The KRVTZ-NET IDS alerts from 2026-01-31 represent a collection of network reconnaissance activities identified through intrusion detection system logs aggregated by the CIRCL OSINT Feed. The alert includes multiple IP addresses linked to suspicious scanning and probing behaviors. One key indicator is the IP 2001:470:2cc:1::27f, which is associated with repeated GET requests to the /remote/logincheck endpoint on Fortigate VPN devices, exploiting CVE-2023-27997. This CVE relates to a vulnerability in Fortigate VPN that allows unauthorized access or denial of service through crafted requests. Other IPs are linked to HTTP User-Agent scanning (e.g., from Censys scanners) and probes targeting hidden environment files or git repositories, which are common reconnaissance techniques used by attackers to gather information about target systems and their configurations. The alert is categorized as low severity and is primarily reconnaissance phase activity within the cyber kill chain, indicating that attackers are gathering intelligence rather than executing active exploitation or payload delivery. There are no patches or direct mitigations linked to this alert, and no known exploits in the wild have been reported for these specific activities. The lack of affected versions and absence of confirmed exploitation suggests this is an observation of ongoing scanning rather than an active breach. The technical details include a unique UUID and timestamp for tracking. The presence of multiple IPs performing diverse reconnaissance techniques suggests a broad scanning campaign, possibly automated and unsupervised, aimed at identifying vulnerable Fortigate VPN endpoints and other web services. This intelligence can be used by defenders to enhance detection and response capabilities.

For European organizations, the primary impact of this threat lies in the reconnaissance activities targeting Fortigate VPN devices and web infrastructure. Successful exploitation of CVE-2023-27997 could lead to unauthorized access, data leakage, or denial of service, potentially disrupting remote access capabilities critical for business continuity. Even though no active exploitation is reported, the scanning activity indicates that threat actors are actively identifying vulnerable targets, increasing the risk of future attacks. Organizations relying on Fortigate VPN for secure remote access, especially those in sectors like finance, government, healthcare, and critical infrastructure, could face elevated risks. Reconnaissance can also lead to targeted phishing or credential stuffing campaigns if attackers gather sufficient information. The low severity rating reflects the current absence of exploitation but does not diminish the importance of proactive defense. The impact on confidentiality, integrity, and availability could escalate if reconnaissance leads to successful exploitation. Additionally, the presence of probes for hidden environment files and git repositories suggests attackers may be seeking sensitive configuration or source code information, which could facilitate further attacks or intellectual property theft.

European organizations should implement targeted mitigation strategies beyond generic advice. First, Fortigate VPN users must ensure their devices are updated with the latest security patches addressing CVE-2023-27997 and related vulnerabilities. If patches are unavailable, apply recommended configuration changes to restrict access to the /remote/logincheck endpoint, such as IP whitelisting, rate limiting, or multi-factor authentication enforcement. Deploy advanced intrusion detection and prevention systems tuned to detect repeated GET requests and anomalous user-agent strings indicative of scanning. Monitor VPN logs for unusual login attempts or repeated failed authentications. Harden web servers by disabling access to hidden environment files and securing git repositories, preferably restricting them to internal networks. Employ network segmentation to isolate VPN infrastructure from critical assets. Conduct regular threat hunting exercises using the provided IP indicators to identify potential compromises early. Finally, raise awareness among security teams about the reconnaissance nature of these alerts to improve incident response readiness and reduce dwell time in case of escalation.