Zero-Day Alert: Cisco IOS

Summary

Cisco has issued a warning about a zero-day vulnerability, identified as CVE-2023-20109, impacting IOS and IOS XE software. This medium-severity security flaw is associated with the Group Domain of Interpretation (GDOI) and G-IKEv2 protocols used in the GET VPN feature. The vulnerability, discovered by X. B. of the Cisco Advanced Security Initiatives Group (ASIG), can potentially allow attackers to execute arbitrary code or cause system crashes. While exploitation requires administrative control of a key server or a group member, attackers have already started targeting it in attacks.

Impact Assessment

CVE-2023-20109, although considered medium-severity, has the potential for significant impact. Attackers with admin control over a key server or group member can exploit the vulnerability to execute arbitrary code, gain full control of the affected system, or cause a denial of service (DoS) condition.

What It Means for You

This vulnerability highlights the need for stringent access control and security measures within your network infrastructure. While successful exploitation depends on attackers already having infiltrated the environment, the consequences can be severe, including unauthorized access, data breaches, and service disruption.

Remediation

Cisco recommends that affected customers upgrade to a fixed software release to mitigate the CVE-2023-20109 vulnerability. It is essential for organizations to take the following actions:

1. Patch Management: Apply the recommended software patches promptly to all affected devices running IOS or IOS XE software with GDOI or G-IKEv2 protocol enabled.
2. Access Control: Review and strengthen access control policies to prevent unauthorized administrative access to key servers and group members.
3. Network Segmentation: Implement network segmentation to limit the lateral movement of attackers within the network.
4. Incident Response: Enhance incident response plans to include procedures for addressing vulnerabilities and potential breaches in the GET VPN feature.
5. Monitoring and Detection: Invest in network monitoring and threat detection solutions to identify and respond to unauthorized activities promptly.

Business Implications

Failure to address CVE-2023-20109 can result in security breaches, data compromise, and operational disruptions. Additionally, it highlights the need for proactive security measures and continuous monitoring, given that attackers have already targeted this vulnerability.

Access Point Technology’s Recommendation

1. Immediate Patching: Prioritize the installation of recommended software patches on affected Cisco devices.
2. Access Control Review: Conduct a thorough review of access control policies and configurations, ensuring that only authorized personnel have administrative control.
3. Security Awareness: Educate employees about the importance of security practices and reporting any suspicious activity.
4. Incident Response Enhancement: Update incident response plans to include specific actions for addressing this vulnerability and similar threats.
5. Ongoing Monitoring: Implement continuous network monitoring to detect and respond to unauthorized access or suspicious behavior.

By following these recommendations, businesses can effectively mitigate the risks associated with CVE-2023-20109 and enhance their overall network security posture.

Associated Bulletins

https://www.bleepingcomputer.com/news/security/cisco-urges-admins-to-fix-ios-software-zero-day-exploited-in-attacks/

https://nvd.nist.gov/vuln/detail/CVE-2023-20109  

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-getvpn-rce-g8qR68sx