CVE-2025-46414 Overview
CVE-2025-46414 is a critical authentication flaw affecting EG4 Electronics products. The API governing device registration does not limit the number of PIN entry attempts. An attacker who knows a valid device serial number can brute-force the PIN and gain unauthorized access. The API also returns clear feedback when the correct PIN is supplied, accelerating brute-force attempts. The issue is tracked under [CWE-307: Improper Restriction of Excessive Authentication Attempts]. EG4 patched the flaw in a server-side update deployed on April 6, 2025. CISA published advisory ICSA-25-219-07 describing the vulnerability.
Critical Impact
Unauthenticated attackers can brute-force device PINs over the network and seize control of registered EG4 Electronics devices.
Affected Products
- EG4 Electronics registered devices accessed through the vendor cloud API
- Server-side registration and authentication service operated by EG4 Electronics
- Any deployment relying on the pre-April 6, 2025 PIN validation endpoint
Discovery Timeline
- April 6, 2025 - EG4 Electronics deployed a server-side fix
- August 8, 2025 - CVE-2025-46414 published to NVD
- April 15, 2026 - Last updated in NVD database
Technical Details for CVE-2025-46414
Vulnerability Analysis
The vulnerability stems from missing rate limiting on the PIN validation endpoint used during device registration. The API accepts unlimited authentication attempts for any given device serial number. Attackers can iterate through the PIN keyspace until the server confirms a match. The API compounds the problem by returning unambiguous success and failure responses, which removes any ambiguity for an automated brute-force tool.
This class of weakness is categorized as [CWE-307]. The EPSS score of this CVE remains low because exploitation requires knowledge of a valid device serial number. However, serial numbers are not secret and can often be harvested from packaging, support forums, or predictable enumeration ranges.
Root Cause
The authentication workflow trusts that the PIN alone provides sufficient entropy to deter guessing. No account lockout, exponential back-off, CAPTCHA, or per-IP throttle was enforced on the server side. Combined with verbose response semantics, this design permitted offline-style brute-force speeds against a live network API.
Attack Vector
An attacker with network access to the EG4 cloud API and a valid device serial number issues repeated PIN validation requests. The attacker enumerates the PIN space programmatically and parses the response body or status code for the success indicator. Once the correct PIN is identified, the attacker registers or controls the device under their own account. Because the attack vector is network-based and requires no user interaction, exploitation can be fully automated.
No verified public proof-of-concept code is available. See the CISA ICS Advisory ICSA-25-219-07 for the authoritative technical write-up.
Detection Methods for CVE-2025-46414
Indicators of Compromise
- High volumes of PIN validation requests directed at the EG4 Electronics device registration API from a single source IP or small IP range
- Sequential or dictionary-style PIN values submitted against the same device serial number
- Successful device registration events originating from IP addresses or geolocations that do not match the device owner
- Unexpected account ownership changes or new device pairings on EG4 cloud accounts
Detection Strategies
- Inspect outbound traffic from operational technology networks to EG4 cloud endpoints for abnormal request rates
- Correlate authentication failure telemetry against device serial numbers to identify brute-force patterns
- Alert when a single device serial is associated with more than a small threshold of failed PIN attempts within a short window
Monitoring Recommendations
- Forward EG4 cloud account audit logs to a centralized SIEM for retention and pattern analysis
- Monitor for unexpected device re-registration or ownership transfer notifications
- Track network egress to vendor APIs from inverter and battery management network segments
How to Mitigate CVE-2025-46414
Immediate Actions Required
- Confirm with EG4 Electronics that all cloud-managed devices in your environment are using the post-April 6, 2025 server-side fix
- Audit registered devices in EG4 cloud accounts and remove any unknown registrations
- Rotate PINs on all registered devices and use the maximum supported PIN length and complexity
- Restrict network egress from operational technology segments to only the required EG4 endpoints
Patch Information
EG4 Electronics applied a server-side update on April 6, 2025 that addresses the missing rate limiting on the PIN validation API. No customer-side firmware patch is required because the fix was deployed on the vendor backend. Customers should contact EG4 through the EG4 Electronics Contact Page to verify remediation status for their fleet.
Workarounds
- Place EG4 devices behind a firewall that restricts inbound and outbound traffic to required vendor endpoints only
- Use unique, high-entropy PINs on every registered device to slow any residual brute-force attempts
- Segment inverter and energy storage management networks from general corporate and guest networks
- Subscribe to CISA ICS advisories for ongoing updates on EG4 Electronics products
# Example egress allow-list approach (adapt to your firewall syntax)
# Permit only EG4 cloud endpoints from the OT segment
allow proto tcp from OT_NET to EG4_CLOUD_FQDN port 443
deny proto any from OT_NET to any
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
