CVE-2021-43044 in Unitrends Backup Appliance
Summary
by MITRE • 12/06/2021
An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The SNMP daemon was configured with a weak default community.
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Analysis
by VulDB Data Team • 12/09/2021
The vulnerability identified as CVE-2021-43044 affects the Kaseya Unitrends Backup Appliance version prior to 10.5.5, representing a significant security flaw in the appliance's network monitoring configuration. This issue stems from the SNMP daemon being configured with a default community string that lacks sufficient cryptographic strength, creating an exploitable weakness in the system's network management infrastructure. The problem is particularly concerning as it affects backup appliances that are critical components in enterprise data protection environments, where unauthorized access could compromise entire backup operations and sensitive data repositories.
The technical flaw manifests in the SNMP daemon's default configuration where a predictable and weak community string is implemented, allowing unauthorized network management operations to be performed without proper authentication. This weak default community string enables attackers to perform various SNMP operations including reading system information, modifying configurations, and potentially gaining further access to the underlying system. The vulnerability falls under CWE-320, which specifically addresses the use of hardcoded credentials, and represents a classic example of poor default security configuration that persists across multiple system deployments. The weakness is exacerbated by the fact that SNMP community strings serve as the primary authentication mechanism for network management operations, making this a critical vector for unauthorized access to network infrastructure.
The operational impact of this vulnerability extends beyond simple network monitoring access, as the compromised appliance could provide attackers with comprehensive visibility into the backup environment and potentially enable them to manipulate backup operations, access sensitive data, or disrupt critical backup processes. Organizations utilizing Kaseya Unitrends Backup Appliances may find their data protection infrastructure compromised, potentially leading to data loss, unauthorized access to backup repositories, and disruption of business continuity operations. The vulnerability aligns with ATT&CK technique T1078.004 which covers legitimate credentials, and represents a significant risk to enterprise security posture, particularly in environments where backup systems are not adequately segmented or monitored. Attackers could leverage this weakness to conduct reconnaissance, escalate privileges, or establish persistence within the network infrastructure.
Mitigation strategies for CVE-2021-43044 should prioritize immediate configuration updates to replace the weak default SNMP community string with a strong, randomly generated value that meets current security standards. Organizations must ensure that SNMP community strings are properly configured with appropriate access controls and that the appliance is updated to version 10.5.5 or later where this vulnerability has been addressed. Network segmentation should be implemented to limit access to the appliance's SNMP ports, and regular security audits should verify that default configurations have been properly modified. Additionally, implementing network monitoring solutions to detect unauthorized SNMP access attempts and establishing proper change management procedures for network management configurations will help prevent similar issues from occurring in other system components. The remediation process should also include verifying that SNMPv3 is enabled where possible, as it provides superior authentication and encryption compared to the vulnerable SNMPv1 and SNMPv2c implementations.