CVE-2025-55067: TLS4B ATG System DoS Vulnerability

CVE-2025-55067 Overview

CVE-2025-55067 affects the Veeder-Root TLS4B Automatic Tank Gauge (ATG) system. The vulnerability stems from improper handling of Unix time values that exceed the Year 2038 epoch rollover [CWE-190]. When the system clock reaches January 19, 2038, the time counter resets to December 13, 1901. This rollover disrupts authentication, history visibility, and leak detection termination logic.

An authenticated attacker can manipulate the system time to trigger denial of service conditions. The resulting failures include administrative lockout, operational timer corruption, and invalid log entries. CISA published the vulnerability under ICS Advisory ICSA-25-296-03.

Critical Impact
Time manipulation against TLS4B ATG systems forces an integer overflow that locks out administrators, disables leak detection timers, and corrupts audit logs on industrial fuel tank monitoring infrastructure.

Affected Products

Veeder-Root TLS4B Automatic Tank Gauge (ATG) System
TLS4B firmware versions handling 32-bit signed Unix timestamps
Industrial Control System deployments using TLS4B for fuel tank monitoring

Discovery Timeline

2025-10-23 - CVE-2025-55067 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-55067

Vulnerability Analysis

The TLS4B ATG system stores time as a 32-bit signed integer representing seconds since the Unix epoch (January 1, 1970). The maximum value this representation can hold is 2,147,483,647, which corresponds to 03:14:07 UTC on January 19, 2038. Incrementing the counter past this value rolls it into the negative integer range. The system interprets the resulting negative value as December 13, 1901.

Core system functions rely on monotonically increasing time values. Authentication tokens, session timers, history queries, and leak detection routines all read this clock. When time appears to move backward by 137 years, session validation logic, certificate checks, and scheduled tasks fail. An attacker with low-privilege network access can accelerate this condition by directly setting the system clock near the rollover boundary.

Root Cause

The root cause is the use of a 32-bit signed time_t data structure without overflow protection. The CWE-190 classification identifies this as an integer overflow or wraparound defect. The firmware does not validate that time inputs stay within a safe operational range, and downstream consumers of the time value do not detect the negative result.

Attack Vector

The attack requires network access and low-level authenticated privileges on the TLS4B device. An attacker submits a time configuration change pushing the clock past the 2038 boundary. The device then enters a degraded state where administrators cannot log in, leak detection cycles fail to terminate, and historical records become unreadable. No user interaction is required to trigger the cascading failures after the time is set.

The vulnerability is described in prose only as no verified proof-of-concept code has been published. See the CISA ICS Advisory ICSA-25-296-03 for vendor-specific technical detail.

Detection Methods for CVE-2025-55067

Indicators of Compromise

TLS4B system logs reporting timestamps near or after 2038-01-19 03:14:07 UTC or dated 1901-12-13
Unexpected administrative login failures coinciding with recent time configuration changes
Leak detection cycles that fail to terminate or report negative elapsed-time values
Gaps or non-monotonic entries in ATG history logs and audit trails

Detection Strategies

Monitor configuration change events on TLS4B devices for time or NTP server modifications by low-privilege accounts
Alert on authentication failure spikes following any system clock adjustment
Compare device-reported time against an external trusted NTP source and flag deviations greater than one hour
Parse syslog forwarded from ATG units for date strings outside the expected operational window

Monitoring Recommendations

Forward TLS4B audit logs to a centralized log management or SIEM platform for retention and correlation
Establish baselines for normal leak detection cycle duration and alert on anomalies
Track all network connections to TLS4B management interfaces and restrict source addresses

How to Mitigate CVE-2025-55067

Immediate Actions Required

Apply the firmware update from Veeder-Root as referenced in CISA ICS Advisory ICSA-25-296-03
Remove TLS4B management interfaces from direct internet exposure and place them behind a firewall
Restrict time configuration privileges to a minimal set of authenticated administrators
Validate current system time on all TLS4B units and correct any drift before the 2038 boundary

Patch Information

Veeder-Root provides remediation guidance through the Veeder Network Security Reminder and the CISA ICS Advisory. The associated GitHub CSAF file provides machine-readable product and remediation data. Operators should contact Veeder-Root support to obtain the firmware version that corrects the 32-bit time handling.

Workarounds

Isolate TLS4B devices on a dedicated OT network segment with no inbound internet routing
Enforce strong authentication on all administrative accounts and rotate default credentials
Disable remote time configuration where the device supports local-only clock management
Use a trusted internal NTP source to prevent attacker-controlled time updates from being accepted

bash

# Example firewall rule restricting TLS4B management access to a jump host
iptables -A INPUT -p tcp --dport 443 -s 10.10.20.5 -d <tls4b_ip> -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -d <tls4b_ip> -j DROP