CVE-2006-6305 in net-snmp
Summary
by MITRE
Unspecified vulnerability in Net-SNMP 5.3 before 5.3.0.1, when configured using the rocommunity or rouser snmpd.conf tokens, causes Net-SNMP to grant write access to users or communities that only have read-only access.
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Analysis
by VulDB Data Team • 03/13/2021
The vulnerability described in CVE-2006-6305 represents a critical access control flaw within the Net-SNMP implementation that fundamentally undermines the security model of the Simple Network Management Protocol. This issue affects versions of Net-SNMP prior to 5.3.0.1 and specifically manifests when the daemon is configured using either the rocommunity or rouser directives in the snmpd.conf configuration file. The core problem lies in the improper handling of access permissions where read-only configured users or communities are inadvertently granted write privileges, creating a privilege escalation scenario that violates fundamental security principles.
The technical implementation of this vulnerability stems from a flaw in the SNMP access control list processing mechanism within Net-SNMP's daemon component. When administrators configure read-only access using the rocommunity or rouser tokens, the system should enforce strict read-only permissions for those specific entities. However, due to a code defect in the permission parsing and enforcement logic, the system fails to properly distinguish between read-only and read-write access levels. This misconfiguration allows authenticated users who should only have read capabilities to perform write operations on managed devices, effectively bypassing the intended security boundaries.
From an operational impact perspective, this vulnerability creates significant risks for network management systems that rely on Net-SNMP for monitoring and control functions. Attackers who can gain access to a read-only SNMP community string or user account can exploit this flaw to execute write operations, potentially leading to unauthorized configuration changes, data manipulation, or service disruption. The vulnerability particularly affects enterprise networks where SNMP is extensively used for device monitoring, as it allows attackers to escalate privileges without requiring additional authentication mechanisms or elevated access rights. This issue directly violates the principle of least privilege and can result in comprehensive system compromise when combined with other network reconnaissance activities.
The flaw aligns with CWE-284 Access Control Issues, specifically addressing improper access control mechanisms where the system fails to properly enforce access restrictions. This vulnerability also maps to ATT&CK technique T1078 Valid Accounts, as it allows attackers to leverage legitimate read-only accounts to gain elevated privileges through improper access control implementation. Organizations using Net-SNMP in production environments should consider this vulnerability as a high-priority remediation item, particularly in environments where SNMP is used for both monitoring and configuration management functions. The recommended mitigation involves upgrading to Net-SNMP version 5.3.0.1 or later, which contains the necessary patches to properly enforce access control boundaries. Additionally, network administrators should review existing SNMP configurations to ensure that read-only communities and users are properly isolated from write-capable entities, and implement network segmentation to limit SNMP access to authorized management systems only.