CVE-2019-6444 in NTPsec
Summary
by MITRE
An issue was discovered in NTPsec before 1.1.3. process_control() in ntp_control.c has a stack-based buffer over-read because attacker-controlled data is dereferenced by ntohl() in ntpd.
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2019-6444 represents a critical stack-based buffer over-read flaw within the NTPsec network time protocol implementation. This issue affects versions prior to 1.1.3 and stems from improper handling of attacker-controlled data within the process_control() function located in ntp_control.c. The vulnerability manifests when the ntpd daemon processes control messages, specifically where attacker-provided data undergoes ntohl() conversion without adequate bounds checking. This flaw creates a condition where the application reads beyond the allocated buffer boundaries, potentially exposing sensitive memory contents or enabling arbitrary code execution.
The technical nature of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, though specifically classified as an over-read condition rather than a traditional overflow. The flaw occurs in the network time protocol daemon's control message processing pipeline where network packets containing attacker-controlled data are parsed and converted using the ntohl() function. This function converts network byte order to host byte order, but without proper validation of the data length or buffer boundaries, the application can access memory locations beyond the intended buffer limits. The operational impact is significant as this vulnerability can be exploited remotely through network-based attacks against NTPsec implementations, making it particularly dangerous in networked environments where time synchronization services are critical.
Attackers can leverage this vulnerability to execute arbitrary code on affected systems or cause denial of service conditions by triggering the buffer over-read during normal operation. The over-read condition may expose sensitive information from adjacent memory locations, potentially including authentication credentials, cryptographic keys, or other confidential data stored in the process memory space. This vulnerability operates within the ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter, specifically targeting the ntpd service as a vector for privilege escalation or persistent access. The impact extends beyond simple service disruption to potentially compromise entire network infrastructure, given that NTP services are fundamental to network time synchronization and often run with elevated privileges. Organizations relying on NTPsec for time synchronization across their networks face significant risk exposure, particularly in environments where network time protocols are integral to security monitoring, logging, and authentication systems.
The recommended mitigation strategy involves immediate deployment of NTPsec version 1.1.3 or later, which includes proper bounds checking and input validation for control message processing. System administrators should also implement network segmentation and access controls to limit exposure of NTP services to untrusted networks, while monitoring for suspicious network traffic patterns that may indicate exploitation attempts. Additionally, regular security audits and vulnerability assessments should be conducted to identify and remediate similar issues in network infrastructure components, ensuring that all time synchronization services maintain up-to-date security patches and follow secure coding practices that prevent buffer over-read conditions.