Blog
/
Network
/
May 23, 2025

Defending the Frontlines: Proactive Cybersecurity in Local Government

To quickly identify and respond to threats before damage occurs, this local government relies on Darktrace to improve network visibility, stop insider threats, protect its email systems, and accelerate incident investigations.
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
The Darktrace Community
Default blog imageDefault blog imageDefault blog imageDefault blog imageDefault blog imageDefault blog image
23
May 2025

Serving a population of over 165,000 citizens, this county government delivers essential services that enhance the quality of life for all of its residents in Florida, United States. From public safety and works to law enforcement, economic development, health, and community services, the county’s cybersecurity strategy plays a foundational role in protecting its citizens.

From flying blind to seeing the bigger picture

Safeguarding data from multiple systems, service providers, and citizens is a key aspect of the County’s Systems Management remit. Protecting sensitive information while enabling smooth engagement with multiple external partners poses a unique challenge; the types of data and potential threats are continuously evolving, but resources – both human and financial – remain consistently tight.

When the Chief Information Officer took on his role in 2024, building out a responsive defense-in-depth strategy was central to achieving these goals. However, with limited resources and complex needs, his small security team was struggling with high alert volumes, inefficient tools, and time-consuming investigations that frequently led nowhere.

Meanwhile, issues like insider threats, Denial of Service (DoS), and phishing attacks were growing; the inefficiencies were creating serious security vulnerabilities. As the CIO put it, he was flying blind. With so much data coming in, security analysts were in danger of missing the bigger picture.

“We would just see a single portion of data that could send us down a rabbit hole, thinking something’s going on – only to find out after spending days, weeks, or even months that it was nothing. If you’re only seeing one piece of the issue, it’s really difficult to identify whether something is a legitimate threat or a false positive.”

Local government’s unique cybersecurity challenges

According to the CIO, even with a bigger team, aligning and comparing all the data into a comprehensive, bigger picture would be a major challenge. “The thing about local government specifically is that it’s a complex security environment. We bring together a lot of different individuals and organizations, from construction workers to people who bring projects into our community to better the County. What we work with varies from day to day.”

The challenge wasn’t just about identifying threats, but also about doing so quickly enough to respond before damage was done. The CIO said this was particularly concerning when dealing with sophisticated threats: “We’re dealing with nation-state attackers nowadays, as opposed to ‘script kiddies.’ There’s no time to lose. We’ve got to have cybersecurity that can respond as quickly as they can attack.”

To achieve this, among the most critical challenges the CIO and his team needed to address were:

  • Contextual awareness and visibility across the network: The County team lacked the granular visibility needed to identify potentially harmful behaviors. The IT team needed a tool that uncovered hidden activities and provided actionable insights, with minimal manual intervention.
  • Augmenting human expertise and improving response times: Hiring additional analysts to monitor the environment is prohibitively expensive for many local governments. The IT team needed a cybersecurity solution that could augment existing skills while automating day-to-day tasks. More effective resource allocation would drive improved response times.
  • Preventing email-based threats: Phishing and malicious email links present a persistent threat. The County team needed a way to flag, identify, and hold suspicious messages automatically and efficiently. Given the team’s public service remit, contextual awareness is crucial to ensuring that no legitimate communications are accidentally blocked. Accuracy is extremely important.
  • Securing access and managing insider threats: Having already managed insider threats posed by former staff members, the IT team wanted to adopt a more proactive, deterrent-based approach towards employee IT resource use, preventing incidents before they could occur.

Proactive cybersecurity

Recognizing these challenges, the CIO and County sought AI-driven solutions capable of acting autonomously to support a lean IT team and give the big picture view needed, without getting lost in false positive alerts.

Ease of deployment was another key requirement: the CIO wanted to quickly establish a security baseline for County that would not require extensive pre-planning or disrupt existing systems. Having worked with Darktrace in previous roles, he knew the solution had the capacity to make the critical connections he was looking for, while delivering fast response times and reducing the burden on security teams.

When every second counts, we want to be as close to the same resources as our attackers are utilizing. We have got to have something that can respond as quickly as they can attack. For the County, that’s Darktrace.” – CIO, County Systems Management Department.

Closing network visibility gaps with Darktrace / NETWORK

The County chose Darktrace / NETWORK for unparalleled visibility into the County’s network. With the solution in place, the CIO and his team were able to identify and address previously hidden activities, uncovering insider threats in unexpected places. For example, one team member had installed an unauthorized anonymizer plug-in on their browser, posing a potentially serious security risk via traffic being sent out to the internet. “Darktrace immediately alerted on it,” said CIO. “We were able to deal with the threat proactively and quickly.”

Darktrace / NETWORK continuously monitored and updated its understanding of the County environment, intelligently establishing the different behaviors and network activity. The end result was a level of context awareness that enabled the team to focus on the alerts that mattered most, saving time and effort.

“Darktrace brings all the data we need together, into one picture. We’re able to see what’s going on at a glance, as opposed to spending time trying to identify real threats from false positives,” said the CIO. The ability to automate actions freed the team up to focus on more complex tasks, with 66% of network response actions being applied autonomously, taking the right action at the right time to stop the earliest signs of threatening activity. This reduced pressure on the County’s team members, while buying valuable containment time to perform deeper investigations.

The agentless deployment advantage

For the CIO, one of the major benefits of Darktrace / NETWORK is that it’s agentless. “Agents alert attackers to the presence of security in your environment, it helps them to understand that there’s something else they need to bring down your defenses,” he said. Using Darktrace to mirror network traffic, the County can maintain full visibility across all network entities without alerting attackers and respond to threatening activity at machine speed. “It allows me to sleep better at night, knowing that this tool can effectively unplug the network cable from that device and bring it offline,” said CIO.

Streamlining investigations with Darktrace Cyber AI Analyst

For lean security teams, contextual awareness is crucial in reducing the burden of alert fatigue. Using Cyber AI Analyst, the County team is able to take the pressure off, automatically investigating every relevant event, and reducing thousands of individual alerts to only a small number of incidents that require manual review.

For the County team, the benefits are clear: 520 investigation hours saved in one month, with an average of just 11 minutes investigation time per incident. For the CIO, Darktrace goes beyond reducing workloads, it actually drives security: “It identifies threats almost instantly, bringing together logs and behaviors into a single, clear view.”

The efficiency gain has been so significant that the CIO believes Darktrace augments capabilities beyond the size of a team of analysts. “You could have three analysts working around the clock, but it’s hard to bring all those logs and behaviors together in one place and communicate everything in a coordinated way. Nothing does that as quickly as Darktrace can.”

Catching the threats from within: Defense in depth with Darktrace / IDENTITY

One of the key benefits of Darktrace for the County was its breadth of capability and responsiveness. “We’re looking at everything from multi-factor authentication, insider threats, distributed denial of service attacks,” said the CIO. “I’ve worked with other products in the past, but I’ve never found a tool as good as Darktrace.”

Further insider threats uncovered by Darktrace / IDENTITY included insecure access practices. Some users had logins and passwords on shared network resources or in plain-text files. Darktrace alerted the security team and the threats were mitigated before serious damage was done.

Darktrace / IDENTITY gives organizations advanced visibility of application user behavior from unusual authentication, password sprays, account takeover, resource theft, and admin abuse. Security teams can take targeted actions including the forced log-off of a user or temporary disabling of an account to give the team time to verify legitimacy.

First line of defense against the number one attack vector: Enhancing email security with Darktrace / EMAIL

Email-based threats, such as phishing, are among the most common attack vectors in modern cybersecurity, and a key vector for ransomware attacks. Post implementation performance was so strong that the organization now plans to retire other tools, cutting costs without compromising on security.

Darktrace / EMAIL was one of the first tools that I implemented when I started here,” said CIO. “I really recognize the value of it in our environment.” In addition to detecting and flagging potentially malicious email, the CIO said an unexpected benefit has been the reinforcement of more security-aware behaviors among end users. “People are checking their junk folders now, alerting us and checking to see if something is legitimate or not.”

The CIO said that, unlike traditional email security tools that basically perform only one function, Darktrace has multiple additional capabilities that deliver extra layers of protection compared to one-dimensional alternatives. For example, AI-employee feedback loops leverage insights gained from individual users to not only improve detection rates, but also provide end users with contextual security awareness training, to enhance greater understanding of the risks.

Straightforward integration, ease of use

The County wanted a powerful, responsive solution – without demanding pre-installation or integration needs, and with maximum ease of use. “The integration is relatively painless,” said the CIO. “That’s another real benefit, you can bring Darktrace into your environment and have it up and running faster than you could ever hire additional analysts to look at the same data.”

The team found that, compared to competing products, where there was extensive setup, overhead, and resources, “Darktrace is almost plug-and-play.” According to the CIO, the solution started ingesting information and providing notifications immediately: “You can turn on defense or response mechanisms at a granular level, for email or network – or both at the same time.”

The County sees Darktrace as an integral part of its cybersecurity strategy into the future. “Having worked with Darktrace in the past, it was an easy decision for me to agree to a multi-year partnership,” said the CIO “As we continue to build out our defense-in-depth strategy, the ability to use Darktrace to manage other data sources and identify new, additional behavior will be crucial to our proactive, risk-based approach.”

Darktrace has the capacity to meet the organization’s need for exceptional responsiveness, without burning out teams. “If you’re not overburdening the teams that you do have with significant workloads, they have a lot more agility to deal with things on the fly,” said the CIO.

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
The Darktrace Community

More in this series

No items found.

Blog

/

Network

/

May 5, 2026

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

Software supply chain attacksDefault blog imageDefault blog image

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

Continue reading
About the author
Nathaniel Jones
VP, Security & AI Strategy, Field CISO

Blog

/

Email

/

May 5, 2026

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

Default blog imageDefault blog image

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.

Continue reading
About the author
Kiri Addison
Senior Director of Product
Your data. Our AI.
Elevate your network security with Darktrace AI