CVE-2016-1452 in ASR 5000
Summary
by MITRE
Cisco ASR 5000 devices with software 18.3 through 20.0.0 allow remote attackers to make configuration changes over SNMP by leveraging knowledge of the read-write community, aka Bug ID CSCuz29526.
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Analysis
by VulDB Data Team • 09/05/2022
The vulnerability CVE-2016-1452 affects Cisco ASR 5000 series devices running software versions 18.3 through 20.0.0, representing a critical security flaw that enables remote attackers to execute unauthorized configuration modifications via SNMP protocols. This vulnerability resides within the network infrastructure equipment that serves as a core component in carrier-grade routing and switching environments, making it particularly dangerous due to the critical nature of the affected devices. The flaw specifically exploits the lack of proper authentication and authorization controls within the SNMP implementation, allowing attackers with knowledge of the read-write SNMP community string to manipulate device configurations remotely. This represents a significant compromise of network security posture since ASR 5000 devices typically operate in sensitive telecommunications environments where configuration integrity is paramount for network stability and security.
The technical implementation of this vulnerability stems from inadequate access control mechanisms within the SNMP service of the affected Cisco devices. When an attacker possesses the correct read-write SNMP community string, they can leverage this knowledge to send crafted SNMP SET requests that modify various configuration parameters within the device. This flaw falls under the category of insufficient authentication as defined by CWE-287, where the system fails to properly verify the identity of users attempting to perform administrative operations. The vulnerability demonstrates poor privilege separation and authorization enforcement, allowing low-privilege SNMP access to escalate to full configuration modification capabilities. The attack vector is particularly concerning because it requires minimal attack surface exposure since SNMP is commonly enabled for network monitoring purposes, making the read-write community string a potential attack target.
The operational impact of this vulnerability extends beyond simple configuration changes, as it can lead to complete network disruption, unauthorized access to sensitive data, and potential compromise of the entire telecommunications infrastructure. Attackers could modify routing tables, disable security features, change administrative credentials, or redirect traffic through maliciously configured network paths. This vulnerability directly impacts the CIA triad by compromising both confidentiality and integrity, as unauthorized modifications can expose sensitive network information and corrupt the device's operational state. The ASR 5000 devices operate in carrier-grade environments where network stability is critical, and any unauthorized configuration changes can result in service outages affecting numerous end users. This vulnerability aligns with ATT&CK technique T1078.004 for valid accounts and T1566.001 for spearphishing via social engineering, as it exploits legitimate administrative access mechanisms that are often poorly secured in production environments.
Mitigation strategies for CVE-2016-1452 should prioritize immediate implementation of network segmentation and access control measures to restrict SNMP access to trusted administrative networks only. Organizations must ensure that SNMP community strings are properly configured with strong, unique credentials and that read-write access is restricted to essential personnel only. The implementation of network access control lists and firewall rules should limit SNMP traffic to specific administrative IP addresses and ports. Cisco recommends upgrading to software versions that contain patches addressing this vulnerability, as the company has released security updates to resolve the authentication bypass issue. Additional mitigations include disabling SNMPv1 and SNMPv2c where possible, implementing SNMPv3 with strong authentication and encryption, and conducting regular security audits to identify and remediate any unauthorized SNMP access. Network monitoring should be enhanced to detect anomalous SNMP traffic patterns that may indicate exploitation attempts, and regular vulnerability scanning should be performed to identify devices running vulnerable software versions. The vulnerability also highlights the importance of implementing the principle of least privilege and following security best practices for network service configuration as outlined in various cybersecurity frameworks including NIST SP 800-53 and ISO 27001 standards.