CVE-2014-9296 in Communications Policy Management
Summary
by MITRE
The receive function in ntp_proto.c in ntpd in NTP before 4.2.8 continues to execute after detecting a certain authentication error, which might allow remote attackers to trigger an unintended association change via crafted packets.
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Analysis
by VulDB Data Team • 05/13/2019
The vulnerability identified as CVE-2014-9296 represents a critical flaw in the Network Time Protocol daemon implementation that affects versions prior to 428. This issue manifests within the ntp_proto.c file where the receive function fails to properly terminate execution upon detecting specific authentication errors. The flaw creates a condition where the protocol processing continues despite encountering malformed or maliciously crafted packets that should trigger immediate termination of the association process. This behavior fundamentally violates the expected error handling mechanisms that should prevent further processing of potentially harmful network traffic.
The technical implementation of this vulnerability stems from inadequate state management within the NTP daemon's protocol handling code. When authentication errors are detected during packet processing, the system should immediately abandon the current association and transition to a safe state. However, the flawed implementation allows execution to continue, potentially leading to unpredictable behavior in the association state machine. This continuation of execution creates opportunities for remote attackers to manipulate the protocol state through carefully constructed packets that exploit the incomplete error handling mechanism. The vulnerability specifically targets the authentication validation process where the system should reject malformed packets and terminate the association, but instead continues processing.
From an operational perspective, this vulnerability presents a significant risk to network time synchronization services that rely on NTP for accurate timekeeping. Remote attackers can exploit this flaw to manipulate the association state between NTP clients and servers, potentially causing time synchronization disruptions or creating conditions where malicious packets can influence the time protocol behavior. The impact extends beyond simple service disruption as it could enable more sophisticated attacks such as time poisoning or man-in-the-middle scenarios where attackers manipulate the time synchronization process. The vulnerability is particularly concerning in environments where precise time synchronization is critical for security operations, network logging, or cryptographic functions that depend on accurate timestamps.
The flaw aligns with CWE-457, which addresses the use of uninitialized variables or improper state handling in security-critical systems. This vulnerability also maps to ATT&CK technique T1071.004 related to application layer protocol manipulation, where attackers exploit protocol implementation weaknesses to achieve unauthorized behavior. Additionally, it corresponds to T1498 which covers network denial of service attacks, as the vulnerability could be exploited to disrupt time synchronization services. The recommended mitigation strategy involves upgrading to NTP version 4.2.8 or later where the authentication error handling has been corrected to properly terminate association processing upon detection of authentication failures. Organizations should also implement network segmentation and monitoring to detect unusual NTP traffic patterns that might indicate exploitation attempts. Network administrators should consider implementing rate limiting and packet filtering rules to reduce the attack surface while awaiting the software upgrade. The vulnerability demonstrates the importance of proper error handling in security-critical protocols and highlights the necessity of comprehensive testing for protocol state transitions under error conditions.