What kinds of server logs and timestamps indicate viewing or downloading CSAM without a device?
Executive summary
Server-side logs and timestamps that platforms and investigators commonly use to infer viewing or downloading of CSAM include web access logs (client IP, request path, User-Agent, status code, timestamp), CDN/SSL request logs (access time, client IP, SSL protocol/cipher, User-Agent), authentication and VPN/RADIUS logs, and forensic filesystem MACB timestamps and NTFS journals; cloud scanning tools (e.g., Cloudflare’s CSAM Scanning Tool) also preserve blocked-content records and external access logs for forensics [1] [2] [3] [4] [5]. Researchers have traced CSAM consumers without their devices by analyzing malware-stealer logs and server-side logs linking stolen credentials to site accesses [6] [7].
1. Server access logs: the primary trail
Web server access logs record each HTTP(S) request with a timestamp, client IP, requested URL/path, response code and often the User-Agent header. Those entries are the first, most direct indicator that a client requested CSAM-hosting pages or files; platforms that run proactive detection also retain records of which content was flagged or blocked [1] [2]. Cloud providers and CDNs can augment these with cached-content fingerprints and blocked-content dashboards that administrators can query for forensic follow-up [2] [1].
2. SSL/CDN logs that survive TLS termination
When TLS is terminated by a CDN or reverse proxy, SSL request logs can show access time (%t), client IP (%h), SSL protocol and cipher and User-Agent strings — useful when origin servers have only partial logs or when traffic passed through intermediaries [1]. Cloudflare’s CSAM Scanning Tool specifically compares proxied content to known CSAM fingerprints and gives owners a view into blocked content plus guidance to collect external access logs and preserve evidence for legal obligations [2] [5].
3. Authentication, VPN and network-access records
Authentication systems and RADIUS/NPS logs record login attempts, successes and denials tied to usernames, NAS identifiers and source IPs; these are essential for linking an account to an observed access because they show which credential was used and when. Microsoft-focused log analyses emphasize NPS/IAS records with reason codes and NAS IPs as pivotal to reconstructing remote access sessions [3] [8].
4. Malware-stealer and third‑party logs as alternative attribution sources
Investigative research has shown that infostealer malware logs — harvested credentials, cookies, local system metadata and sometimes browsing history — can be aggregated to identify thousands of users who accessed CSAM sites, enabling attribution without seizing the end-user device (Recorded Future / Insikt research summarized in reporting) [6] [7]. Those datasets yield timestamps and site-access indicators that investigators can correlate with server logs to build a timeline.
5. Filesystem timestamps and anti‑forensics
When files are stored on a server or on a device, filesystem timestamps (creation/birth, modified, accessed, metadata-change — MACB) and NTFS journals ($LogFile, $UsnJrnl) are used to place when content arrived, was read, or was altered. Forensic work detects timestamp manipulation and uses contextual correlations to distinguish genuine access from tampering; academic and professional literature warns attackers may alter timestamps and shows methods to detect such manipulation [4] [9] [10].
6. Hash-matching records and classification flags
Platforms that run hash-based detection (PhotoDNA, PDQ, SaferHash) or classifier pipelines log matches to known-CSAM fingerprints and elevate items for review; those match records include timestamps of detection and often the object identifier (file path or URL) and are the legal basis for reporting to authorities [11] [12]. Detection vendors and platform safety teams combine those logs with access logs to confirm who viewed or downloaded content [13] [12].
7. Limits, caveats and competing viewpoints
Server logs show requests, not intent. A logged request can indicate a user clicked a link, an automated bot fetched content, or a proxied cache served a resource; logs alone do not prove a person intentionally viewed CSAM (available sources do not mention explicit legal standards tying particular log entries to criminal culpability). Researchers relying on malware logs raise privacy, legal and reliability concerns because infostealer datasets are incomplete and may misattribute shared or proxied IPs [6]. Platforms’ scanning tools reduce unknown CSAM surface but generate false positives that require human review and external-preservation of logs for lawful process [2] [5].
8. Practical investigative workflow
Best practice from the reporting: preserve raw access and SSL/CDN logs immediately, collect authentication/RADIUS records, export hash-match detection events and blocked-content reports from CSAM scanning tools, and correlate those with filesystem MACB entries and any available infostealer or third‑party telemetry to form a multi-source timeline. Investigators must also be wary of timestamp tampering and use NTFS journals and cross-source correlation to validate sequences [2] [1] [4] [6].
Limitations: available sources do not detail step‑by‑step legal thresholds in every jurisdiction for proving viewing or downloading from logs; practitioners must follow local law and evidentiary standards while preserving audit trails described above [2] [1] [6].