Perplexity is using stealth, undeclared crawlers to evade website no-crawl directives
We are observing stealth crawling behavior from Perplexity, an AI-powered answer engine. Although Perplexity initially crawls from their declared user agent, when they are presented with a network block, they appear to obscure their crawling identity in an attempt to circumvent the website’s preferences. We see continued evidence that Perplexity is repeatedly modifying their user agent and changing their source ASNs to hide their crawling activity, as well as ignoring — or sometimes failing to even fetch — robots.txt files.
The Internet as we have known it for the past three decades is rapidly changing, but one thing remains constant: it is built on trust. There are clear preferences that crawlers should be transparent, serve a clear purpose, perform a specific activity, and, most importantly, follow website directives and preferences. Based on Perplexity’s observed behavior, which is incompatible with those preferences, we have de-listed them as a verified bot and added heuristics to our managed rules that block this stealth crawling.
We received complaints from customers who had both disallowed Perplexity crawling activity in their robots.txt files and also created WAF rules to specifically block both of Perplexity’s declared crawlers: PerplexityBot and Perplexity-User. Continue reading
Vulnerability disclosure on SSL for SaaS v1 (Managed CNAME)
Earlier this year, a group of external researchers identified and reported a vulnerability in Cloudflare’s SSL for SaaS v1 (Managed CNAME) product offering through Cloudflare’s bug bounty program. We officially deprecated SSL for SaaS v1 in 2021; however, some customers received extensions for extenuating circumstances that prevented them from migrating to SSL for SaaS v2 (Cloudflare for SaaS). We have continually worked with the remaining customers to migrate them onto Cloudflare for SaaS over the past four years and have successfully migrated the vast majority of these customers. For most of our customers, there is no action required; for the very small number of SaaS v1 customers, we will be actively working to help migrate you to SSL for SaaS v2 (Cloudflare for SaaS).
Back in 2017, Cloudflare announced SSL for SaaS, a product that allows SaaS providers to extend the benefits of Cloudflare security and performance to their end customers. Using a “Managed CNAME” configuration, providers could bring their customer’s domain onto Cloudflare. In the first version of SSL for SaaS (v1), the traffic for Custom Hostnames is proxied to the origin based on the IP addresses assigned to the Continue reading
Celebrate Micro-Small, and Medium-sized Enterprises Day with Cloudflare
On June 27, the United Nations celebrates Micro-, Small, and Medium-sized Enterprises Day (MSME) to recognize the critical role these businesses play in the global economy and economic development. According to the World Bank and the UN, small and medium-sized businesses make up about 90 percent of all businesses, between 50-70 percent of global employment, and 50 percent of global GDP. They not only drive local and national economies, but also sustain the livelihoods of women, youth, and other groups in vulnerable situations.
As part of MSME Day, we wanted to highlight some of the amazing startups and small businesses that are using Cloudflare to not only secure and improve their websites, but also build, scale, and deploy new serverless applications (and businesses) directly on Cloudflare's global network.
Cloudflare started as an idea to provide better security and performance tools for everyone. Back in 2010, if you were a large enterprise and wanted better performance and security for your website, you could buy an expensive piece of on-premise hardware or contract with a large, global Content Delivery Network (CDN) provider. Those same types of services were not only unaffordable for most website owners Continue reading
Everything you need to know about NIST’s new guidance in “SP 1800-35: Implementing a Zero Trust Architecture”
For decades, the United States National Institute of Standards and Technology (NIST) has been guiding industry efforts through the many publications in its Computer Security Resource Center. NIST has played an especially important role in the adoption of Zero Trust architecture, through its series of publications that began with NIST SP 800-207: Zero Trust Architecture, released in 2020.
NIST has released another Special Publication in this series, SP 1800-35, titled "Implementing a Zero Trust Architecture (ZTA)" which aims to provide practical steps and best practices for deploying ZTA across various environments. NIST’s publications about ZTA have been extremely influential across the industry, but are often lengthy and highly detailed, so this blog provides a short and easier-to-read summary of NIST’s latest guidance on ZTA.
And so, in this blog post:
We summarize the key items you need to know about this new NIST publication, which presents a reference architecture for Zero Trust Architecture (ZTA) along with a series of “Builds” that demonstrate how different products from various vendors can be combined to construct a ZTA that complies with the reference architecture.
We show how Cloudflare’s Zero Trust product suite can be integrated with offerings from other vendors Continue reading
Cloudflare Log Explorer is now GA, providing native observability and forensics
We are thrilled to announce the General Availability of Cloudflare Log Explorer, a powerful new product designed to bring observability and forensics capabilities directly into your Cloudflare dashboard. Built on the foundation of Cloudflare's vast global network, Log Explorer leverages the unique position of our platform to provide a comprehensive and contextualized view of your environment.
Security teams and developers use Cloudflare to detect and mitigate threats in real-time and to optimize application performance. Over the years, users have asked for additional telemetry with full context to investigate security incidents or troubleshoot application performance issues without having to forward data to third party log analytics and Security Information and Event Management (SIEM) tools. Besides avoidable costs, forwarding data externally comes with other drawbacks such as: complex setups, delayed access to crucial data, and a frustrating lack of context that complicates quick mitigation.
Log Explorer has been previewed by several hundred customers over the last year, and they attest to its benefits:
“Having WAF logs (firewall events) instantly available in Log Explorer with full context — no waiting, no external tools — has completely changed how we manage our firewall rules. I can spot an issue, adjust the Continue reading
Celebrating 11 years of Project Galileo’s global impact
June 2025 marks the 11th anniversary of Project Galileo, Cloudflare’s initiative to provide free cybersecurity protection to vulnerable organizations working in the public interest around the world. From independent media and human rights groups to community activists, Project Galileo supports those often targeted for their essential work in human rights, civil society, and democracy building.
A lot has changed since we marked the 10th anniversary of Project Galileo. Yet, our commitment remains the same: help ensure that organizations doing critical work in human rights have access to the tools they need to stay online. We believe that organizations, no matter where they are in the world, deserve reliable, accessible protection to continue their important work without disruption.
For our 11th anniversary, we're excited to share several updates including:
An interactive Cloudflare Radar report providing insights into the cyber threats faced by at-risk public interest organizations protected under the project.
An expanded commitment to digital rights in the Asia-Pacific region with two new Project Galileo partners.
New stories from organizations protected by Project Galileo working on the frontlines of civil society, human rights, and journalism from around the world.
Tracking and reporting on cyberattacks with the Project Galileo Continue reading
Resolving a request smuggling vulnerability in Pingora
On April 11, 2025 09:20 UTC, Cloudflare was notified via its Bug Bounty Program of a request smuggling vulnerability in the Pingora OSS framework discovered by a security researcher experimenting to find exploits using Cloudflare’s Content Delivery Network (CDN) free tier which serves some cached assets via Pingora.
Customers using the free tier of Cloudflare’s CDN or users of the caching functionality provided in the open source pingora-proxy and pingora-cache crates could have been exposed. Cloudflare’s investigation revealed no evidence that the vulnerability was being exploited, and was able to mitigate the vulnerability by April 12, 2025 06:44 UTC within 22 hours after being notified.
The bug bounty report detailed that an attacker could potentially exploit an HTTP/1.1 request smuggling vulnerability on Cloudflare’s CDN service. The reporter noted that via this exploit, they were able to cause visitors to Cloudflare sites to make subsequent requests to their own server and observe which URLs the visitor was originally attempting to access.
We treat any potential request smuggling or caching issue with extreme urgency. After our security team escalated the vulnerability, we began investigating immediately, took steps to disable traffic to vulnerable components, and deployed Continue reading
Vulnerability transparency: strengthening security through responsible disclosure
In an era where digital threats evolve faster than ever, cybersecurity isn't just a back-office concern — it's a critical business priority. At Cloudflare, we understand the responsibility that comes with operating in a connected world. As part of our ongoing commitment to security and transparency, Cloudflare is proud to have joined the United States Cybersecurity and Infrastructure Security Agency’s (CISA) “Secure by Design” pledge in May 2024.
By signing this pledge, Cloudflare joins a growing coalition of companies committed to strengthening the resilience of the digital ecosystem. This isn’t just symbolic — it's a concrete step in aligning with cybersecurity best practices and our commitment to protect our customers, partners, and data.
A central goal in CISA’s Secure by Design pledge is promoting transparency in vulnerability reporting. This initiative underscores the importance of proactive security practices and emphasizes transparency in vulnerability management — values that are deeply embedded in Cloudflare’s Product Security program. We believe that openness around vulnerabilities is foundational to earning and maintaining the trust of our customers, partners, and the broader security community.
Transparency in vulnerability reporting is essential for building trust between companies and customers. In 2008, Continue reading
How we simplified NCMEC reporting with Cloudflare Workflows
Cloudflare plays a significant role in supporting the Internet’s infrastructure. As a reverse proxy by approximately 20% of all websites, we sit directly in the request path between users and the origin, helping to improve performance, security, and reliability at scale. Beyond that, our global network powers services like delivery, Workers, and R2 — making Cloudflare not just a passive intermediary, but an active platform for delivering and hosting content across the 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 Continue reading
Cloudflare’s commitment to CISA Secure-By-Design pledge: delivering new kernels, faster
As cyber threats continue to exploit systemic vulnerabilities in widely used technologies, the United States Cybersecurity and Infrastructure Agency (CISA) produced best practices for the technology industry with their Secure-by-Design pledge. Cloudflare proudly signed this pledge on May 8, 2024, reinforcing our commitment to creating resilient systems where security is not just a feature, but a foundational principle.
We’re excited to share and provide transparency into how our security patching process meets one of CISA’s goals in the pledge: Demonstrating actions taken to increase installation of security patches for our customers.
Managing and deploying Linux kernel updates is one of Cloudflare’s most challenging security processes. In 2024, over 1000 CVEs were logged against the Linux kernel and patched. To keep our systems secure, it is vital to perform critical patch deployment across systems while maintaining the user experience.
A common technical support phrase is “Have you tried turning it off and then on again?”. One may be surprised how often this tactic is used — it is also an essential part of how Cloudflare operates at scale when it comes to applying our most critical patches. Frequently restarting systems exercises the Continue reading
Worth Reading: Why Quantum Crypto is Bollocks
Today is a perfect day to point out the fantastic Why Quantum Cryptanalysis is Bollocks presentation (HT: A blog post by George Michaelson)
It’s a must-read, even if you’re absolutely uninterested in the topic. Just replace “Quantum mumbo-jumbo” with AI or SDN ;) Have fun!
Cloudflare for AI: supporting AI adoption at scale with a security-first approach
AI is transforming businesses — from automated agents performing background workflows, to improved search, to easier access and summarization of knowledge.
While we are still early in what is likely going to be a substantial shift in how the world operates, two things are clear: the Internet, and how we interact with it, will change, and the boundaries of security and data privacy have never been more difficult to trace, making security an important topic in this shift.
At Cloudflare, we have a mission to help build a better Internet. And while we can only speculate on what AI will bring in the future, its success will rely on it being reliable and safe to use.
Today, we are introducing Cloudflare for AI: a suite of tools aimed at helping businesses, developers, and content creators adopt, deploy, and secure AI technologies at scale safely.
Cloudflare for AI is not just a grouping of tools and features, some of which are new, but also a commitment to focus our future development work with AI in mind.
Let’s jump in to see what Cloudflare for AI can deliver for developers, security teams, and content creators…
If you Continue reading
Take control of public AI application security with Cloudflare’s Firewall for AI
Imagine building an LLM-powered assistant trained on your developer documentation and some internal guides to quickly help customers, reduce support workload, and improve user experience. Sounds great, right? But what if sensitive data, such as employee details or internal discussions, is included in the data used to train the LLM? Attackers could manipulate the assistant into exposing sensitive data or exploit it for social engineering attacks, where they deceive individuals or systems into revealing confidential details, or use it for targeted phishing attacks. Suddenly, your helpful AI tool turns into a serious security liability.
Today, as part of Security Week 2025, we’re announcing the open beta of Firewall for AI, first introduced during Security Week 2024. After talking with customers interested in protecting their LLM apps, this first beta release is focused on discovery and PII detection, and more features will follow in the future.
If you are already using Cloudflare application security, your LLM-powered applications are automatically discovered and protected, with no complex setup, no maintenance, and no extra integration needed.
Firewall for AI is an inline security solution that protects user-facing LLM-powered applications from Continue reading
Improved Bot Management flexibility and visibility with new high-precision heuristics
Within the Cloudflare Application Security team, every machine learning model we use is underpinned by a rich set of static rules that serve as a ground truth and a baseline comparison for how our models are performing. These are called heuristics. Our Bot Management heuristics engine has served as an important part of eight global machine learning (ML) models, but we needed a more expressive engine to increase our accuracy. In this post, we’ll review how we solved this by moving our heuristics to the Cloudflare Ruleset Engine. Not only did this provide the platform we needed to write more nuanced rules, it made our platform simpler and safer, and provided Bot Management customers more flexibility and visibility into their bot traffic.
In Cloudflare’s bot detection, we build heuristics from attributes like software library fingerprints, HTTP request characteristics, and internal threat intelligence. Heuristics serve three separate purposes for bot detection:
Bot identification: If traffic matches a heuristic, we can identify the traffic as definitely automated traffic (with a bot score of 1) without the need of a machine learning model.
Train ML models: When traffic matches our heuristics, we create labelled datasets Continue reading
Unleashing improved context for threat actor activity with our Cloudforce One threat events platform
Today, one of the greatest challenges that cyber defenders face is analyzing detection hits from indicator feeds, which provide metadata about specific indicators of compromise (IOCs), like IP addresses, ASNs, domains, URLs, and hashes. While indicator feeds have proliferated across the threat intelligence industry, most feeds contain no contextual information about why an indicator was placed on the feed. Another limitation of most feeds today is that they focus solely on blockable indicators and cannot easily accommodate more complex cases, such as a threat actor exploiting a CVE or an insider threat. Instead, this sort of complex threat intelligence is left for long form reporting. However, long-form reporting comes with its own challenges, such as the time required for writing and editing, which can lead to significant delays in releasing timely threat intelligence.
To help address these challenges, we are excited to launch our threat events platform for Cloudforce One customers. Every day, Cloudflare blocks billions of cyber threats. This new platform contains contextual data about the threats we monitor and mitigate on the Cloudflare network and is designed to empower security practitioners and decision makers with actionable insights from a global perspective.
On average, we process 71 Continue reading
One platform to manage your company’s predictive security posture with Cloudflare
In today’s fast-paced digital landscape, companies are managing an increasingly complex mix of environments — from SaaS applications and public cloud platforms to on-prem data centers and hybrid setups. This diverse infrastructure offers flexibility and scalability, but also opens up new attack surfaces.
To support both business continuity and security needs, “security must evolve from being reactive to predictive”. Maintaining a healthy security posture entails monitoring and strengthening your security defenses to identify risks, ensure compliance, and protect against evolving threats. With our newest capabilities, you can now use Cloudflare to achieve a healthy posture across your SaaS and web applications. This addresses any security team’s ultimate (daily) question: How well are our assets and documents protected?
A predictive security posture relies on the following key components:
Real-time discovery and inventory of all your assets and documents
Continuous asset-aware threat detection and risk assessment
Prioritised remediation suggestions to increase your protection
Today, we are sharing how we have built these key components across SaaS and web applications, and how you can use them to manage your business’s security posture.
Regardless of the applications you have connected to Cloudflare’s global network, Cloudflare actively scans Continue reading
Cloudflare enables native monitoring and forensics with Log Explorer and custom dashboards
In 2024, we announced Log Explorer, giving customers the ability to store and query their HTTP and security event logs natively within the Cloudflare network. Today, we are excited to announce that Log Explorer now supports logs from our Zero Trust product suite. In addition, customers can create custom dashboards to monitor suspicious or unusual activity.
Every day, Cloudflare detects and protects customers against billions of threats, including DDoS attacks, bots, web application exploits, and more. SOC analysts, who are charged with keeping their companies safe from the growing spectre of Internet threats, may want to investigate these threats to gain additional insights on attacker behavior and protect against future attacks. Log Explorer, by collecting logs from various Cloudflare products, provides a single starting point for investigations. As a result, analysts can avoid forwarding logs to other tools, maximizing productivity and minimizing costs. Further, analysts can monitor signals specific to their organizations using custom dashboards.
Log Explorer stores your Cloudflare logs for a 30-day retention period so that you can analyze them natively and in a single interface, within the Cloudflare Dashboard. Cloudflare log data is diverse, reflecting the breadth of capabilities Continue reading
Extending Cloudflare Radar’s security insights with new DDoS, leaked credentials, and bots datasets
Security and attacks continues to be a very active environment, and the visibility that Cloudflare Radar provides on this dynamic landscape has evolved and expanded over time. To that end, during 2023’s Security Week, we launched our URL Scanner, which enables users to safely scan any URL to determine if it is safe to view or interact with. During 2024’s Security Week, we launched an Email Security page, which provides a unique perspective on the threats posed by malicious emails, spam volume, the adoption of email authentication methods like SPF, DMARC, and DKIM, and the use of IPv4/IPv6 and TLS by email servers. For Security Week 2025, we are adding several new DDoS-focused graphs, new insights into leaked credential trends, and a new Bots page to Cloudflare Radar. We are also taking this opportunity to refactor Radar’s Security & Attacks page, breaking it out into Application Layer and Network Layer sections.
Below, we review all of these changes and additions to Radar.
Since Cloudflare Radar launched in 2020, it has included both network layer (Layers 3 & 4) and application layer (Layer 7) attack traffic insights on a single Security & Attacks page. Over Continue reading