Critical Threat
IP address 45.135.193.100 is a critical-risk address operated by Pfcloud UG under ASN AS51396 in the Netherlands, assessed at a 10/10 threat level based on 195 total abuse reports sourced from automated honeypot sensors between August and September 2025. The overwhelming majority of recent reports flag the address for web application reconnaissance and probing activity, indicating the host is systematically scanning for vulnerabilities in publicly accessible web services. Despite the high report volume, the activity frequency metric is recorded at zero out of ten, suggesting the hostile behaviour was concentrated in a specific detection window rather than continuously sustained.
The 195 total reports across 20 separate automated honeypot sensors represent a notably concentrated pattern of detection, pointing to deliberate, targeted scanning rather than opportunistic traffic. The network operator, Pfcloud UG, provides services from Netherlands-based infrastructure, a jurisdiction frequently abused for attack infrastructure due to its connectivity and relative anonymity. All 20 of the most recent reports specifically categorise the activity as web application attacks, with supplemental pattern notes describing the behaviour as web app probing. This consistency across independent detection points raises confidence that the activity is intentional and automated rather than misconfigured legitimate traffic.
Web application probing involves systematic probes for known vulnerabilities listed in the OWASP Top 10, including cross-site scripting, path traversal, file inclusion and other input-validation flaws in HTTP-facing services. A host running this activity at volume poses a concrete risk to any publicly accessible web application that has not been protected by a web application firewall, kept current with security patches or audited for insecure configurations. The probing is typically the precursor to exploitation attempts, meaning organisations with unpatched or poorly hardened web services are the most exposed targets.
Site operators should block or rate-limit traffic from this address at the network perimeter firewall and implement a Web Application Firewall rule set covering OWASP Top 10 vectors to neutralise probing patterns. Enforcing strong authentication on all HTTP-exposed administrative interfaces, applying security patches on a routine schedule and conducting periodic penetration testing will reduce the attack surface that this IP and its peers are designed to exploit. Monitoring authentication logs for repeated failed logins and brute-force patterns can provide early warning if the address transitions from reconnaissance to active exploitation. Tools such as fail2ban can be configured to automatically ban addresses exhibiting suspicious request signatures associated with web app probing behaviour.
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