CVE-2025-46419 (High) — DoS via ESP Packet in Westermo WeOS 5 CyberDudeBivash Alert

Executive Summary

Vulnerability: CVE-2025-46419 is a denial-of-service flaw in Westermo WeOS 5 network operating system. A malicious, specially crafted ESP (Encapsulating Security Payload) packet can cause a device reboot — disrupting network availability.
Affected Versions: WeOS versions 5.23.0 and earlier.
Impact: Network devices (routers/switches) can be taken down, affecting availability, operations; possible chained attacks (if reboot loops lead to timing adversary windows).
Status: High severity. Patches released in versions > 5.23.0. Urgent for industrial, SCADA, telecom, field networks using WeOS devices.

Attack vector: Network attacker (or misconfigured peer) sends crafted IPsec ESP packet to WeOS device. Upon processing it, the kernel fails safely, triggering a reboot.
Attack prerequisites: ability to send ESP-encrypted or malformed ESP packet; possibly knowledge of device IP and open IPsec endpoint.
Not remote code execution, but availability loss, possibly repeated.
Adversary lever: ASP-Peer / VPN tunnels or known IPsec endpoints; misconfigured or open endpoints increase risk.

Industrial / field networks using WeOS for routing between field sites (SCADA / telemetry).
Telecom or network backhaul where WeOS routers are used as edge devices.
Organizations using IPsec tunnels to connect remote offices or branches.
DMZ / perimeter routers with ESP endpoints exposed.

ESP packet logs showing malformed or unexpected parameters (length, checksum, replay issues).
Device logs (kernel / OS) showing abrupt reboots, crash events tied to IPsec / ESP processing.
System uptime metrics dropping repeatedly; correlation with traffic spikes on IPsec interfaces.
Packet captures showing ESP packets from external IPs to WeOS device — verify shape/size anomalies.

Upgrade WeOS devices to fixed version (> 5.23.0) (check vendor advisory).
Apply access controls: restrict who can send ESP packets (ACLs on IPsec endpoints); limit exposure to trusted peers only.
Monitoring & Alerting: uptime/reboot detection; IPsec endpoint logs; alert when device restarts unexpectedly.

Deploy packet filters / IPS to drop malformed ESP packets (or restrict ESP to known source IPs / peers).
Enforce rate-limiting / packet inspection at perimeter; consider using firewalls that validate ESP format.
Review and lock down VPN/IPsec configurations; disable any optional or legacy ESP parameter features where vendor allows.

Network redundancy: ensure alternate paths / device failover if critical device rebooted.
Firmware monitoring & patch management for network OS devices in SCADA/OT/telecom environments.
Incident response playbooks for device availability issues.

Likelihood: moderate to high in networked environments with exposed IPsec endpoints and where patches are delayed.
Risk: high for availability, especially mission-critical or field‐deployed devices. Disruption could cascade (if router reboots affect multiple downstream nodes).

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