CVE-2025-41654: SNMP Information Disclosure Vulnerability

CVE-2025-41654 Overview

CVE-2025-41654 is a Missing Authentication for Critical Function vulnerability (CWE-306) affecting SNMP protocol implementations. An unauthenticated remote attacker can access information about running processes via the SNMP protocol. The amount of returned data can trigger a reboot by the watchdog, leading to denial of service conditions.

Critical Impact

Unauthenticated attackers can remotely enumerate system processes and potentially cause device reboots through watchdog triggers, combining information disclosure with denial of service capabilities.

Affected Products

• Products utilizing vulnerable SNMP implementations (refer to VDE Security Advisory VDE-2025-011 for specific affected products)

Discovery Timeline

• 2025-05-26 - CVE-2025-41654 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-41654

Vulnerability Analysis

This vulnerability stems from a missing authentication mechanism for critical SNMP functions (CWE-306). The SNMP service exposes process information without requiring proper authentication, allowing any network-accessible attacker to query sensitive system data. The attack is network-based and requires no user interaction or special privileges.

The vulnerability has dual impact: first, it enables information disclosure by allowing attackers to enumerate running processes on the target system. Second, when large volumes of data are requested, the system's watchdog mechanism interprets this as a hung or unresponsive state, triggering an automatic reboot that results in denial of service.

Root Cause

The root cause is the absence of authentication controls on SNMP endpoints that expose process information. The SNMP implementation fails to validate that incoming requests originate from authorized sources before returning sensitive process enumeration data. Additionally, the watchdog implementation lacks proper safeguards to differentiate between legitimate high-volume SNMP responses and actual system hangs.

Attack Vector

The attack is conducted over the network, typically targeting UDP port 161 (default SNMP port). An attacker can send unauthenticated SNMP GET or WALK requests to query process-related OIDs (Object Identifiers). No special privileges or user interaction are required, making this a low-complexity attack with high availability impact.

The attacker sends standard SNMP queries to the vulnerable endpoint, which responds with process information. By issuing requests that trigger large response payloads, the attacker can cause the watchdog timer to expire, forcing a system reboot. This can be repeated to maintain a persistent denial of service condition.

Detection Methods for CVE-2025-41654

Indicators of Compromise

• Unusual volume of SNMP queries from external or unexpected IP addresses targeting process-related OIDs
• Repeated system reboots correlated with SNMP traffic patterns
• SNMP requests originating from unauthorized network segments
• Watchdog-triggered restart events logged in system event logs

Detection Strategies

• Monitor SNMP traffic patterns for anomalous query volumes or unusual source addresses
• Implement network-based intrusion detection rules to flag unauthenticated SNMP requests from untrusted networks
• Configure logging on SNMP services to capture all incoming requests for forensic analysis
• Set up alerts for watchdog-triggered system reboots that coincide with network activity

Monitoring Recommendations

• Deploy network monitoring to track all SNMP traffic at network boundaries
• Implement SIEM correlation rules to identify patterns of SNMP abuse followed by system restarts
• Monitor for reconnaissance activity targeting common SNMP OIDs related to process enumeration
• Review firewall logs for blocked SNMP traffic from unauthorized sources

How to Mitigate CVE-2025-41654

Immediate Actions Required

• Restrict SNMP access to trusted management networks using firewall rules or ACLs
• Disable SNMP services if not required for operational purposes
• Implement SNMPv3 with authentication and encryption where supported
• Review and apply vendor security patches as they become available

Patch Information

Refer to the VDE Security Advisory VDE-2025-011 for specific patch information and vendor guidance. Organizations should monitor this advisory for updates on available fixes and apply patches according to vendor recommendations.

Workarounds

• Configure network segmentation to isolate SNMP-enabled devices from untrusted networks
• Implement strict firewall rules to allow SNMP traffic only from designated management stations
• If SNMPv3 is available, enable authentication and encryption to prevent unauthorized access
• Consider disabling process-related MIB subtrees if they are not required for monitoring
• Adjust watchdog timeout values to accommodate legitimate high-volume SNMP responses where operationally feasible

# Example network-level mitigation using iptables
# Restrict SNMP (UDP 161) to management network only
iptables -A INPUT -p udp --dport 161 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p udp --dport 161 -j DROP

# Log dropped SNMP attempts for monitoring
iptables -A INPUT -p udp --dport 161 -j LOG --log-prefix "SNMP_BLOCKED: "