If a file in cloud storage is exposed via a publicly accessible URL, indexed link can the IWF or Project Arachnid or FBI scan it for CSAM through web crawlers?
Executive summary
If a file in cloud storage is exposed via a publicly accessible URL or an indexed link, proactive crawlers run by civil-society bodies such as Project Arachnid and the Internet Watch Foundation (IWF) can and do discover that content by fetching URLs and matching images against known CSAM hashes, then prompting hosting providers for removal; large platform and CDN operators likewise use hash-matching tools and feeds to detect and act on such URLs [1] [2] [3]. Law enforcement involvement (for example, the FBI) is documented as part of reporting and takedown workflows, but sources show NGOs’ crawlers operate autonomously on the open web and send notices to providers rather than relying solely on police-driven crawling [4] [5].
1. How the crawlers work in practice: automated discovery and hash matching
Project Arachnid and the IWF operate web crawlers that visit URLs previously reported to them or discovered by following links, extract media, and compare those files to databases of verified CSAM hashes (PhotoDNA-style hashes and proprietary lists) to make a determination that a URL contains known CSAM; when matches occur the systems generate removal notices for the hosting provider and track responses [1] [2] [5]. These systems are designed to process very large volumes—tens of thousands of images per second in Project Arachnid’s reporting—and are explicitly described as crawling the open internet and indexed links rather than penetrating private or encrypted storage [6] [7].
2. Cloud/CDN interaction and voluntary scanning options
Major infrastructure operators and CDNs have built-in or optional CSAM scanning tools that use hash databases or APIs to scan content they serve; Cloudflare, for example, documents a CSAM Scanning Tool that compares content served through its network and notes engagement with Project Arachnid and similar programs to streamline reporting to upstream providers [3] [8]. Best-practice guidance from Project Arachnid recommends that high-volume services either implement local scanning against known-hash databases or call content-scanning APIs, indicating industry-accepted routes for cloud storage providers to detect exposed CSAM without sharing raw images [9].
3. Limits: what crawlers can’t do or are not described as doing in the reporting
The reporting consistently frames crawlers as operating on publicly accessible URLs, previously reported links, or feeds; they do not claim the ability to access private, authenticated, encrypted, or otherwise non-public cloud storage paths—so a file behind authentication or end‑to‑end encryption would not be discoverable by a web crawler that only follows public links [1] [2]. Sources also stress the systems primarily detect “known” CSAM via hashes, meaning newly created material that hasn’t been hashed into databases or AI‑generated content may evade pure hash-matching unless augmented by classifiers or manual review [2] [10].
4. The role of law enforcement and reporting pathways
While Project Arachnid and IWF send removal notices to hosting providers and track takedowns, they also coordinate with law enforcement and hotlines—NCMEC, national police and international bodies—so discoveries by crawlers can feed criminal investigations when warranted; however, the sources show NGOs proactively crawl and notify providers as their primary operational model rather than acting only through police-led crawling [4] [5] [2]. Specifics about the FBI’s crawling practices are not detailed in these sources, so definitive claims about federal agents running similar public‑web crawlers from the FBI cannot be supported from the provided reporting.
5. Policy tradeoffs, privacy concerns and hidden agendas
The technical ability to crawl public links and hash-match known CSAM brings tradeoffs: NGOs and industry cast proactive crawling as vital victim‑centered work that reduces re‑victimization and drives takedowns [5] [6], while voluntary guidance for infrastructure providers urges use of URL blocklists and scanning of CDN caches—measures that some privacy advocates fear could be repurposed or expand surveillance if not tightly governed [11]. The sources come from organizations invested in takedown effectiveness and platform cooperation (Project Arachnid, IWF, Cloudflare), so their emphasis on scale and automation reflects both the urgent public-interest mission and an implicit agenda to promote their tools and partnerships as the standard response [8] [12].