CVE-2017-6462 in ntp
Summary
by MITRE
Buffer overflow in the legacy Datum Programmable Time Server (DPTS) refclock driver in NTP before 4.2.8p10 and 4.3.x before 4.3.94 allows local users to have unspecified impact via a crafted /dev/datum device.
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Analysis
by VulDB Data Team • 09/14/2020
The vulnerability identified as CVE-2017-6462 represents a critical buffer overflow flaw within the legacy Datum Programmable Time Server DPTS refclock driver implementation in the Network Time Protocol daemon. This issue affects NTP versions prior to 4.2.8p10 and 4.3.x prior to 4.3.94, creating a significant security risk for systems relying on precise time synchronization through this specific hardware interface. The vulnerability specifically targets the handling of input data from the /dev/datum device, which serves as the communication interface between the NTP daemon and the Datum time server hardware.
The technical exploitation of this buffer overflow occurs when the NTP daemon processes data from the /dev/datum device without proper bounds checking or input validation. This flaw allows a local attacker with access to the device to craft malicious input data that exceeds the allocated buffer space, potentially leading to memory corruption and arbitrary code execution within the NTP process context. The vulnerability falls under CWE-121, which describes classic buffer overflow conditions where insufficient bounds checking permits access beyond the boundaries of allocated memory regions. The attack vector requires local system access since the /dev/datum device is typically accessible only to privileged users or processes.
The operational impact of this vulnerability extends beyond simple privilege escalation as it can enable attackers to compromise the time synchronization services that many critical infrastructure components depend upon. When exploited successfully, the buffer overflow could allow an attacker to gain control over the NTP daemon process, potentially leading to time manipulation attacks, denial of service conditions, or further privilege escalation within the system. The unspecified impact mentioned in the CVE description suggests that the consequences could vary depending on the execution environment and the specific memory layout of the target system, making this vulnerability particularly dangerous in production environments where NTP serves as a foundational service.
Mitigation strategies for CVE-2017-6462 primarily focus on immediate patching of affected NTP versions to the recommended secure releases. System administrators should prioritize upgrading to NTP 4.2.8p10 or 4.3.94 and later versions that contain the necessary fixes for this buffer overflow vulnerability. Additionally, implementing proper access controls and device permissions for /dev/datum can limit local user access to the device, reducing the attack surface. The mitigation approach aligns with ATT&CK technique T1068, which addresses local privilege escalation through software vulnerabilities, and emphasizes the importance of maintaining up-to-date system components as a fundamental security control. Organizations should also consider disabling unused refclock drivers and implementing monitoring for suspicious device access patterns to detect potential exploitation attempts.