We are committed to helping anyone on the Internet protect their platform from this kind of misuse. We first launched a CSAM Scanning Tool several years ago to give any website on the Internet the ability to programmatically scan content uploaded to their platform for instances of CSAM in partnership with National Center for Missing and Exploited Children (NCMEC), Interpol, and dozens of other organizations committed to protecting children. That release took technology that was only available to the largest social media platforms and provided it to any website.

However, the tool we offered still required setup work that added friction to its adoption. To help our customers file reports to NCMEC, they needed to create their own credentials. That step of creating credentials and sharing them was too confusing or too much work for small site owners. We did our best helping them with secondary reports, but we needed a method that made this seamless to encourage adoption.

Today’s announcement makes that process significantly easier for site owners, helping them contribute to keeping the Internet safer with even less manual effort. The tool no longer requires website operators to create and provide their own unique NCMEC credentials. The result is that we have seen monthly adoption of the tool increase by 1,600% since the introduction of this change in February.

Services that attempt to flag and stop the spread of CSAM rely on partner organizations, like NCMEC, who maintain lists of hashes of known CSAM. These hashes are numerical representations of images that rely on an algorithm to create a kind of digital fingerprint for a photo. Partners who operate these tools, like Cloudflare, check hashes of content provided against the list maintained by organizations like NCMEC to see if there is a match. You can read about the operation in detail in our previous announcement here.

We rely on fuzzy hashing, a technique that goes beyond simple one-to-one matches. If a photo of CSAM is altered even slightly — by adding a filter, cropping it, or adding some noise — the fingerprint changes completely.

A fuzzy hash, on the other hand, creates a "perceptual fingerprint." Even if an image is modified, its fuzzy hash will remain similar to the original. This allows our tool to identify matches with a high degree of confidence, even if the abuser tries to disguise the content.

The removal of the requirement to share the credential with Cloudflare removes one additional step to deploying and enabling our tool, but site operators are still expected to continue to file their own reports with NCMEC or their regional equivalent.

The process for using the tool is now straightforward and simple:

Enable the Tool: Activate the CSAM Scanning Tool on your Cloudflare zone and verify your notification email address.

Scan and Detect: Our tool scans your cached content for potential CSAM, creating a fuzzy hash of each image. If a match is found with a known bad hash, a detection event is created.

Remediate: Cloudflare blocks the URL to any identified matches and notifies you so that you may take further action.

We believe that the tools for a safer Internet should be available for everyone  — not just a few large companies.

We invite you to enable the CSAM Scanning Tool on your website today. For more technical details on how it works, please visit our developer documentation. We also welcome you to join our community to discuss the technology and help us continue to build a better Internet.

Since Cloudflare’s launch in 2010, we have collaborated with the National Center for Missing and Exploited Children (NCMEC), a US-based clearinghouse for reporting child sexual abuse material (CSAM), and are committed to doing what we can to support identification and removal of CSAM content.

Members of the public, customers, and trusted organizations can submit reports of abuse observed on Cloudflare’s network. A minority of these reports relate to CSAM, which are triaged with the highest priority by Cloudflare’s Trust & Safety team. We will also forward details of the report, along with relevant files (where applicable) and supplemental information to NCMEC.

The process to generate and submit reports to NCMEC involves multiple steps, dependencies, and error handling, which quickly became complex under our original queue-based architecture. In this blog post, we discuss how Cloudflare Workflows helped streamline this process and simplify the code behind it.

When we designed our latest NCMEC reporting system in early 2024, Cloudflare Workflows did not exist yet. We used the Workers platform Queues as a solution for managing asynchronous tasks, and structured our system around them.

Our goal was to ensure reliability, fault tolerance, and automatic retries. However, without an orchestrator, we had to manually handle state, retries, and inter-queue messaging. While Queues worked, we needed something more explicit to help debug and observe the more complex asynchronous workflows we were building on top of the messaging system that Queues gave us.

In our queue-based architecture each report would go through multiple steps:

1. Validate input: Ensure the report has all necessary details.

2. Initiate report: Call the NCMEC API to create a report.

3. Fetch impounded files (if applicable): Retrieve files stored in R2.

4. Upload files: Send files to NCMEC via API.

5. Finalize report: Mark the report as completed.

^{A diagram of our queue-based architecture} 

Each of these steps was handled by a separate queue, and if an error occurred, the system would retry the message several times before marking the report as failed. But errors weren’t always straightforward — for instance, if an external API call consistently failed due to bad input or returned an unexpected response shape, retries wouldn’t help. In those cases, the report could get stuck in an intermediate state, and we’d often have to manually dig through logs across different queues to figure out what went wrong.

Even more frustrating, when handling failed reports, we relied on a "Reaper" — a cron job that ran every hour to resubmit failed reports. Since a report could fail at any step, the Reaper had to deduce which queue failed and send a message to begin reprocessing. This meant:

• Debugging was a nightmare: Tracing the journey of a single report meant jumping between logs for multiple queues.

• Retries were unreliable: Some queues had retry logic, while others relied on the Reaper, leading to inconsistencies.

• State management was painful: We had no clear way to track whether a report was halfway through the pipeline or completely lost, except by looking through the logs.

• Operational overhead was high: Developers frequently had to manually inspect failed reports and resubmit them.

Queues gave us a solid foundation for moving messages around, but it wasn’t meant to handle orchestration. What we’d really done was build a bunch of loosely connected steps on top of a message bus and hoped it would all hold together. It worked, for the most part, but it was clunky, hard to reason about, and easy to break. Just understanding how a single report moved through the system meant tracing messages across multiple queues and digging through logs.

We knew we needed something better: a way to define workflows explicitly, with clear visibility into where things were and what had failed. But back then, we didn’t have a good way to do that without bringing in heavyweight tools or writing a bunch of glue code ourselves. When Cloudflare Workflows came along, it felt like the missing piece, finally giving us a simple, reliable way to orchestrate everything without duct tape.

Once Cloudflare Workflows was announced, we saw an immediate opportunity to replace our queue-based architecture with a more structured, observable, and retryable system. Instead of relying on a web of multiple queues passing messages to each other, we now have a single workflow that orchestrates the entire process from start to finish. Critically, if any step failed, the Workflow could pick back up from where it left off, without having to repeat earlier processing steps, re-parsing files, or duplicating uploads.

With Cloudflare Workflows, each report follows a clear sequence of steps:

1. Creating the report: The system validates the incoming report and initiates it with NCMEC.

2. Checking for impounded files: If there are impounded files associated with the report, the workflow proceeds to file collection.

3. Gathering files: The system retrieves impounded files stored in R2 and prepares them for upload.

4. Uploading files to NCMEC: Each file is uploaded to NCMEC using their API, ensuring all relevant evidence is submitted.

5. Adding file metadata: Metadata about the uploaded files (hashes, timestamps, etc.) is attached to the report.

6. Finalizing the report: Once all files are processed, the report is finalized and marked as complete.

Here’s a simplified version of the orchestrator:

import { WorkflowEntrypoint, WorkflowEvent, WorkflowStep } from 'cloudflare:workers';


export class ReportWorkflow extends WorkflowEntrypoint<Env, ReportType> {
  async run(event: WorkflowEvent<ReportType>, step: WorkflowStep) {
    const reportToCreate: ReportType = event.payload;
    let reportId: number | undefined;


    try {
      await step.do('Create Report', async () => {
        const createdReport = await createReportStep(reportToCreate, this.env);
        reportId = createdReport?.id;
      });


      if (reportToCreate.hasImpoundedFiles) {
        await step.do('Gather Files', async () => {
          if (!reportId) throw new Error('Report ID is undefined.');
          await gatherFilesStep(reportId, this.env);
        });


        await step.do('Upload Files', async () => {
          if (!reportId) throw new Error('Report ID is undefined.');
          await uploadFilesStep(reportId, this.env);
        });


        await step.do('Add File Metadata', async () => {
          if (!reportId) throw new Error('Report ID is undefined.');
          await addFilesInfoStep(reportId, this.env);
        });
      }


      await step.do('Finalize Report', async () => {
        if (!reportId) throw new Error('Report ID is undefined.');
        await finalizeReportStep(reportId, this.env);
      });
    } catch (error) {
      console.error(error);
      throw error;
    }
  }
}

Not only can tasks be broken into discrete steps, but the Workflows dashboard gives us real-time visibility into each report processed and the status of each step in the workflow!

This allows us to easily see active and completed workflows, identify which steps failed and where, and retry failed steps or terminate workflows. These features revolutionize how we troubleshoot issues, providing us with a tool to deep dive into any issues that arise and retry steps with a click of a button.

Below are two dashboard screenshots, one of our running workflows and the second of an inspection of the success and failures of each step in the workflow. Some workflows look slower or “stuck” — that’s because failed steps are retried with exponential backoff. This helps smooth over transient issues like flaky APIs without manual intervention.

^{Cloudflare Workflows Dashboard for our NCMEC Workflow}

^{Cloudflare Workflows Dashboard containing a breakout of the NCMEC Workflow Steps}

Cloudflare Workflows transformed how we handle NCMEC incident reports. What was once a complex, queue-based architecture is now a structured, retryable, and observable process. Debugging is easier, error handling is more robust, and monitoring is seamless. 

If you’re also building larger, multi-step applications, or have an existing Workers application that has started to approach what we ended up with for our incident reporting process, then you can typically wrap that code within a Workflow with minimal changes. Workflows can read from R2, write to KV, query D1 and call other APIs just like any other Worker, but are designed to help orchestrate asynchronous, long-running tasks.

To get started with Workflows, you can head to the Workflows developer documentation and/or pull down the starter project and dive into the code immediately:

$ npm create cloudflare@latest workflows-starter -- 
--template="cloudflare/workflows-starter"

Learn more about Cloudflare Workflows, and about using the Cloudflare CSAM Scanning Tool.

To combat both the increase in phishing attacks and the growing complexity, we have built advanced automation tooling to both detect and take action. 

In the first half of 2024, Cloudflare resolved 37% of phishing reports using automated means, and the median time to take action on hosted phishing reports was 3.4 days. In the second half of 2024, after deployment of our new tooling, we were able to expand our automated systems to resolve 78% of phishing reports with a median time to take action on hosted phishing reports of under an hour.

In this post we dig into some of the details of how we implemented these improvements.

Cloudflare has observed a similar increase in the volume of phishing activity throughout 2023 and 2024. We receive abuse reports from anyone on the Internet that may have seen potentially abusive behaviors from websites using Cloudflare services. Our Trust & Safety investigators and engineers have been tasked with responding to these complaints, and more recently have been using the data from these reports to improve our threat intelligence, brand protection, and email security product offerings.

Cloudflare has always believed in using the vast amounts of traffic that flows through our network to improve threat detection and customer security. This has been at the core of how we protect our customers from DoS attacks and other cybersecurity threats. We've been applying the same concepts our internal teams use to mitigate phishing to improve detection of phishing on our network and our ability to detect and notify our customers about potential risks to their brand.

Prior to last year, phishing abuse reported to Cloudflare relied on manual, human review and intervention to remediate. Trust & Safety (T&S) investigators would have to look at each complaint, the allegations made by the reporter, and the content on the reported websites to make assessments as quickly as possible about whether the website was phishing or malware.

Given the growing scale of our customer base and phishing across the Internet, this became unsustainable. By collecting a group of internal experts on abuse, we were able to tackle this problem by using insights across our network, internal data from our Email Security product, external feeds from trusted sources, and years of abuse report processing data to automatically assess risk of likely phishing and recommend appropriate action.

We built our automated phishing identification on the Cloudflare Developer Platform so that we could meet our scanning demand without concern for how we might scale. This allowed us to focus more on creating a great phishing detection engine and less on the infrastructure required to meet that demand. 

Each URL submitted to our phishing detection Worker begins with an initial scan by the Cloudflare URL Scanner. The scan provides us with the rendered HTML, network requests, and attributes of the site. After scanning, we collect reputational information about the site by submitting the HTML and page resources to our in-house machine learning classifiers; meanwhile, the indicators of compromise (IOCs) are sent to our suite of threat feeds and domain categorization tools to highlight any known malicious sites or site categorizations.

Once we have all of this information collected, we expose it to a set of rules and heuristics that identify the URL as phishing or not based on how T&S investigators have traditionally responded to similar abuse reports and patterns of bad behaviors we’ve observed. Rules will suggest decisions to make against the reports, and remediations to make against harmful content. It is through this process that we were able to convert the manual reviews by T&S investigators into an automated flow of phishing identification. We also recognize that reporters make mistakes or even deliberately try to weaponize abuse processes. Our rules must therefore consider the possibility of false positives, in which reports are created against legitimate websites (intentionally or unintentionally). False positives can erode the trust of our customers and create incidents, so automation must include processes to disregard erroneous reports.

The magic of all of this was the powerful suite of tools on the Cloudflare Developer Platform. Whether it was using KV to store report summaries that could scale indefinitely or Durable Objects to keep running counters of an unlimited number of attributes that could be tracked or leveraged over time, we were able to integrate the solutions quickly allowing us easily add or remove new enrichments with little effort. We also made use of Hyperdrive to access the internal Postgres database that stores our abuse reports, Queues to manage the scanning jobs, Workers AI to run machine learning classifiers, and D1 to store detection logs for efficacy and evaluation review. To tie it all together, the team also deployed a Remix Pages UI to present all the phishing detection engine’s analysis to T&S investigators for follow-on investigations and evaluations of inconclusive results.

^{Architecture of Trust & Safety’s phishing automation detection pipeline}

The same intelligence we’re gathering to expedite and refine abuse report processing isn’t just for abuse response; it’s also used to empower our customers. By analyzing patterns and trends of abusive behaviors — such as identifying common phrases used in phishing attempts, recognizing infrastructure used by malicious actors or spotting coordinated campaigns across multiple domains — we enhance the efficacy of our application security, email security, and threat intelligence products.

For our Brand Protection customers, this translates into a significant advantage: the ability to easily report suspected abuse directly from the Cloudflare dashboard. This feature ensures that potential phishing sites are addressed rapidly, minimizing the risk to your customers and brand reputation. Furthermore, the Trust and Safety team can use this information to take action on similar threats across the Cloudflare network, protecting all customers, even those who aren't Brand Protection users.

Alongside our network-wide efforts, we’ve also been partnering with our customers, as well as experts outside of Cloudflare, to understand trends they are seeing in their own phishing mitigation efforts. By soliciting intelligence regarding the abuse issues that affect the attack’s targets, we can better identify and prevent abuse of Cloudflare products. We’ve been able to use these partnerships and discussions with external organizations to craft highly targeted rules that head off emerging patterns of phishing activity. 

If you believe you’ve identified phishing activity that is passing through Cloudflare’s network, please report it via our abuse reporting form. For technical users who might be interested in a programmatic way to report to us, please review our abuse reporting API documentation.

We invite all of our customers to join us in helping make the Internet safer:

1. Enterprise customers should speak with their Customer Success Manager about enabling Brand Protection, included by default for all enterprise customers. 

2. For existing users of the Brand Protection product, update your brand's assets, so we can better identify the legitimate websites and logos of our customers vs. possible phishing activity.

3. As a Cloudflare customer, make sure your abuse contact is up-to-date in the Cloudflare dashboard.