShadowLeak is a prompt injection method to exfiltrate PII identified in September 2025. This was a flaw in ChatGPT (now patched by OpenAI) which worked via an agent connected to email. If attackers sent the target an email containing a hidden prompt, the agent was tricked into leaking sensitive information to the attacker with no user action or visible UI.

What’s the risk of email-delivered prompt injection attacks?

Enterprise AI assistants often have complete visibility across emails, documents, and internal platforms. This means an attacker does not need to compromise credentials or move laterally through an environment. If successful, they can influence the AI to retrieve relevant information seamlessly, without the labor of compromise and privilege escalation.

The first risk is data exfiltration. In a prompt injection scenario, malicious instructions may be embedded within an ordinary email. As in the ShadowLeak attack, when AI processes that content as part of a legitimate task, it may interpret the hidden text as an instruction. This could result in the AI disclosing sensitive data, summarizing confidential communications, or exposing internal context that would otherwise require significant effort to obtain.

The second risk is agentic workflow poisoning. As AI systems take on more active roles, prompt injection can influence how they behave over time. An attacker could embed instructions that persist across interactions, such as causing the AI to include malicious links in responses or redirect users to untrusted resources. In this way, the attacker inserts themselves into the workflow, effectively acting as a man-in-the-middle within the AI system.

Why can’t other solutions catch email-delivered prompt injection attacks?

AI prompt injection challenges many of the assumptions that traditional email security is built on. It does not fit the usual patterns of phishing, where the goal is to trick a user into clicking a link or opening an attachment.  

Most security solutions are designed to detect signals associated with user engagement: suspicious links, unusual attachments, or social engineering cues. Prompt injection avoids these indicators entirely, meaning there are fewer obvious red flags.

In this case, the intention is actually the opposite of user solicitation. The objective is simply for the email to be delivered and remain in the inbox, appearing benign and unremarkable. The malicious element is not something the recipient is expected to engage with, or even notice.

Detection is further complicated by the nature of the prompts themselves. Unlike known malware signatures or consistent phishing patterns, injected prompts can vary widely in structure and wording. This makes simple pattern-matching approaches, such as regex, unreliable. A broad rule set risks generating large numbers of false positives, while a narrow one is unlikely to capture the diversity of possible injections.

How does Darktrace catch these types of attacks?

The Darktrace approach to email security more generally is to look beyond individual indicators and assess context, which also applies here.  

For example, our prompt density score identifies clusters of prompt-like language within an email rather than just single occurrences. Instead of treating the presence of a phrase as a blocking signal, the focus is on whether there is an unusual concentration of these patterns in a way that suggests injection. Additional weighting can be applied where there are signs of obfuscation. For example, text that is hidden from the user – such as white font or font size zero – but still readable by AI systems can indicate an attempt to conceal malicious prompts.

This is combined with broader behavioral signals. The same communication context used to detect other threats remains relevant, such as whether the content is unusual for the recipient or deviates from normal patterns.

Ask your email provider about email-delivered AI prompt injection

Prompt injection targets not just employees, but the AI systems they rely on, so security approaches need to account for both.

Though there are clear indications of emerging activity, it remains to be seen how popular prompt injection will be with attackers going forward. Still, considering the potential impact of this attack type, it’s worth checking if this risk has been considered by your email security provider.

Questions to ask your email security provider

  • What safeguards are in place to prevent emails from influencing AI‑driven workflows over time?
  • How do you assess email content that’s benign for a human reader, but may carry hidden instructions intended for AI systems?
  • If an email contains no links, no attachments, and no social engineering cues, what signals would your platform use to identify malicious intent?

Visit the Darktrace / EMAIL product hub to discover how we detect and respond to advanced communication threats.  

Learn more about securing AI in your enterprise.

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About the author
Kiri Addison
Senior Director of Product
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