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September 4, 2024

What you need to know about FAA Security Protection Regulations 2024

This blog gives an overview of the proposed FAA regulations for safeguarding aviation systems and their cyber-physical networks. Read more to discover key points, challenges, and potential solutions for each use case.
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
Daniel Simonds
Director of Operational Technology
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04
Sep 2024

Overview of FAA Rules 2024

Objective

The goal of the Federal Aviation Administration amended rules is to create new design standards that protect airplane systems from intentional unauthorized electronic interactions (IUEI), which can pose safety risks. The timely motivation for this goal is due to the ongoing trend in aircraft design, which features a growing integration of airplane, engine, and propeller systems, along with expanded connectivity to both internal and external data networks and services.

“This proposed rulemaking would impose new design standards to address cybersecurity threats for transport category airplanes, engines, and propellers. The intended effect of this proposed action is to standardize the FAA’s criteria for addressing cybersecurity threats, reducing certification costs and time while maintaining the same level of safety provided by current special conditions.” (1)

Background

Increasing integration of aircraft systems with internal and external networks raises cybersecurity vulnerability concerns.

Key vulnerabilities include:  

  • Field Loadable Software
  • Maintenance laptops
  • Public networks (e.g., Internet)
  • Wireless sensors
  • USB devices
  • Satellite communications
  • Portable devices and flight bags  

Requirements for Applicants

Applicants seeking design approval must:

  • Provide isolation or protection from unauthorized access
  • Prevent inadvertent or malicious changes to aircraft systems
  • Establish procedures to maintain cybersecurity protections

Purpose

“These changes would introduce type certification and continued airworthiness requirements to protect the equipment, systems, and networks of transport category airplanes, engines, and propellers against intentional unauthorized electronic interactions (IUEI)1 that could create safety hazards. Design approval applicants would be required to identify, assess, and mitigate such hazards, and develop Instructions for Continued Airworthiness (ICA) that would ensure such protections continue in service.” (1)

Key points:

  • Introduce new design standards to address cybersecurity threats for transport category airplanes, engines, and propellers.
  • Aim to reduce certification costs and time while maintaining safety levels similar to current special conditions

Applicant Responsibilities for Identifying, Assessing, and Mitigating IUEI Risks

The proposed rule requires applicants to safeguard airplanes, engines, and propellers from intentional unauthorized electronic interactions (IUEI). To do this, they must:

  1. Identify and assess risks: Find and evaluate any potential electronic threats that could harm safety.
  2. Mitigate risks: Take steps to prevent these threats from causing problems, ensuring the aircraft remain safe and functional.

Let’s break down each of the requirements:

Performing risk analysis

“For such identification and assessment of security risk, the applicant would be required to perform a security risk analysis to identify all threat conditions associated with the system, architecture, and external or internal interfaces.”(3)

Challenge

The complexity and variety of OT devices make it difficult and time-consuming to identify and associate CVEs with assets. Security teams face several challenges:

  • Prioritization Issues: Sifting through extensive CVE lists to prioritize efforts is a struggle.
  • Patch Complications: Finding corresponding patches is complicated by manufacturer delays and design flaws.
  • Operational Constraints: Limited maintenance windows and the need for continuous operations make it hard to address vulnerabilities, often leaving them unresolved for years.
  • Inadequate Assessments: Standard CVE assessments may not fully capture the risks associated with increased connectivity, underscoring the need for a contextualized risk assessment approach.

This highlights the need for a more effective and tailored approach to managing vulnerabilities in OT environments.

Assessing severity of risks

“The FAA would expect such risk analysis to assess the severity of the effect of threat conditions on associated assets (system, architecture, etc.), consistent with the means of compliance the applicant has been using to meet the FAA’s special conditions on this topic.” (3)

Challenge

As shown by the MITRE ATT&CK® Techniques for ICS matrices, threat actors can exploit many avenues beyond just CVEs. To effectively defend against these threats, security teams need a broader perspective, considering lateral movement and multi-stage attacks.

Challenges in Vulnerability Management (VM) cycles include:

  • Initiation: VM cycles often start with email updates from the Cybersecurity and Infrastructure Security Agency (CISA), listing new CVEs from the NIST database.
  • Communication: Security practitioners must survey and forward CVE lists to networking teams at facilities that might be running the affected assets. Responses from these teams are inconsistent, leading vulnerability managers to push patches that may not fit within limited maintenance windows.
  • Asset Tracking: At many OT locations, determining if a company is running a specific firmware version can be extremely time-consuming. Teams often rely on spreadsheets and must perform manual checks by physically visiting production floors ("sneaker-netting").
  • Coordination: Plant engineers and centralized security teams must exchange information to validate asset details and manually score vulnerabilities, further complicating and delaying remediation efforts.

Determine likelihood of exploitation

“Such assessment would also need to analyze these vulnerabilities for the likelihood of exploitation.” (3)

Challenge

Even when a vulnerability is identified, its actual impact can vary significantly based on the specific configurations, processes, and technologies in use within the organization. This creates challenges for OT security practitioners:

  • Risk Assessment: Accurately assessing and prioritizing the risk becomes difficult without a clear understanding of how the vulnerability affects their unique systems.
  • Decision-Making: Practitioners may struggle to determine whether immediate action is necessary, balancing the risk of operational downtime against the need for security.
  • Potential Consequences: This uncertainty can lead to either leaving critical systems exposed or causing unnecessary disruptions by applying measures that aren't truly needed.

This complexity underscores the challenge of making informed, timely decisions in OT security environments.

Vulnerability mitigation

“The proposed regulation would then require each applicant to 'mitigate' the vulnerabilities, and the FAA expects such mitigation would occur through the applicant’s installation of single or multilayered protection mechanisms or process controls to ensure functional integrity, i.e., protection.” (3)

Challenge

OT security practitioners face a constant challenge in balancing security needs with the requirement to maintain operational uptime. In many OT environments, especially in critical infrastructure, applying security patches can be risky:

  • Risk of Downtime: Patching can disrupt essential processes, leading to significant financial losses or even safety hazards.
  • Operational Continuity vs. Security: Practitioners often prioritize operational continuity, sometimes delaying timely security updates.
  • Alternative Strategies: To protect systems without direct patching, they must implement compensating controls, further complicating security efforts.

This delicate balance between security and uptime adds complexity to the already challenging task of securing OT environments.

Establishing procedures/playbooks

“Finally, each applicant would be required to include the procedures within their instructions for continued airworthiness necessary to maintain such protections.” (3)

Challenge

SOC teams typically have a lag before their response, leading to a higher dwell time and bigger overall costs. On average, only 15% of the total cost of ransomware is affiliated with the ransom itself (2). The rest is cost from business interruption. This means it's crucial that organizations can respond and recover earlier. 

Darktrace / OT enabling compliance and enhanced cybersecurity

Darktrace's OT solution addresses the complex challenges of cybersecurity compliance in Operational Technology (OT) environments by offering a comprehensive approach to risk management and mitigation.

Key risk management features include:

  • Contextualized Risk Analysis: Darktrace goes beyond traditional vulnerability scoring, integrating IT, OT, and CVE data with MITRE techniques to map critical attack paths. This helps in identifying and prioritizing vulnerabilities based on their exposure, difficulty of exploitation, and network impact.
  • Guidance on Remediation: When patches are unavailable, Darktrace provides alternative strategies to bolster defenses around vulnerable assets, ensuring unpatched systems are not left exposed—a critical need in OT environments where operational continuity is essential.
  • AI-Driven Adaptability: Darktrace's AI continuously adapts to your organization as it grows; refining incident response playbooks bespoke to your environment in real-time. This ensures that security teams have the most up-to-date, tailored strategies, reducing response times and minimizing the impact of security incidents.

Ready to learn more?  

Darktrace / OT doesn’t just offer risk management capabilities. It is the only solution  
that leverages Self-Learning AI to understand your normal business operations, allowing you to detect and stop insider, known, unknown, and zero-day threats at scale.  

Dive deeper into how Darktrace / OT secures critical infrastructure organizations with in-depth insights on its advanced capabilities. Download the Darktrace / OT Solution Brief to explore the technology behind its AI-driven protection and see how it can transform your OT security strategy.

Curious about how Darktrace / OT enhances aviation security? Explore our customer story on Brisbane Airport to see how our solution is transforming security operations in the aviation sector.  

References

  1. https://research-information.bris.ac.uk/ws/portalfiles/portal/313646831/Catch_Me_if_You_Can.pdf
  1. https://www.bleepingcomputer.com/news/security/ransom-payment-is-roughly-15-percent-of-the-total-cost-of-ransomware-attacks/
  1. https://public-inspection.federalregister.gov/2024-17916.pdf?mod=djemCybersecruityPro&tpl=cs
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
Daniel Simonds
Director of Operational Technology

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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

Anomalous Server Activity / New User Agent from Internet Facing System

Anomalous Server Activity / Rare External from Server

Antigena / Network / External Threat / Antigena Suspicious File Block

Antigena / Network / External Threat / Antigena Suspicious File Pattern of Life Block

Device / New User Agent

Device / Internet Facing Device with High Priority Alert

Anomalous File / New User Agent Followed By Numeric File Download

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About the author
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
Your data. Our AI.
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