CVE-2008-1525 in ZyNOS
Summary
by MITRE
The default SNMP configuration on ZyXEL Prestige routers, including P-660 and P-661 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), has a Trusted Host value of 0.0.0.0, which allows remote attackers to send SNMP requests from any source IP address.
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Analysis
by VulDB Data Team • 09/20/2018
The vulnerability identified as CVE-2008-1525 represents a critical misconfiguration in the SNMP implementation of ZyXEL Prestige routers, specifically affecting models P-660 and P-661 with firmware versions ranging from 3.40(AGD.2) through 3.40(AHQ.3). This issue stems from the default SNMP configuration where the Trusted Host value is set to 0.0.0.0, a configuration that fundamentally undermines network security by allowing unrestricted access to SNMP services from any remote IP address. The Trusted Host value in SNMP represents a security mechanism that typically defines which IP addresses or networks are authorized to communicate with the SNMP agent, and setting this value to 0.0.0.0 effectively removes all such restrictions, creating an open door for malicious actors.
This vulnerability operates at the network infrastructure level and directly impacts the router's ability to maintain secure communication channels. The SNMP protocol itself is designed for network management and monitoring purposes, but when improperly configured, it becomes a vector for unauthorized access and information gathering. The flaw essentially transforms the router's SNMP service from a legitimate management tool into a potential entry point for attackers seeking to exploit the device. According to CWE-284, this represents an improper access control vulnerability where the system fails to properly restrict access to network services, and the configuration error falls under CWE-706, which deals with use of incorrect defaults.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it enables attackers to perform a wide range of malicious activities including but not limited to network reconnaissance, service enumeration, and potentially system compromise. Attackers can leverage this vulnerability to gather sensitive information about the network topology, device configurations, and operational parameters without requiring authentication. This aligns with ATT&CK technique T1018 for Valid Accounts and T1046 for Network Service Scanning, as the vulnerability allows adversaries to discover network services and potentially escalate privileges through unauthorized access to management interfaces. The vulnerability also exposes the network to potential man-in-the-middle attacks where attackers can manipulate SNMP communications to gain further network access.
Mitigation strategies for this vulnerability must address the fundamental configuration error that allows unrestricted SNMP access. Network administrators should immediately update the Trusted Host value to restrict access to specific authorized IP addresses or networks, typically requiring a firmware update or manual configuration change. The recommended approach involves implementing proper access control lists that limit SNMP access to trusted management stations only. Additionally, organizations should consider disabling SNMP entirely if it is not required for network management purposes, as this eliminates the attack surface entirely. According to industry best practices and security frameworks, this vulnerability demonstrates the critical importance of secure configuration management and the principle of least privilege in network security. Regular security audits and vulnerability assessments should include verification of SNMP configurations to prevent similar issues from occurring in other network devices. The vulnerability also underscores the necessity of keeping network equipment firmware updated and following security guidelines provided by vendors to ensure that default configurations do not introduce security risks.