CVE-2019-25736: LabF nfsAxe 3.7 Buffer Overflow – Local Code Execution

Technical summary

CVE-2019-25736 is a classic stack-based buffer overflow (CWE-120) in LabF nfsAxe 3.7's Ping Client component. The vulnerability stems from insufficient bounds checking on input supplied to the Host IP field. An attacker can construct a specially formatted input file containing shellcode that, when processed, overwrites the return address on the stack. Upon function return, execution jumps to attacker-controlled code, enabling arbitrary code execution. The CVSS 3.1 score of 8.4 (HIGH) reflects local attack surface, no authentication requirement, and complete compromise of confidentiality, integrity, and availability.

Business impact

Organizations using LabF nfsAxe 3.7 for network diagnostics face risk of complete system compromise via local code execution. An adversary with shell access—whether through credential compromise, physical access, or lateral movement—can exploit this flaw to escalate privileges, deploy malware, exfiltrate data, or disrupt operations. The lack of authentication controls means any local user account can trigger the vulnerability. For environments relying on nfsAxe for critical network troubleshooting, exploitation could lead to service interruption or unauthorized system access.

Affected systems

LabF nfsAxe 3.7 Ping Client is the confirmed affected component. Users of LabF nfsAxe version 3.7 should assume their Ping Client deployment is vulnerable. Verify your installed version against LabF's product documentation. Newer versions or vendor patches should be evaluated as part of remediation planning.

Exploitability

Exploitation requires local system access and does not demand elevated privileges or user interaction. An attacker must craft an input file with carefully positioned shellcode and supply it via the Host IP field parameter. While the attack surface is localized to authenticated or compromised user accounts, the straightforward nature of buffer overflows and the well-understood exploitation techniques for stack-based overwrites mean this flaw poses genuine risk in environments with untrusted users or where lateral movement has already occurred.

Remediation

Immediately identify systems running LabF nfsAxe 3.7 and isolate or restrict local access where practical. Contact LabF directly to request a patched version or security advisory. If an update is not available, consider disabling or uninstalling the Ping Client component if operational requirements permit. Enforce principle of least privilege to limit the number of local user accounts capable of invoking the vulnerable application. Monitor file access and process execution related to nfsAxe for anomalous behavior.

Patch guidance

Check LabF's official website or support portal for available patches or version updates addressing CVE-2019-25736. Verify the patch version number and release notes against LabF's advisory to confirm the flaw is resolved. Apply patches through your organization's change management process in a controlled test environment before production deployment. If no patch is forthcoming from the vendor, document your risk acceptance or pursue alternative network diagnostic tools.

Detection guidance

Monitor for suspicious input or file submissions to nfsAxe, particularly unusual payloads in Host IP field entries. Endpoint Detection and Response (EDR) tools should flag unexpected code execution spawned by the nfsAxe process or unusual memory access patterns consistent with buffer overflow exploitation. Stack canary and ASLR defenses on modern operating systems may mitigate some exploitation attempts; verify these protections are enabled. Log file I/O and process execution in directories where nfsAxe stores or processes input files.

Why prioritize this

Although not yet in CISA's Known Exploited Vulnerabilities (KEV) catalog, this HIGH-severity buffer overflow warrants prompt attention because it enables unauthenticated local code execution with no user interaction required. Any successful exploitation grants near-complete system control. Organizations should prioritize patching or containment of LabF nfsAxe 3.7 systems to prevent lateral movement and privilege escalation attacks in environments where multiple user accounts exist on shared systems.

Risk score, explained

The CVSS 3.1 score of 8.4 (HIGH) reflects the combination of: local attack vector (AV:L), low attack complexity (AC:L), no privilege requirement (PR:N), no user interaction (UI:N), and complete impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The score underscores that any local attacker, without needing admin rights or social engineering, can achieve full system compromise. However, organizations should consider their threat model: environments with tightly controlled local access or air-gapped networks face lower practical risk than those with many user accounts or high lateral movement risk.

Frequently asked questions