CVE-1999-0516 in SNMP Server
Summary
by MITRE
An SNMP community name is guessable.
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Analysis
by VulDB Data Team • 06/23/2021
The vulnerability described in CVE-1999-0516 represents a fundamental security weakness in network management protocols that has persisted as a critical concern for decades. This issue specifically targets the Simple Network Management Protocol which relies on community strings as a form of authentication mechanism. The vulnerability arises when network administrators configure SNMP services with predictable or default community names such as public or private, making these access credentials easily guessable by malicious actors. The problem stems from poor security configuration practices where system administrators fail to implement strong, unique community strings that would resist brute force or dictionary attacks.
The technical flaw underlying this vulnerability can be categorized as a weak authentication mechanism that violates established security principles. According to CWE-310, this represents a weakness in cryptographic strength or key generation where the authentication tokens used by SNMP are insufficiently complex to resist automated guessing attacks. The vulnerability creates a direct path for unauthorized access to network device management interfaces, allowing attackers to extract sensitive configuration data, monitor network traffic, and potentially execute commands on managed devices. This weakness operates at the application layer of network protocols and specifically affects the network management subsystems that rely on SNMP for device monitoring and control.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it provides attackers with comprehensive access to network infrastructure management capabilities. Organizations running SNMP services with guessable community names face significant risks including unauthorized network reconnaissance, configuration modifications, and potential network compromise. The vulnerability enables attackers to perform actions consistent with the ATT&CK technique T1046 for network service scanning and T1078 for valid accounts usage. When combined with other network reconnaissance activities, this vulnerability can serve as a stepping stone for more sophisticated attacks, allowing threat actors to establish persistent access to network management systems and potentially escalate privileges to gain broader network control.
Mitigation strategies for CVE-1999-0516 require immediate implementation of strong authentication practices and network security configurations. Organizations should replace default or predictable community strings with complex, randomly generated passwords that meet minimum length requirements of at least 15 characters with mixed character sets. Network administrators must implement SNMPv3 which provides strong authentication and encryption mechanisms, eliminating the reliance on community strings entirely. Additionally, proper network segmentation should be implemented to isolate SNMP traffic from critical network segments, and access controls should be configured to limit SNMP access to authorized management stations only. Regular security audits should verify that SNMP configurations do not contain weak community strings and that all network devices have been updated to use more secure authentication methods. The implementation of these measures directly addresses the root cause of the vulnerability while aligning with industry standards such as NIST SP 800-53 and ISO 27001 security requirements for network management system protection.