CVE-2023-20186 is a vulnerability in the AAA feature of Cisco IOS and IOS XE software where improper authorization checks occur during Secure Copy Protocol (SCP) command processing. Specifically, the AAA command authorization mechanism fails to correctly validate SCP commands, allowing an authenticated remote attacker with level 15 privileges to bypass command authorization controls. By exploiting this flaw, the attacker can use SCP to connect remotely to an affected device and copy files to or from its file system without proper authorization. This can lead to unauthorized disclosure of sensitive configuration files or unauthorized modification of device configurations, potentially disrupting network operations or enabling further attacks. The vulnerability affects numerous Cisco IOS versions, spanning from older 12.2(58)SE releases to recent 15.x releases, indicating a broad impact across many deployed devices. Exploitation requires valid credentials with high privilege (level 15), no user interaction, and can be performed remotely over the network. The CVSS v3.1 score is 8.0 (high), reflecting the critical impact on confidentiality, integrity, and availability, combined with the requirement for high privileges and high attack complexity. No public exploits or active exploitation have been reported, but the vulnerability poses a significant risk due to the critical role of Cisco IOS devices in enterprise and service provider networks.

For European organizations, this vulnerability represents a serious risk to network infrastructure security. Cisco IOS devices are widely used in enterprise networks, telecommunications providers, and critical infrastructure across Europe. Successful exploitation could lead to unauthorized access to sensitive network configurations, enabling attackers to disrupt services, intercept or redirect traffic, or establish persistent footholds. The ability to copy files to and from devices could facilitate data exfiltration or deployment of malicious configurations. Given the broad range of affected IOS versions, many legacy and current devices in use may be vulnerable. The impact extends to confidentiality, integrity, and availability of network operations, potentially affecting business continuity and regulatory compliance, especially under GDPR and NIS Directive requirements. The requirement for valid credentials limits exploitation to insider threats or attackers who have compromised credentials, but the high privileges needed mean that once exploited, the attacker gains full control over device configurations. This elevates the threat to critical infrastructure and large enterprises with complex Cisco deployments.

European organizations should implement the following specific mitigations: 1) Immediately identify and inventory all Cisco IOS and IOS XE devices running affected versions using network management tools and Cisco’s advisories. 2) Apply Cisco’s security patches or software updates that address CVE-2023-20186 as soon as they become available. 3) Restrict SCP access to trusted management networks and limit access to devices only to authorized administrators with strict credential management and multi-factor authentication. 4) Monitor SCP usage and AAA logs for anomalous file transfer activities or unauthorized access attempts. 5) Implement network segmentation to isolate critical network devices from general user networks to reduce exposure. 6) Regularly audit user privileges to ensure that only necessary personnel have level 15 access. 7) Employ strong credential hygiene, including regular password changes and detection of credential compromise. 8) Consider disabling SCP if not required or replacing it with more secure file transfer mechanisms with enhanced authorization controls. 9) Use Cisco’s recommended configuration best practices for AAA and SCP to minimize attack surface. 10) Prepare incident response plans specifically addressing potential device compromise scenarios.