CVE-2025-20174 in IOS
Summary
by MITRE • 02/05/2025
A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device.
This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMP v2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMP v3, the attacker must have valid SNMP user credentials for the affected system.
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Analysis
by VulDB Data Team • 07/03/2025
The vulnerability identified as CVE-2025-20174 represents a critical weakness within the Simple Network Management Protocol subsystem of Cisco's network operating systems, specifically affecting both IOS and IOS XE software versions. This flaw manifests as inadequate error handling mechanisms during SNMP request processing, creating a pathway for malicious actors to disrupt network operations through deliberate exploitation of the protocol's parsing functions. The vulnerability's impact extends across all major SNMP versions including v1, v2c, and v3, demonstrating the widespread nature of the underlying implementation flaw. Network administrators and security professionals must understand that this weakness exists at the fundamental level of how these devices process management communications, making it particularly dangerous given the critical role SNMP plays in network monitoring and device management.
The technical exploitation of this vulnerability requires an authenticated attacker who can successfully establish a communication channel with the target device using valid SNMP credentials. For SNMP versions 1 and 2c, attackers must possess legitimate read-write or read-only community strings to craft malicious requests that trigger the flawed error handling. In the case of SNMP v3, exploitation requires valid user credentials including appropriate authentication and privacy parameters. The crafted requests leverage the improper error handling mechanism to cause the device to experience an unexpected restart or reload cycle, effectively creating a denial-of-service condition that renders the managed device temporarily inaccessible to legitimate network operations. This type of vulnerability aligns with CWE-248, which describes "Uncaught Exception" conditions where software fails to properly handle exceptional circumstances during processing.
The operational impact of this vulnerability extends beyond simple device unavailability, as network infrastructure devices running affected Cisco software become vulnerable to coordinated attacks that could disrupt critical network services. Organizations relying on SNMP for network monitoring, performance tracking, and device management face significant risks when this vulnerability exists in their network infrastructure. The DoS condition caused by the device reload can result in cascading failures throughout the network, particularly in environments where multiple devices depend on centralized management or where SNMP is used for automated network operations. This vulnerability particularly affects enterprise networks where SNMP is extensively used for monitoring and configuration management, creating potential for widespread service disruption. The attack vector's requirement for authentication makes it less likely to be exploited by casual attackers but still poses a significant threat from insider threats or compromised accounts.
Mitigation strategies for CVE-2025-20174 should prioritize immediate implementation of software updates from Cisco that address the specific error handling flaw in the SNMP subsystem. Network administrators should also implement enhanced access controls and monitoring for SNMP communications, including regular review of SNMP community strings and user credentials to ensure they remain secure. The implementation of network segmentation and access control lists can help limit the potential impact of exploitation by restricting access to SNMP services to only trusted management stations. Organizations should consider implementing additional monitoring for unexpected device reloads or restart patterns that could indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service through protocol manipulation, and defensive measures should incorporate both patch management processes and behavioral monitoring of SNMP traffic for anomalous patterns that could indicate exploitation attempts.