CVE-2023-6675 is a critical vulnerability classified under CWE-434, which pertains to the unrestricted upload of files with dangerous types. This vulnerability affects the CyberMath product developed by National Keep Cyber Security Services, specifically versions from v1.4 before v1.5. The core issue allows an attacker to upload arbitrary files, including web shells, to the web server hosting CyberMath. This unrestricted file upload flaw means that the application does not properly validate or restrict the types of files users can upload, enabling attackers to place malicious scripts or executables on the server. Once a web shell is uploaded, an attacker can remotely execute arbitrary commands, potentially gaining full control over the affected system. The CVSS 3.1 base score of 9.8 reflects the critical nature of this vulnerability, indicating that it is remotely exploitable without authentication or user interaction, and it impacts confidentiality, integrity, and availability severely. The vulnerability is publicly disclosed as of February 2, 2024, but no known exploits in the wild have been reported yet. However, given the severity and ease of exploitation, it poses a significant risk to organizations using CyberMath v1.4 or earlier. The lack of a patch link suggests that a fix may not yet be publicly available, increasing the urgency for mitigation.

For European organizations using CyberMath v1.4 or earlier, this vulnerability presents a severe risk. Successful exploitation could lead to complete compromise of the affected web servers, resulting in unauthorized access to sensitive data, disruption of services, and potential lateral movement within the network. Confidentiality is at high risk as attackers can access or exfiltrate sensitive information processed or stored by CyberMath. Integrity is compromised because attackers can modify data or system configurations, and availability is threatened through potential denial-of-service conditions caused by malicious payloads or attacker actions. Given CyberMath’s role in cybersecurity services, a compromise could undermine trust and operational security for organizations relying on it. Additionally, the ability to upload web shells without authentication means attackers can automate exploitation at scale, increasing the threat surface. This vulnerability could also be leveraged as a foothold for further attacks, including ransomware deployment or espionage, particularly targeting organizations with critical infrastructure or sensitive data in Europe.

Immediate mitigation steps should include restricting or disabling file upload functionality in CyberMath until a patch is available. Organizations should implement web application firewalls (WAFs) with rules to detect and block web shell signatures and suspicious file uploads. Network segmentation should be enforced to limit the impact of a compromised web server. Monitoring and logging of file upload activities should be enhanced to detect anomalous behavior promptly. If possible, apply strict file type validation and size limits on uploads at the application or proxy level. Organizations should also conduct thorough security audits and penetration testing focused on file upload mechanisms. Until an official patch is released, consider deploying virtual patching techniques via WAFs or reverse proxies. Additionally, ensure that backup and recovery procedures are robust and tested to mitigate potential data loss or ransomware impacts. Finally, maintain heightened alertness for indicators of compromise related to web shells and unauthorized remote command execution.