CVE-2000-0493 in Simple Network Time Sync
Summary
by MITRE
Buffer overflow in Simple Network Time Sync (SMTS) daemon allows remote attackers to cause a denial of service and possibly execute arbitrary commands via a long string.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2000-0493 represents a critical buffer overflow flaw within the Simple Network Time Sync daemon, a component designed to synchronize system clocks across networked devices. This daemon operates as a network service that listens for time synchronization requests and responds accordingly, making it a potential target for remote exploitation. The flaw manifests when the daemon receives a malformed time synchronization request containing an excessively long string that exceeds the allocated buffer space in memory. This condition creates a classic buffer overflow scenario where adjacent memory locations become overwritten, potentially corrupting program execution flow and system stability. The vulnerability is categorized under CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1499.004 for network denial of service attacks.
The technical implementation of this vulnerability exploits the daemon's insufficient input validation mechanisms when processing time synchronization requests. When a remote attacker sends a specially crafted packet containing an oversized string parameter, the daemon fails to properly bounds-check the input before copying it into a fixed-size buffer. This allows the attacker to overwrite critical memory segments including return addresses, function pointers, or other control data structures within the program's execution context. The overflow can cause the daemon to crash and terminate unexpectedly, resulting in immediate denial of service for legitimate time synchronization requests. In certain configurations where the daemon runs with elevated privileges, the overflow may also provide opportunities for arbitrary code execution, allowing attackers to gain unauthorized access to the compromised system and potentially escalate their privileges.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader security implications for networked environments. Organizations relying on time synchronization services for critical operations such as log correlation, authentication mechanisms, or distributed system coordination face significant risks when affected by this flaw. The remote nature of the attack means that adversaries can exploit the vulnerability from any network location without requiring physical access or prior authentication. This characteristic makes the vulnerability particularly dangerous in environments where time synchronization services are exposed to untrusted networks or internet-facing systems. The potential for remote code execution in vulnerable configurations can lead to complete system compromise, data exfiltration, or establishment of persistent backdoors within affected networks. Network administrators must consider the cascading effects of such vulnerabilities, as compromised time synchronization services can disrupt security logging, authentication systems, and other time-dependent security controls.
Mitigation strategies for CVE-2000-0493 should focus on immediate patching of affected systems and implementation of network-level protections. Organizations should prioritize applying vendor-specific security patches or upgrading to versions that address the buffer overflow condition in the SMTS daemon. Network segmentation and access control measures should be implemented to restrict access to time synchronization services, limiting exposure to untrusted networks. Firewall rules should be configured to restrict access to time synchronization ports such as UDP port 37 or TCP port 123, depending on the specific implementation. Additional defensive measures include implementing intrusion detection systems to monitor for suspicious time synchronization traffic patterns and deploying application-level firewalls or proxy services to validate input parameters before they reach the daemon. System hardening practices such as running the daemon with minimal required privileges, implementing address space layout randomization, and enabling stack canaries can provide additional layers of protection against exploitation attempts. Regular vulnerability assessments and security audits should be conducted to identify and remediate similar buffer overflow vulnerabilities across the entire network infrastructure.