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
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
