How should companies respond when an answer engine’s crawlers ignore basic site controls and access restricted content tools?
Our blog sets the scene with a clear, calm look at why this matters for the broader security posture of the web. Cloudflare’s report shows declared crawlers making tens of millions of requests daily while stealth crawlers impersonated a standard browser user-agent. They pass the search engine security firewalls by providing the server with flawed information.
Tests on freshly registered domains that used “User-agent: * Disallow: /” and WAF rules still returned results. That gap raises a serious threat to content owners and infrastructure.
We will parse the patterns, compare compliant crawlers with evasive behavior, and explain practical steps companies can take to regain visibility and control. For background, see this detailed report on crawler blocking by Cloudflare and industry responses: Cloudflare crawler findings.
Key Takeaways of Perplexity AI and Cybersecurity
- Declared vs. stealth crawler traffic can mask the actual risk to site performance and increase phishing risks.
- Robots.txt and WAF rules are not always sufficient alone.
- Fingerprinting and heuristic rules help detect obfuscated crawlers.
- Transparency from companies builds trust and supports defense.
- We recommend active monitoring and managed rules to protect content.
Breaking Down the Perplexity AI and Cybersesecurity story: what Cloudflare’s past findings reveal

Cloudflare’s controlled tests exposed a pattern of crawler activity that ignored site-level restrictions.
We unpack the core allegations in plain terms: stealth crawling that evaded robots’ directives, user‑agent spoofing to mimic real browsers, and repeated requests that continued after basic rules were applied.
Customers first raised alarms when a company they had blocked still appeared to access content; consequently, that prompted Cloudflare to conduct tests on newly registered, non-indexed domains configured with “User-agent: * Disallow: ” and protected by WAF rules.
Results showed two distinct crawler classes. Declared bots such as Perplexity-User and PerplexityBot made tens of millions of daily requests. Undeclared crawlers used a Chrome-on-macOS user-agent and generated millions more. Cloudflare then de-listed the verified bot status and deployed heuristics to block stealth activity.
- **Directives** threaten web security and content control.
- Data implications: owners lose governance over how data is discovered and summarized.
- Action: monitor logs, report anomalies, and apply managed rules promptly.
| Aspect | Declared Crawlers | Undeclared Crawlers | Response |
|---|---|---|---|
| Volume | 20–25M requests/day | 3–6M requests/day | Heuristics and de-listing |
| Identification | Perplexity-User, PerplexityBot | Chrome-on-macOS user-agent | Log analysis and fingerprinting |
| Compliance with robots | Claimed | Observed evasion | WAF + managed rules |
| Impact on sites | High crawl volume | Hidden access despite blocks | Restore alignment between directives and access |
For deeper reporting and context on the accusations and tests, see this coverage on a related incident at tech reporting on crawler scraping. We recommend teams treat such reports as triggers to tighten monitoring and update managed rules. This blog aims to support users with new cyber tools.
Inside the crawl: technical behaviors, network signals, and anti-bot countermeasures

Detailed logs reveal how some crawlers mask automated behavior to blend with real users.
Cloudflare logged two distinct classes of traffic. Declared bot headers produced about 20–25 million daily requests. Undeclared clients used a Chrome-on-macOS user-agent string and added roughly 3–6 million more daily requests.
Rotating IPs and multiple ASNs made simple firewall lists ineffective. In fact, that network churn spreads requests across ranges not listed in vendor documentation, which complicates perimeter rules.
Tests on freshly registered, non-indexed domains set to “User-agent: * Disallow:” and protected by WAF still showed retrieval and summarization of files and pages. This study demonstrates that when clients mimic browsers, they can effectively circumvent robots’ directives and basic WAF blocks; consequently, this not only highlights a significant vulnerability but also suggests the need for improved security measures. Furthermore, it is essential to address these weaknesses, as they could lead to potential exploitation in the future. Additionally, understanding this issue is critical for enhancing overall web protection strategies. Moreover, timely interventions can help mitigate these risks, ultimately fostering a safer online environment. Lastly, further research is required to explore these vulnerabilities in depth.
- Fingerprinting: managed rules use TLS, headers, and timing fingerprints to flag stealth activity.
- Scale: millions of daily requests demand bot management and capacity checks.
- Response: crawler de-listing removed trust, prompting heuristic blocks and wider protections.
For detailed reporting and context on the incident and defensive steps, see this coverage on crawler findings: crawler report and response.
Industry standards, comparisons, and business impact for companies and customers
We see a clear split between transparent crawl behavior and covert access. That gap reshapes risk models for the web and company operations.

Comparing compliant practice with alleged stealth tactics
OpenAI is cited as following declared user‑agents, honoring robots directives, stopping when disallowed, and using Web Bot Auth. Cloudflare reports its managed robots.txt and bot block rules protect over 2.5 million websites.
By contrast, reports say some crawlers used browser-like headers to bypass controls. Cloudflare de-listed Perplexity and applied ML fingerprinting across tens of thousands of domains to find that behavior.
Perplexity AI and Cybersecurity: Risks, vulnerabilities, and business impact
- Unexpected load can destabilize a website and strain network systems and their privacy.
- Files intended to remain private could be exposed, thus leading to potential risks to data security and personal reputation.
- Companies face compliance questions, contractual breaches, and regulatory scrutiny.
| Area | Compliant practice | Alleged stealth behavior |
|---|---|---|
| Identification | Declared user‑agents, documented IPs | Browser-like strings, rotating IPs |
| Enforcement | Web Bot Auth, rrobot’s rules | Header-based evasion, heuristic blocks |
| Business impact | Predictable crawl, governed content use | Site outages, content exposure, attacks |
We recommend codifying preferences in directives, tuning managed rules, and using secure firewall layers. For teams planning careers in this field, see our guide for a junior role: junior cybersecurity analyst.
Conclusion
Our analysis reveals that Cloudflare’s data exposes a significant operational flaw: declared Perplexity crawlers made 20–25 million daily requests, while undeclared agents added 3–6 million. This scale of crawling poses a visible threat to data controls and the engine ecosystem, compromising its privacy.
Controlled tests on new, non-indexed domains set to ” ser-agent: * Disallow: /”with WAF rules still returned content. We must treat browser-like behavior by crawlers as a likely stealth risk and track patterns across domains.
We recommend layered defenses: strong, secure firewall policies, adaptive bot rules, rate limits, and ongoing log analysis. Verify robots, enable fingerprinting-based managed rules, and document escalation paths for customers.
Transparent, standards-aligned behavior reduces long-term harm. We will continue our analysis and help stakeholders harden infrastructure against attacks and misuse. For related market context, see this note on valuation and bids: valuation and bids.


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