Cisco SNMP Vulnerability: High-Severity Flaw in IOS and IOS XE Software
A significant security vulnerability has been identified in Cisco's IOS Software and IOS XE Software, which could allow remote attackers to execute arbitrary code or cause a denial-of-service (DoS) condition. This flaw, tracked as CVE-2025-20352 with a CVSS score of 7.7, has been actively exploited in the wild. The vulnerability is rooted in the Simple Network Management Protocol (SNMP) subsystem and arises from a stack overflow condition. It affects all versions of SNMP, including Meraki MS390 and Cisco Catalyst 9300 Series Switches running Meraki CS 17 and earlier.
The vulnerability can be exploited by an authenticated remote attacker who sends a crafted SNMP packet to an affected device over IPv4 or IPv6 networks. Depending on the attacker's privileges, this could result in a DoS condition or arbitrary code execution as root, allowing full control over the system. Cisco has released a fix in IOS XE Software Release 17.15.4a, but no workarounds are available for CVE-2025-20352. The company suggests limiting SNMP access to trusted users and monitoring systems using specific commands.
This development highlights the ongoing risks associated with network management protocols and the importance of maintaining up-to-date software versions. Organizations using affected Cisco devices should prioritize applying the available patches and reviewing their SNMP configurations to mitigate potential exploitation.
Threats and Vulnerabilities
The primary threat posed by CVE-2025-20352 is the potential for remote code execution or DoS attacks on vulnerable Cisco devices. The flaw is due to a stack overflow condition in the SNMP subsystem, which can be triggered by sending a specially crafted SNMP packet. This vulnerability affects all versions of SNMP and specific Cisco devices, including Meraki MS390 and Cisco Catalyst 9300 Series Switches running older software versions.
Exploitation of this vulnerability requires the attacker to have certain credentials. For a DoS attack, the attacker needs SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials. For arbitrary code execution as root, the attacker must possess SNMPv1 or v2c read-only community string or valid SNMPv3 user credentials along with administrative or privilege 15 credentials on the affected device.
Client Impact
Clients using affected Cisco devices may face operational disruptions due to potential DoS attacks or unauthorized access if the vulnerability is exploited. This could lead to data breaches, financial losses, and damage to reputation. Additionally, organizations may encounter regulatory compliance issues if sensitive data is compromised due to inadequate security measures.
From a compliance perspective, failure to address this vulnerability could result in audits or penalties, especially for industries with stringent data protection regulations. It is crucial for clients to assess their exposure to this vulnerability and take appropriate actions to mitigate risks.
Mitigations
To mitigate the risks associated with CVE-2025-20352, clients should consider the following actions:
- Update affected devices to Cisco IOS XE Software Release 17.15.4a to address the vulnerability.
- Restrict SNMP access to trusted users only, reducing the risk of unauthorized exploitation.
- Monitor systems using the "show snmp host" command to detect any suspicious activity.
- Disable affected OIDs on devices where applicable, keeping in mind that this may impact device management through SNMP.
- Regularly review and update SNMP configurations to ensure they align with security best practices.
Implementing these measures can significantly reduce the risk of exploitation and enhance overall network security. Clients are encouraged to remain vigilant and proactive in addressing potential vulnerabilities.
1898 & Co. Response
1898 & Co. is actively addressing the current threat landscape by offering specialized services to help clients mitigate emerging threats like CVE-2025-20352. Our team provides tailored security assessments and patch management solutions to ensure clients' systems are protected against known vulnerabilities.
We are updating our security protocols and practices to incorporate the latest threat intelligence and mitigation strategies. Our collaborative efforts with industry allies and government agencies enable us to stay ahead of evolving threats and provide clients with timely insights and recommendations.
Our ongoing research and threat intelligence gathering activities focus on identifying new vulnerabilities and attack vectors, allowing us to offer clients cutting-edge solutions. We have successfully assisted numerous clients in mitigating similar threats, demonstrating our commitment to delivering high-quality security services.