CVE-2024-41936: Vonets VAR1200-H Path Traversal Flaw

CVE-2024-41936 Overview

CVE-2024-41936 is a directory traversal vulnerability [CWE-22] affecting Vonets industrial WiFi bridge relays and WiFi bridge repeaters running software version 3.3.23.6.9 and prior. An unauthenticated remote attacker can read arbitrary files on the device and bypass authentication by manipulating file path inputs. The flaw is reachable over the network without user interaction or prior credentials. CISA published the issue in ICS Advisory ICSA-24-214-08, signaling its relevance to industrial control environments where these bridges connect operational technology assets to wireless networks.

Critical Impact

Unauthenticated remote attackers can read arbitrary files and bypass authentication on affected Vonets industrial WiFi bridges, exposing credentials and configuration data used to access downstream OT systems.

Affected Products

• Vonets VAR1200-H, VAR1200-L, VAR600-H, VAR11N-300 industrial WiFi bridge relays (firmware 3.3.23.6.9 and prior)
• Vonets VAP11AC, VAP11G, VAP11G-300, VAP11G-500, VAP11G-500S, VAP11N-300, VAP11S, VAP11S-5G WiFi bridge repeaters
• Vonets VBG1200 and VGA-1000 gateway devices

Discovery Timeline

• 2024-08-12 - CVE-2024-41936 published to NVD and disclosed via CISA ICS Advisory ICSA-24-214-08
• 2024-08-20 - Last updated in NVD database

Technical Details for CVE-2024-41936

Vulnerability Analysis

The vulnerability allows an unauthenticated attacker to traverse the device file system using crafted HTTP requests to the management interface. Because the affected firmware does not properly canonicalize or restrict supplied paths, attackers can request files outside the intended web root. Readable targets include configuration files, credential stores, and authentication tokens. Accessing these files enables authentication bypass, because secrets retrieved from the file system can be reused to gain administrative control of the bridge. The impact is amplified in industrial environments, where these bridges often sit between wireless networks and PLCs, HMIs, or other operational technology endpoints.

Root Cause

The root cause is improper limitation of a pathname to a restricted directory [CWE-22] in the device's web management service. User-controlled path components are passed to file-handling routines without normalization checks for sequences such as ../. The service runs without authentication on the endpoints used for file retrieval, removing the only barrier that would otherwise mitigate the traversal.

Attack Vector

Exploitation requires network reachability to the bridge's HTTP management interface. An attacker sends a crafted request whose path or parameter contains traversal sequences targeting sensitive files such as configuration backups or password files. No credentials, user interaction, or local access are required. The vulnerability is therefore exploitable by any network-adjacent attacker, including those who have compromised a Wi-Fi client or pivoted into a flat OT network segment.

No public proof-of-concept exploit code has been released. Technical details and affected device coverage are documented in the CISA ICS Advisory ICSA-24-214-08.

Detection Methods for CVE-2024-41936

Indicators of Compromise

• HTTP requests to Vonets management interfaces containing ../, ..\, or URL-encoded variants such as %2e%2e%2f
• Unauthenticated GET requests successfully retrieving non-web file paths from the bridge
• Access log entries showing retrieval of configuration files, password files, or system files via the web service

Detection Strategies

• Inspect web server access logs on Vonets devices, where available, for path traversal patterns and unusually large numbers of 200 responses to unauthenticated requests
• Deploy IDS/IPS signatures that detect directory traversal sequences in HTTP requests destined to Vonets device IP ranges
• Baseline normal management traffic to the bridges and alert on connections from unexpected source hosts

Monitoring Recommendations

• Forward network flow and HTTP proxy logs from OT/IT boundary devices into a centralized analytics platform for correlation
• Monitor for outbound connections originating from Vonets devices that deviate from baseline, which may indicate post-exploitation activity
• Track configuration changes on downstream OT assets that share credentials with the bridges

How to Mitigate CVE-2024-41936

Immediate Actions Required

• Restrict network access to the Vonets device management interface to a dedicated administrative VLAN or jump host
• Place affected bridges behind a firewall that blocks inbound HTTP from untrusted networks
• Rotate any credentials, pre-shared keys, or certificates stored on affected devices, assuming prior exposure
• Inventory all Vonets bridges and repeaters in production to confirm firmware versions

Patch Information

The CISA advisory states that Vonets had not provided a fix at the time of publication. Refer to the CISA ICS Advisory ICSA-24-214-08 for vendor coordination status and updated remediation guidance. Apply firmware updates released after version 3.3.23.6.9 as soon as the vendor makes them available.

Workarounds

• Disable remote management on the WAN interface and limit administration to a wired, isolated segment
• Enforce network segmentation between the bridges and critical OT assets to limit lateral movement after compromise
• Replace exposed devices with alternative hardware where patch timelines are unacceptable for the environment
• Use a VPN or zero-trust gateway in front of the management interface to require authenticated access