CVE-2023-45858: 
PRTG Network Monitor vulnerability analysis and mitigation

CVE-2023-45858 is a relative path traversal vulnerability in Paessler PRTG Network Monitor that allows unauthenticated remote attackers to read arbitrary local files from the affected server. It affects all PRTG Network Monitor versions prior to 23.4.88.1429. The vulnerability was disclosed and patched in October 2023 with the release of PRTG version 23.4.88.1429. It carries a CVSS v3.1 base score of 8.6 (High) (GitHub Advisory).

The vulnerability is classified as CWE-23 (Relative Path Traversal), arising from improper validation of user-supplied path input within PRTG's web interface. An attacker can craft HTTP requests containing path traversal sequences (e.g., ../) that escape the intended restricted directory, enabling access to arbitrary files on the underlying operating system. No authentication is required, and the attack can be performed remotely over the network with low complexity. No public technical write-ups or proof-of-concept code have been identified at this time (GitHub Advisory, Paessler Helpdesk).

Successful exploitation allows an unauthenticated attacker to read arbitrary local files from the PRTG server, resulting in a high confidentiality impact with a changed scope (affecting resources beyond the vulnerable component itself). Sensitive data at risk includes PRTG configuration files, credentials, API keys, and potentially OS-level files such as password hashes. There is no direct integrity or availability impact, but exposed credentials could facilitate lateral movement or further compromise of monitored network infrastructure (GitHub Advisory).

As of the available intelligence, there is no public proof-of-concept exploit and no evidence of active in-the-wild exploitation. The vulnerability has an EPSS score of 0.0, indicating a very low probability of exploitation in the near term. It has not been added to the CISA Known Exploited Vulnerabilities (KEV) catalog. No threat actor attribution has been reported (GitHub Advisory).

Paessler has released a patch in PRTG Network Monitor version 23.4.88.1429, which resolves this vulnerability. Organizations should upgrade to version 23.4.88.1429 or later as the primary remediation step. As an interim measure until patching is feasible, restrict network access to the PRTG web interface to trusted IP ranges only, and monitor server logs for unusual file access patterns or path traversal sequences in HTTP request logs (Paessler Helpdesk, Paessler Release History).