CVE-2025-52457

Executive Summary

CVE-2025-52457 is a medium-severity vulnerability in Gallagher Command Centre Server and HBUS devices, stemming from an Observable Timing Discrepancy (CWE-208). An attacker with physical access to an HBUS device can exploit timing variations in cryptographic operations to extract device-specific keys. This compromises the security of the entire site, as these keys are used for trusted communication within the Gallagher ecosystem. The vulnerability affects multiple versions of Command Centre Server, with patches available for versions 9.10, 9.20, and 9.30. No public exploit code or proof-of-concept is currently available, and the EPSS score is 0.0%, indicating low exploitation activity in the wild.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a proprietary hardware/software ecosystem from Gallagher.

CVSS Breakdown & Threat Level

• CVSS Score: 5.7 (Medium)
• Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector (AV): Physical (AV:P) – Requires physical access to the HBUS device.
• Attack Complexity (AC): Low (AC:L) – The timing attack is straightforward to perform with standard tools.
• Privileges Required (PR): None (PR:N) – No authentication needed.
• User Interaction (UI): None (UI:N) – No user action required.
• Scope (S): Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality (C): High (C:H) – Device-specific keys can be extracted.
• Integrity (I): None (I:N) – No data modification.
• Availability (A): None (A:N) – No denial of service.

Threat Level: Medium. Physical access requirement reduces the attack surface, but successful exploitation can lead to full site compromise.

Deep Dive & Mechanics

The vulnerability lies in the cryptographic key exchange or verification process between HBUS devices and the Command Centre Server. When an HBUS device performs cryptographic operations (e.g., signing, encryption, or authentication), the time taken to complete these operations can vary based on the secret key material. This is a classic timing side-channel attack.

Technical Details:

• CWE-208: Observable Timing Discrepancy – The system does not ensure that operations are performed in constant time, allowing an attacker to measure execution time and infer secret data.
• Attack Vector: Physical access to the HBUS device. The attacker connects a probe or uses a logic analyzer to measure the time of cryptographic operations.
• Impact: Extraction of device-specific keys. These keys are used for mutual authentication and encrypted communication within the Gallagher ecosystem. Once extracted, the attacker can impersonate the device, decrypt traffic, or potentially pivot to other systems.

Affected Components:

• HBUS devices (hardware controllers)
• Command Centre Server versions:
  • 9.30 prior to vCR9.30.251028a (distributed in 9.30.2881 MR3)
  • 9.20 prior to vCR9.20.251028a (distributed in 9.20.3265 MR5)
  • 9.10 prior to vCR9.10.251028a (distributed in 9.10.4135 MR8)
  • All versions of 9.00 and prior

Vulnerable vs. Patched Code

Since this is a hardware/firmware vulnerability, no source code is publicly available. However, the fix involves implementing constant-time cryptographic operations in the HBUS firmware and Command Centre Server software.

Vulnerable Behavior:

• Cryptographic operations (e.g., HMAC, signature verification) are performed using non-constant-time algorithms.
• Example (pseudocode):

  // Vulnerable: timing depends on key byte comparison
  for (i = 0; i < KEY_LEN; i++) {
      if (key[i] != input[i]) {
          return FAIL;
      }
  }
  

Patched Behavior:

• All cryptographic operations are implemented in constant time.
• Example (pseudocode):

  // Patched: constant-time comparison
  int result = 0;
  for (i = 0; i < KEY_LEN; i++) {
      result |= key[i] ^ input[i];
  }
  return (result == 0) ? SUCCESS : FAIL;
  

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• Physical access to an HBUS device (e.g., Gallagher T-series controller).
• Oscilloscope or logic analyzer with high timing resolution (e.g., Saleae Logic Pro).
• Computer with Python and numpy/scipy for statistical analysis.

Lab Setup:

1. Connect the logic analyzer to the HBUS device's communication lines (e.g., RS-485 or Ethernet).
2. Trigger the device to perform a cryptographic operation (e.g., by sending an authentication request).
3. Capture the timing of the operation over multiple trials.

Exploitation Steps:

1. Trigger Collection: Send repeated authentication requests to the HBUS device.
2. Timing Measurement: Use the logic analyzer to measure the time from request to response.
3. Statistical Analysis: Apply timing attack techniques (e.g., statistical analysis of variance) to extract key bits.
4. Key Recovery: Reconstruct the device-specific key from the timing data.

Example Python Script (Conceptual):

import numpy as np
import time

# Simulate timing measurements
def measure_timing(device_ip):
    start = time.time()
    # Send authentication request
    response = send_auth_request(device_ip)
    end = time.time()
    return end - start

# Collect timing samples
timings = []
for _ in range(1000):
    timings.append(measure_timing("192.168.1.100"))

# Analyze timing variations
mean_timing = np.mean(timings)
std_timing = np.std(timings)
print(f"Mean timing: {mean_timing}, Std: {std_timing}")

Blue Team (Defensive)

Detection:

• Monitor for physical access attempts to HBUS devices (e.g., door open sensors, camera feeds).
• Use network monitoring to detect unusual authentication request patterns (e.g., high frequency of requests from a single source).
• Implement anomaly detection on timing of cryptographic operations (if measurable).

Mitigation:

• Apply the patch immediately (upgrade to patched versions).
• Restrict physical access to HBUS devices (e.g., locked enclosures, tamper switches).
• Use additional encryption layers (e.g., TLS) for network communication.

Indicators of Compromise (IOCs)

• Network:
  • Unusual high frequency of authentication requests to HBUS devices.
  • Requests originating from unexpected physical locations (e.g., maintenance ports).
• Physical:
  • Tamper evidence on HBUS device enclosures (e.g., broken seals, scratches).
  • Unauthorized probes or logic analyzers connected to device ports.
• System:
  • Unexpected changes in device configuration or firmware.
  • Logs showing repeated authentication failures followed by success.

Detection Engineering

YARA Rule

rule CVE_2025_52457_Timing_Attack {
    meta:
        description = "Detects potential timing attack indicators on Gallagher HBUS devices"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-52457"
    strings:
        $auth_request = "AUTH_REQ" nocase
        $timing_anomaly = "TIMING_ANOMALY" nocase
    condition:
        $auth_request or $timing_anomaly
}

Sigma Rule

title: Gallagher HBUS Timing Attack Detection
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects potential timing attack on Gallagher HBUS devices
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: gallagher_command_centre
detection:
    selection:
        EventID: 4624
        LogonType: 3
        TargetUserName: 'HBUS*'
    condition: selection
falsepositives:
    - Legitimate high-frequency authentication
level: medium

Suricata Rule

alert tcp any any -> any 443 (msg:"CVE-2025-52457 Gallagher HBUS Timing Attack"; flow:to_server,established; content:"AUTH_REQ"; depth:100; threshold:type both, track by_src, count 100, seconds 60; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade Command Centre Server to the following versions or later:
   • 9.30.2881 (MR3)
   • 9.20.3265 (MR5)
   • 9.10.4135 (MR8)
2. Physical Security: Ensure HBUS devices are in locked, monitored enclosures.
3. Network Segmentation: Isolate HBUS devices on a separate VLAN with strict access controls.

Long-Term Measures:

• Implement constant-time cryptographic libraries in all firmware.
• Conduct regular security audits of physical access controls.
• Monitor for timing anomalies using the provided detection rules.

Workarounds (if patching is not possible):

• Disable unused HBUS ports.
• Use tamper-evident seals on device enclosures.
• Implement additional authentication layers (e.g., client certificates).

Valters IT
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