CVE-2025-7432: Silicon Labs Series 2 DPA Vulnerability

CVE-2025-7432 Overview

CVE-2025-7432 is a cryptographic side-channel vulnerability affecting Silicon Labs' Series 2 devices. The Differential Power Analysis (DPA) countermeasures implemented in these devices fail to reseed under certain conditions, potentially allowing an attacker with physical access to extract secret cryptographic keys through sustained DPA attacks.

Critical Impact
Physical attackers may extract secret keys through side-channel analysis due to insufficient entropy reseeding in DPA countermeasures, compromising device security.

Affected Products

Silicon Labs Series 2 Devices
Devices utilizing DPA countermeasure implementations

Discovery Timeline

2026-02-09 - CVE CVE-2025-7432 published to NVD
2026-02-09 - Last updated in NVD database

Technical Details for CVE-2025-7432

Vulnerability Analysis

This vulnerability is classified under CWE-331 (Insufficient Entropy), indicating that the random number generation or reseeding mechanism used by the DPA countermeasures lacks adequate unpredictability. DPA countermeasures are designed to introduce randomness into cryptographic operations to prevent power analysis attacks from correlating power consumption patterns with secret key values.

When these countermeasures are not properly reseeded, the protective randomness becomes predictable over time. An attacker performing continuous power measurements during cryptographic operations can statistically filter out the now-predictable masking patterns, eventually revealing the underlying secret keys. This requires physical access to the device and specialized equipment to capture and analyze power traces.

Root Cause

The root cause is insufficient entropy reseeding in the DPA countermeasure implementation. Under certain operational conditions, the pseudorandom number generator (PRNG) used to mask cryptographic operations does not receive fresh entropy, causing the protective randomness to become stale and potentially predictable. This allows an attacker to perform statistical analysis across multiple power traces to identify correlations that would otherwise be hidden by properly refreshed random masks.

Attack Vector

This vulnerability requires physical access to the target device. An attacker must:

Obtain physical access to a Silicon Labs Series 2 device
Set up power analysis measurement equipment (oscilloscope, current probes)
Trigger repeated cryptographic operations while capturing power traces
Perform statistical DPA analysis to correlate power consumption with key-dependent operations
Exploit the predictable countermeasure patterns to filter noise and extract secret key material

The attack complexity is high, requiring specialized equipment, cryptographic expertise, and extended access time to gather sufficient traces for statistical analysis. For detailed technical information, refer to the Silicon Labs Community Discussion.

Detection Methods for CVE-2025-7432

Indicators of Compromise

Physical tampering evidence on Silicon Labs Series 2 devices
Unusual power measurement probing or modifications to device power supply circuits
Unexpected or unauthorized physical access to deployed IoT or embedded devices
Signs of extended device access beyond normal maintenance windows

Detection Strategies

Implement physical security monitoring and tamper-evident enclosures for deployed devices
Deploy intrusion detection systems for physical access to device deployment areas
Establish baseline power consumption patterns and monitor for anomalous measurement activities
Conduct regular physical security audits of deployed Silicon Labs devices

Monitoring Recommendations

Monitor physical access logs to areas containing vulnerable devices
Implement video surveillance in sensitive device deployment locations
Track firmware versions across device inventory to identify vulnerable units
Establish chain of custody procedures for device handling and maintenance

How to Mitigate CVE-2025-7432

Immediate Actions Required

Conduct an inventory assessment to identify all deployed Silicon Labs Series 2 devices
Evaluate physical security controls protecting vulnerable devices
Review device deployment environments for potential physical access vulnerabilities
Prioritize patching or firmware updates for devices in accessible or high-risk locations

Patch Information

Consult the Silicon Labs Community Discussion for the latest guidance on firmware updates and patches addressing this vulnerability. Contact Silicon Labs support for specific patch availability and deployment instructions for your device configurations.

Workarounds

Enhance physical security measures around deployed devices including locked enclosures and tamper detection
Limit physical access to authorized personnel only with documented access procedures
Consider additional environmental shielding to impede power analysis measurements
Implement device monitoring to detect unauthorized physical interactions
Where possible, rotate or refresh cryptographic keys on a regular schedule to limit the window of exposure