CVE-2025-14972

Executive Summary

CVE-2025-14972 exposes a critical weakness in the DPA (Differential Power Analysis) countermeasures within the SYMCRYPTO engine on SixG301xxx devices. The random number generation used to mask cryptographic operations is insufficiently random and will eventually repeat, allowing an attacker with physical access to recover secret keys (KSU keys) through side-channel analysis. This vulnerability undermines the security guarantees of the hardware cryptographic module, potentially leading to full key compromise and loss of confidentiality for all protected communications and data at rest.

Supply Chain & Package Security

This vulnerability is not related to any open-source package (NPM, PyPI, Go, Ruby). It is a hardware/firmware-level issue in a proprietary SYMCRYPTO engine embedded in SixG301xxx devices. The supply chain risk is limited to the procurement and deployment of these specific hardware units.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Physical (The attacker must have physical access to the device to perform power analysis.)
• Attack Complexity (AC): High (Requires specialized equipment and signal processing expertise.)
• Privileges Required (PR): None (No prior access needed.)
• User Interaction (UI): None (The attack is passive; the device does not need to be interacted with beyond normal operation.)
• Scope (S): Changed (Compromise of the cryptographic module can affect the security of the entire system.)
• Confidentiality (C): High (Complete loss of key secrecy.)
• Integrity (I): High (With keys, an attacker can forge signatures or decrypt/modify data.)
• Availability (A): None (The attack does not affect device availability.)

CVSS Vector String: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N Base Score: 6.8 (Medium)

Threat Level: High due to the potential for complete cryptographic key recovery, despite the high attack complexity.

Deep Dive & Mechanics

The SYMCRYPTO engine implements DPA countermeasures by injecting random noise or using random masks during cryptographic operations. The goal is to decorrelate the power consumption trace from the secret key bits. This vulnerability arises because the random number generator (RNG) used for these countermeasures is flawed.

The Flaw:

1. The RNG has a short period or insufficient entropy, causing the same random values to be reused after a certain number of operations.
2. When the same random mask is used for two different cryptographic operations, the statistical noise cancellation effect of DPA is broken.
3. An attacker can collect multiple power traces. When traces using the same mask are grouped together, the correlation between the power consumption and the key bits becomes detectable.

Impact on KSU Keys: KSU (Key Storage Unit) keys are the master keys used to protect other keys or data. If these keys are derived or used within the SYMCRYPTO engine, they are directly exposed to this attack. Once a KSU key is recovered, the attacker can decrypt all other keys and data protected by it.

Vulnerable vs. Patched Code

No code is available for comparison. The vulnerability is in the hardware/firmware implementation of the RNG within the SYMCRYPTO engine.

• Vulnerable: The RNG in the SYMCRYPTO engine on SixG301xxx devices produces a sequence of random numbers that repeats after a finite (and insufficiently large) number of outputs.
• Patched (Hypothetical): A patched version would use a cryptographically secure random number generator (CSPRNG) with a sufficiently long period, seeded from a true hardware entropy source (e.g., thermal noise, ring oscillator jitter). The countermeasure logic would also ensure that masks are never reused within a cryptographic session.

Exploitation & Lab Setup

Red Team (Offensive)

Objective: Recover a secret key from a SixG301xxx device using DPA.

Lab Setup:

1. Target: SixG301xxx device running vulnerable firmware.
2. Equipment:
   • Digital Oscilloscope (e.g., PicoScope 6404D) with high sampling rate (>1 GS/s).
   • Current probe (e.g., Tektronix TCP0030A) or a shunt resistor on the power supply line.
   • Computer with Python and the chipwhisperer library (or similar DPA tooling).
   • Trigger signal from the device (e.g., a GPIO pin toggled before a crypto operation).
3. Procedure:
   1. Connect the current probe to the device's power supply.
   2. Configure the oscilloscope to capture power traces triggered by the device's cryptographic operation.
   3. Write a Python script using chipwhisperer to:
      • Capture 10,000+ power traces.
      • Perform a DPA attack targeting a specific S-box output in the AES algorithm (assuming AES is used).
      • Use the "Difference of Means" (DoM) test to find the correct key byte.
   4. Due to the RNG flaw, the attacker will observe a higher correlation peak after grouping traces by the repeated random mask. The attack will succeed with fewer traces than a standard DPA attack on a well-protected device.

Example Python Snippet (Conceptual):

import chipwhisperer as cw
scope = cw.scope()
target = cw.target(scope)

# Capture traces
traces = []
for i in range(10000):
    scope.arm()
    target.simpleserial_write('e', plaintext)
    ret = scope.capture()
    trace = scope.get_last_trace()
    traces.append(trace)

# Perform DPA (simplified)
# The key insight is that the RNG repeat will cause a detectable bias
# in the power traces when grouped by the (unknown) mask value.
# Standard DPA algorithms will work, but with higher efficiency.

Blue Team (Defensive)

Objective: Detect and mitigate DPA attacks against SixG301xxx devices.

Detection:

1. Physical Monitoring: Monitor for unusual physical access to devices. DPA requires physical proximity and equipment.
2. Power Analysis Detection: Deploy power anomaly detection systems that can identify the statistical patterns of a DPA attack (e.g., repeated trigger signals, high-frequency power fluctuations).
3. Operational Security: Limit the number of cryptographic operations a device performs before re-keying. This reduces the number of traces an attacker can collect.

Mitigation:

1. Firmware Update: Apply a vendor patch that fixes the RNG (if/when available).
2. Key Rotation: Immediately rotate all KSU keys and any keys derived from them.
3. Physical Security: Place devices in tamper-resistant enclosures with active shielding.
4. Rate Limiting: Implement a rate limiter on cryptographic operations to slow down trace collection.

Indicators of Compromise (IOCs)

• Physical: Unusual equipment (oscilloscope, probes) near the device.
• Behavioral: An unusually high number of cryptographic operations being performed on the device (e.g., repeated encryption of the same plaintext).
• Network: No network-based IOCs, as this is a physical side-channel attack.
• Logs: Device logs may show repeated key usage or failed authentication attempts if the attacker is testing recovered keys.

Detection Engineering

YARA Rule

rule Detect_DPA_Attack_Equipment
{
    meta:
        description = "Detects files or strings related to DPA attack tools"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "chipwhisperer" nocase
        $s2 = "dpa" nocase
        $s3 = "power analysis" nocase
        $s4 = "oscilloscope" nocase
        $s5 = "current probe" nocase
    condition:
        any of ($s1, $s2, $s3, $s4, $s5)
}

Sigma Rule

title: DPA Attack Tool Execution
id: dpa-attack-tool-execution
status: experimental
description: Detects execution of common DPA attack tools
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\python.exe'
            - '\python3.exe'
        CommandLine|contains:
            - 'chipwhisperer'
            - 'dpa'
            - 'power_analysis'
    condition: selection
falsepositives:
    - Legitimate research activities
level: high

Suricata Rule

alert tcp any any -> any any (msg:"Potential DPA Attack - Repeated Crypto Operations"; flow:to_server; content:"|65 6e 63 72 79 70 74|"; threshold: type both, track by_src, count 100, seconds 60; sid:1000001; rev:1;)

Note: This is a generic rule. A real-world rule would need to be tailored to the specific protocol and command structure of the SixG301xxx device.

Remediation & Mitigation

1. Immediate Action:

   • Contact the vendor (Countermeasures) for a firmware patch.
   • Rotate all KSU keys and any keys derived from them.
   • Increase physical security around SixG301xxx devices.

2. Short-Term Mitigation:

   • Implement rate limiting on cryptographic operations.
   • Enable tamper detection and logging on devices.
   • Monitor for physical access attempts.

3. Long-Term Remediation:

   • Apply the vendor's firmware patch once available.
   • Conduct a security audit of all devices using the SYMCRYPTO engine.
   • Consider replacing affected devices with hardware that uses a certified CSPRNG.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Analyst