CVE-2009-0159 in ntp
Summary
by MITRE
Stack-based buffer overflow in the cookedprint function in ntpq/ntpq.c in ntpq in NTP before 4.2.4p7-RC2 allows remote NTP servers to execute arbitrary code via a crafted response.
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Analysis
by VulDB Data Team • 07/10/2018
The vulnerability described in CVE-2009-0159 represents a critical stack-based buffer overflow affecting the Network Time Protocol implementation in ntpq utility. This flaw exists within the cookedprint function located in ntpq/ntpq.c file of NTP versions prior to 4.2.4p7-RC2, creating a significant security risk that can be exploited by remote attackers. The vulnerability manifests when the ntpq utility processes responses from NTP servers, specifically during the parsing of time synchronization data that includes crafted malicious payloads designed to overflow the stack buffer.
The technical implementation of this vulnerability stems from inadequate input validation within the cookedprint function which handles formatted output of NTP server responses. When ntpq receives a response containing specially crafted data, the function fails to properly bounds-check the input before copying it into a fixed-size stack buffer. This allows an attacker controlling a remote NTP server to inject malicious data exceeding the buffer capacity, resulting in stack corruption that can be leveraged to execute arbitrary code on the victim system. The flaw operates at the protocol level where legitimate time synchronization communications become vectors for code execution, making it particularly dangerous in networked environments where NTP servers are commonly used.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with the ability to compromise systems running vulnerable NTP implementations. Given that NTP is widely deployed across network infrastructure, including servers, workstations, and network devices, the potential attack surface is extensive. An attacker could exploit this vulnerability to gain unauthorized access to systems, potentially escalating privileges or establishing persistent access. The attack requires the attacker to control or compromise an NTP server that the target system communicates with, but since NTP is commonly used in both internal and external network communications, this presents a realistic threat vector. The vulnerability also aligns with ATT&CK technique T1059.007 for command and scripting interpreter and could be used for privilege escalation through code injection.
Mitigation strategies for CVE-2009-0159 focus primarily on upgrading to NTP versions 4.2.4p7-RC2 or later where the buffer overflow has been addressed through proper bounds checking and input validation. Network administrators should also implement additional security controls such as restricting NTP server access to trusted sources, implementing NTP authentication mechanisms, and monitoring for unusual NTP traffic patterns that might indicate exploitation attempts. The fix implemented in the patched versions involves proper validation of input data lengths before buffer operations, preventing the overflow condition that previously allowed arbitrary code execution. Organizations should also consider implementing network segmentation and firewall rules to limit NTP communication to authorized servers only, reducing the attack surface and potential impact of such vulnerabilities. This vulnerability demonstrates the importance of input validation in network protocols and aligns with CWE-121 which addresses stack-based buffer overflow conditions, emphasizing the need for robust bounds checking in all input processing functions.