In the realm of cybersecurity, it is crucial to stay informed about the latest threats and vulnerabilities that could potentially impact your organization. This threat advisory focuses on multiple vulnerabilities discovered in Cisco Small Business routers, which can allow malicious actors to execute arbitrary code with root privileges and cause denial-of-service (DoS) conditions. These vulnerabilities pose a significant risk as they can lead to unauthorized access, data breaches, and disruption of business operations. As a cybersecurity company dedicated to protecting your organization's digital assets, Enterprotect provides valuable insights and recommendations to mitigate these vulnerabilities effectively.

What is the Threat?

The threat involves multiple vulnerabilities in the web management interface of Cisco Small Business routers. Of the nine vulnerabilities discovered, four are rated 9.8 out of 10 on the Common Vulnerability Scoring System (CVSS). These vulnerabilities include:

• CVE-2023-20159 (CVSS score: 9.8): Cisco Small Business Series Switches Stack Buffer Overflow Vulnerability

• CVE-2023-20160 (CVSS score: 9.8): Cisco Small Business Series Switches Unauthenticated BSS Buffer Overflow Vulnerability

• CVE-2023-20161 (CVSS score: 9.8): Cisco Small Business Series Switches Unauthenticated Stack Buffer Overflow Vulnerability

• CVE-2023-20189 (CVSS score: 9.8): Cisco Small Business Series Switches Unauthenticated Stack Buffer Overflow Vulnerability

• CVE-2023-20024 (CVSS score: 8.6): Cisco Small Business Series Switches Unauthenticated Heap Buffer Overflow Vulnerability

• CVE-2023-20156 (CVSS score: 8.6): Cisco Small Business Series Switches Unauthenticated Heap Buffer Overflow Vulnerability

• CVE-2023-20157 (CVSS score: 8.6): Cisco Small Business Series Switches Unauthenticated Heap Buffer Overflow Vulnerability

• CVE-2023-20158 (CVSS score: 8.6): Cisco Small Business Series Switches Unauthenticated Denial-of-Service Vulnerability

• CVE-2023-20162 (CVSS score: 7.5): Cisco Small Business Series Switches Unauthenticated Configuration Reading Vulnerability

These vulnerabilities involve improper input validation, command injection, and arbitrary code execution. By sending crafted requests to targeted routers, attackers can exploit these vulnerabilities to execute arbitrary code with elevated privileges. The consequences may include compromising the router, unauthorized access to sensitive information, and further network infiltration. The vulnerabilities affect various Cisco Small Business Switches when running a vulnerable firmware release, including the 250 Series Smart Switches, 350 Series Managed Switches, 350X Series Stackable Managed Switches, 550X Series Stackable Managed Switches, Business 250 Series Smart Switches, Business 350 Series Managed Switches, Small Business 200 Series Smart Switches, Small Business 300 Series Managed Switches, and Small Business 500 Series Stackable Managed Switches.

Why is it Noteworthy?

Cisco Small Business routers are widely used by businesses globally, making them an attractive target for threat actors. The ability to remotely execute arbitrary code with elevated privileges presents a significant risk, potentially leading to unauthorized access and compromise of sensitive information. Moreover, compromised routers can serve as gateways for further network infiltration and malicious activities. The availability of proof-of-concept exploit code for these security flaws, as disclosed by the Cisco Product Security Incident Response Team (PSIRT), increases the likelihood of active exploitation by motivated threat actors. Addressing these vulnerabilities promptly is crucial to prevent potential data breaches, financial losses, and reputational damage.

What is the Exposure or Risk?

Upon successful exploitation, an attacker can execute arbitrary code with elevated privileges, potentially leading to unauthorized access to the routers. This unauthorized access enables threat actors to intercept and manipulate network traffic, compromise sensitive information, and gain a foothold within the organization's network. Additionally, compromised routers can serve as launching pads for attackers to pivot into other parts of the network, escalate their privileges, and target critical systems or data repositories. Consequently, the risks associated with unauthorized access and potential network compromise raise concerns for organizations relying heavily on Cisco Small Business routers, such as small and medium-sized businesses (SMBs), branch offices, service providers, government organizations, and enterprises. To mitigate these risks effectively, timely addressing of these vulnerabilities is essential.

What are the Recommendations?

Enterprotect provides the following recommendations to ensure the security of your systems:

1. Apply security patch updates: Cisco has released security updates to address these vulnerabilities. It is crucial for organizations using Cisco Small Business routers to promptly apply the latest firmware updates to protect their devices from potential exploitation.

2. Implement network segmentation: Segmenting the network and restricting access to critical devices, including routers, can help contain potential compromises and limit the impact of an attack. By dividing the network into isolated segments, organizations can control and monitor access more effectively, reducing the risk of lateral movement by attackers.

3. Enable strong authentication: Ensure the enforcement of strong authentication mechanisms, such as two-factor authentication (2FA), for router access. Strong authentication adds an additional layer of security and mitigates the risk of unauthorized access attempts.

4. Regular security assessments: Implement network vulnerability management and conduct regular vulnerability assessments on network infrastructure, including routers. By identifying and remediating potential weaknesses proactively, organizations can enhance their overall security posture and minimize the risk of successful attacks.

Incorporating these recommendations into your organization's cybersecurity practices will help mitigate the risks associated with these vulnerabilities and enhance your overall security posture.

References

For more detailed information about the recommendations provided in this advisory, please refer to the following sources:

1. Cisco Security Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg-web-multi-S9g4Nkgv

2. The Hacker News: https://thehackernews.com/2023/05/critical-flaws-in-cisco-small-business.html

3. Bleeping Computer: https://www.bleepingcomputer.com/news/security/cisco-warns-of-critical-switch-bugs-with-public-exploit-code/

By following the recommendations outlined in this threat advisory, organizations can proactively protect their network infrastructure, mitigate potential vulnerabilities, and safeguard their sensitive information from unauthorized access and compromise. Stay vigilant and ensure the security of your organization's systems and data.