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The MacGregor VDR G4e web interface exposes a sensitive file‑editing function that allows any authenticated administrator to directly modify authentication‑related files. Normally, operations such as changing a user’s password are mediated by back‑end logic that validates the request and ensures that only the intended user context is affected. However, the affected endpoint lacks adequate access controls; it receives a file path and new content, then writes the provided data to the specified location without verifying whether the target file is a legitimate configuration file or a critical system file like `/etc/shadow` or /etc/passwd.
An attacker with administrative credentials can abuse this functionality to overwrite the root password entry. Because the web server runs with elevated privileges (often as the `root` user on embedded VDR devices), the file‑write operation succeeds, effectively changing the root password to a value chosen by the attacker. This undermines the integrity of the entire system and grants the attacker full control over the VDR, including the ability to disable logging, alter recorded voyage data, or use the device as a foothold into the ship’s network.
The vulnerability is exacerbated by the fact that the administrative web interface is often exposed to the vessel’s IT network and, in many configurations, reachable from the internet via remote‑access services. Once the root password is changed, the legitimate administrator loses access, and the attacker can lock out the original operator while maintaining persistent, hidden access. The issue is classified as an improper access control weakness (CWE‑284) and carries a CVSS v3.1 base score of 5.7 (Medium). The vector is AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N, indicating a low‑complexity attack that requires high‑level privileges but can be executed remotely. The exploit does not require any user interaction beyond the initial authentication.
DailyCVE Form:
Platform: ……. Danelec MacGregor VDR G4e
Version: …….. V5.250 and prior
Vulnerability :… Improper access control (CWE‑284)
Severity: ……. Medium (CVSS 5.7)
date: ………. 2026‑05‑30
Prediction: ….. Patch expected 2026‑06‑15
What Undercode Say:
Check if the VDR web interface is reachable nmap -p 80,443,8080 <vdr-ip> Authenticate to the web portal (example using curl) curl -X POST http://<vdr-ip>/login.cgi -d "user=admin&pass=default" -c cookies.txt Read the current root password hash (if the file is readable) curl -X GET http://<vdr-ip>/admin/file?path=/etc/shadow -b cookies.txt Overwrite the root password with a chosen hash (e.g., "$6$somesalt$...") curl -X POST http://<vdr-ip>/admin/savefile \ -b cookies.txt \ -d "file=/etc/shadow&content=$6$abcdefg$newhashvalue" Verify that the root password has been changed ssh root@<vdr-ip> Use the new password
Exploit:
An attacker with valid administrator credentials (often default credentials like `admin:admin` because the device does not enforce password change) can craft a POST request to the file‑editing endpoint. The request contains the absolute path of a sensitive file and the new content to be written. The endpoint does not sanitise the path, allowing the attacker to point to /etc/shadow. By replacing the root entry with a hash generated from a known password, the attacker gains immediate root access via SSH or the console. The attack is silent, does not trigger any file‑integrity alarms because the file is overwritten legitimately, and leaves no trace in the web logs beyond the initial administrative login.
Protection:
- Upgrade the VDR firmware to version V5.250 or later, which removes the direct file‑editing functionality from the web interface.
- Restrict access to the administrative web interface to trusted IP addresses only (e.g., via a network firewall or ACL).
- Enforce strong, unique administrator passwords and change them regularly.
- Disable the web interface entirely if remote administration is not required, and rely on local console access for configuration.
- Implement file‑integrity monitoring (e.g., `AIDE` or
Tripwire) on/etc/passwd,/etc/shadow, and other critical system files.
Impact:
Successful exploitation gives an attacker full root privileges on the Voyage Data Recorder. This allows them to:
– Modify or delete voyage data, compromising forensic investigations.
– Disable alarms and safety‑critical notifications.
– Use the VDR as a pivot point to attack other onboard systems (navigation, radar, engine control).
– Install persistent backdoors or malware.
– Lock out legitimate operators, causing operational disruption or denial of service.
Because the VDR is a mandatory safety device aboard commercial vessels, any compromise can lead to regulatory non‑compliance, financial penalties, and increased risk of marine accidents.
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Sources:
Reported By: nvd.nist.gov
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