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Cisco Vulnerability (CVE-2025-20352) Allows Remote Code Execution
Table of Contents
Overview
Cisco has disclosed a critical vulnerability, designated CVE-2025-20352, affecting all supported versions of Cisco IOS and Cisco IOS XE software. These operating systems power a broad range of Cisco networking devices. The vulnerability allows attackers too potentially launch denial-of-service attacks or, with higher privileges, gain remote code execution (RCE) with root-level access.
The vulnerability has a Common Vulnerability Scoring System (CVSS) severity rating of 7.7 out of 10, indicating a significant risk. Cisco issued an advisory on Wednesday, September 25, 2024, urging customers to upgrade to a fixed software release.
How the vulnerability Works
The root cause of the vulnerability is a stack overflow bug within the IOS component responsible for handling the simple Network Management Protocol (SNMP). SNMP is a standard protocol used by network devices to collect and manage information. Attackers exploit this flaw by sending specially crafted SNMP packets to vulnerable devices.
To achieve remote code execution, an attacker requires a read-only SNMP community string - a form of authentication for accessing managed devices. SNMP community strings are often pre-configured on devices or, even when changed, may be widely known within an institution. The attacker also needs existing privileges on the system.Successful exploitation grants the attacker root-level access, allowing them to execute arbitrary code.
Real-World Exploitation
Cisco’s Product Security Incident Response Team (PSIRT) confirmed that the vulnerability is already being actively exploited in the wild. the exploitation occurred after local administrator credentials were compromised, highlighting the importance of strong credential management practices. This confirms the vulnerability is not merely theoretical but poses an immediate threat to network security.
Affected Products
All supported versions of Cisco IOS and Cisco IOS XE are affected by this vulnerability.This includes a wide range of Cisco networking equipment, such as routers, switches, and wireless controllers. A comprehensive list of affected products and available software updates can be found in the official Cisco Security Advisory.
Mitigation and Remediation
Cisco strongly recommends that all customers upgrade to a fixed software release to address this vulnerability. The advisory provides links to the appropriate software updates for affected devices. In addition to upgrading,organizations should review their SNMP configuration and ensure strong community string security. Consider disabling SNMP if it is not essential for network operations.
Further mitigation steps include:
- Strong Authentication: Implement robust authentication mechanisms for SNMP access.
- Access Control Lists (ACLs): Restrict SNMP access to only authorized devices and networks.
- Regular Audits: Conduct regular security audits to identify and address potential vulnerabilities.
- Network segmentation: Isolate critical network segments to limit the impact of a potential breach.
Timeline
- September 25, 2024: Cisco publicly discloses CVE-2025-20352 and releases security advisory.
- Ongoing: PSIRT confirms active exploitation in the wild.
- Future: Continued monitoring for exploitation attempts and development of further mitigation strategies.
