Vulnerability scanning is a pillar in any cyber security program, however understanding the results could make the difference between getting breached or not. One such vulnerability that has garnered attention in recent years is Cisco Smart Install (SMI). While designed to streamline the deployment of network devices, SMI can also pose significant risks if not properly managed, unfortunately many vulnerability scanners consider this an “Informational” level finding. In this article, we’ll explore the dangers of Cisco Smart Install, provide actionable insights for remediation, and discover how risky this setting really is.

Understanding Cisco Smart Install

Cisco Smart Install is a feature designed to simplify the process of deploying Cisco network devices by automating the installation of Cisco IOS software. It allows network administrators to remotely configure and provision new devices, saving time and effort during the setup process. In short, organizations with multiple locations often use SMI to ship off preconfigured devices for ease of use and to cut down on travel costs. However, this convenience comes with inherent security risks that organizations must be aware of.

The Risks

1. Unauthorized Access: One of the primary risks associated with Cisco Smart Install is the potential for unauthorized access to network devices. If left unsecured, attackers can exploit SMI vulnerabilities to gain unauthorized access to switches, routers, and other network infrastructure devices. Once compromised, attackers may eavesdrop on network traffic, intercept sensitive data, or even disrupt network operations.
2. Device Manipulation: In addition to unauthorized access, attackers can leverage SMI to manipulate network devices for malicious purposes. By exploiting vulnerabilities in the Smart Install protocol, attackers can reconfigure devices, install malicious firmware, or launch denial-of-service attacks, compromising the integrity and security of the network infrastructure.
3. Network-wide Exploitation: Perhaps most concerning is the potential for attackers to exploit SMI vulnerabilities to propagate across an entire network. Once attackers achieve an initial compromise, they can leverage SMI to deploy malware or exploit other vulnerabilities on connected devices, resulting in widespread network compromise and potential data breaches.

In Practice

There are many toolsets publicly available that specifically target this setting. These tools allows a malicious actor to easily download configuration files, execute commands, or even update configurations.
But let’s see what the most popular vulnerability scanner Nessus has to say about SMI.

Interesting, the scanner sets the severity to informational, but the description sounds quite sinister. Most organizations and security providers will stop simply at the heading on informational severity findings and not actually read the description. But maybe it really isn’t anything to worry about?

We’ll see for ourselves, let’s try leveraging this setting to see if we can pull configurations off the device. To do this we’ll use SIET (Smart Install Exploitation Tool), which can do a number of things such as test for SMI, obtain configurations, execute commands, or upload our own configuration.

You can review the syntax and features on the GitHub page but in this instance, we’re using the “-g” flag to pull the configuration and the “-i” flag to set the target IP address. As you can see it successfully downloaded the configuration file. Next, we’ll take a look inside the configuration file.

Naturally configuration information aids malicious attackers in understanding your environment and the ability to modify could have severe consequences. Additionally, attackers can obtain password hashes through these configuration files to elevate their privileges as well as move laterally within the network. Unfortunately, many organizations still utilize type 7 passwords which uses a weak reversible algorithm that makes decoding a breeze. Many online decoders exist such as PacketLife which can decode type 7 passwords on the fly, as shown below.

As demonstrated, this setting feels a lot more severe than a measly informational level.

Protecting Your Network

1. Disable Unused Features: If Cisco Smart Install is not required for your network deployment, consider disabling it altogether. By disabling unused features and protocols, you can reduce the attack surface and mitigate potential security risks. You can accomplish this with the command “no vstack”. Learn more by following the detailed information from the vendor here.
2. Secure Configuration: If SMI is necessary for your network infrastructure, ensure that it is configured securely. Implement access controls, authentication mechanisms, and encryption protocols to restrict unauthorized access and protect against exploitation. There is a mixture of options but enforcing access control lists either through infrastructure or VLAN access control lists (iACLs and VACLs) is a solid plan.  Additionally, enforcing strong encryption on all credentials is highly suggested.
3. Regular Security Audits: Conduct regular security audits and vulnerability assessments to identify and remediate potential weaknesses in your infrastructure. Ensure that your security partner or your internal teams are staying up to date on the latest attack trends. It’s imperative that you align your testing with offensive security experts to ensure quality testing is being performed.

Cisco Smart Install offers convenience and efficiency in deploying network devices, but it also introduces significant security risks if not properly safeguarded. At Breach Point, we specialize in helping organizations mitigate security risks and protect against threats. Contact us today to learn how we can help secure your assets and prevent potential vulnerabilities from being exploited.