CVE-2016-1473 in Small Business 220
Summary
by MITRE
Cisco Small Business 220 devices with firmware before 1.0.1.1 have a hardcoded SNMP community, which allows remote attackers to read or modify SNMP objects by leveraging knowledge of this community, aka Bug ID CSCuz76216.
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Analysis
by VulDB Data Team • 09/14/2022
The vulnerability CVE-2016-1473 affects Cisco Small Business 220 series network devices where the firmware versions prior to 1.0.1.1 contain a hardcoded SNMP community string. This represents a critical security flaw that fundamentally undermines the device's network management security posture. The issue stems from the improper implementation of authentication mechanisms within the device's SNMP configuration, where a default community string is embedded in the firmware code rather than being dynamically generated or properly secured. This hardcoded community string creates a persistent backdoor that remains unchanged across device deployments and firmware updates, making it an attractive target for attackers seeking unauthorized network access.
The technical exploitation of this vulnerability occurs through standard SNMP protocols that are commonly enabled on network devices for monitoring and management purposes. Attackers who discover the hardcoded community string can remotely access the device's SNMP MIB (Management Information Base) and perform unauthorized read or write operations on network configuration parameters. This includes accessing sensitive information such as device configurations, network topology details, user credentials stored in memory, and operational parameters that could reveal the internal network structure. The vulnerability aligns with CWE-798, which specifically addresses the use of hard-coded credentials, and represents a classic example of poor secure coding practices in embedded network devices.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to modify network configurations and potentially establish persistent access points within the network infrastructure. An attacker could leverage this access to reconfigure network settings, disable security features, redirect traffic through malicious endpoints, or use the device as a pivot point for further attacks against internal network segments. This vulnerability particularly affects small business networks where network administrators may not be fully aware of the device's SNMP configuration or may not have implemented proper network segmentation to limit the potential damage from such an attack. The attack surface is significantly expanded due to the default nature of the vulnerability and the widespread deployment of these devices in unsecured environments.
Mitigation strategies for CVE-2016-1473 require immediate firmware updates to version 1.0.1.1 or later, which address the hardcoded community string issue by implementing proper authentication mechanisms. Network administrators should also disable SNMP if it is not required for network management operations, as this eliminates the attack surface entirely. Additionally, implementing network segmentation and access control lists can limit the impact of successful exploitation by restricting the network access that an attacker could gain from compromising a single device. Organizations should conduct comprehensive network audits to identify all affected devices and ensure that SNMP community strings are properly configured with strong, unique values rather than default or hardcoded credentials. The vulnerability demonstrates the importance of following security best practices such as those outlined in the NIST Cybersecurity Framework and aligns with ATT&CK technique T1082 for system information discovery and T1078 for valid accounts, as attackers can leverage this vulnerability to establish persistent access and gather system information.