As many as 2 million Cisco devices are reportedly at risk due to an actively exploited zero-day vulnerability that can allow attackers to remotely crash these systems or execute arbitrary code. This vulnerability, identified as CVE-2025-20352, affects all supported versions of Cisco’s IOS and IOS XE, the operating systems that serve a range of the company’s networking hardware. Cisco has assigned a severity rating of 7.7 out of 10 to this flaw, indicating a critical security concern.
The Cisco Product Security Incident Response Team (PSIRT) alerted users on Wednesday to successful exploit attempts in the wild, specifically after local Administrator credentials were compromised. Businesses relying on Cisco equipment are strongly urged to update to the latest, patched software versions to mitigate this risk.
The vulnerability stems from a stack overflow issue within the IOS component that manages the Simple Network Management Protocol (SNMP). This protocol is commonly utilized by networking devices to monitor and manage networked systems. Exploitation occurs through the transmission of specially crafted SNMP packets, allowing attackers to initiate a denial-of-service attack or execute malicious code with root privileges, depending on the privilege level they have.
To carry out a remote code execution attack, an attacker needs access to the read-only community string, a form of SNMP authentication that is often included with devices, sometimes even unchanged by administrators. While the community strings can be modified, they are frequently subject to widespread knowledge within organizations. Hence, if an attacker gains knowledge of these strings and possesses the requisite privileges, they can execute remote code as a root user, significantly compromising the integrity of affected systems.
In light of this incident, organizations should take immediate action to safeguard their Cisco devices. Given the nature of the attack vector, it not only highlights the risks associated with default configurations but also underscores the importance of strict credential management and regular software updates.
For businesses, this vulnerability serves as a reminder of the critical need for robust cybersecurity policies. According to the MITRE ATT&CK framework, techniques such as initial access, privilege escalation, and execution may have been employed by attackers. Establishing a comprehensive security posture is vital in mitigating potential exploits stemming from such vulnerabilities, ensuring that organizations remain vigilant and prepared against evolving cyber threats.
