CVE-2018-7182 in ntp
Summary
by MITRE
The ctl_getitem method in ntpd in ntp-4.2.8p6 before 4.2.8p11 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted mode 6 packet with a ntpd instance from 4.2.8p6 through 4.2.8p10.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2018-7182 represents a critical out-of-bounds read flaw within the Network Time Protocol daemon implementation in ntp-4.2.8p6 through 4.2.8p10 versions. This issue specifically affects the ctl_getitem method which processes control mode packets, particularly those transmitted using mode 6 communication. The vulnerability manifests when a remote attacker crafts a specially formatted packet that exploits memory access patterns within the ntpd process, leading to unauthorized memory reads beyond the intended buffer boundaries. Such out-of-bounds memory access represents a fundamental violation of memory safety principles and creates opportunities for information disclosure or system instability.
The technical exploitation of this vulnerability occurs through the manipulation of control mode 6 packets that ntpd accepts for communication with remote systems. When ntpd processes these packets, the ctl_getitem method fails to properly validate the length or structure of incoming data, allowing attackers to specify memory offsets that extend beyond allocated buffer boundaries. This flaw enables attackers to read arbitrary memory locations, potentially exposing sensitive information such as cryptographic keys, system memory contents, or internal process data. The vulnerability operates at the protocol level within the ntp daemon's control interface, making it particularly dangerous as it can be exploited without requiring authentication or privileged access. The out-of-bounds read condition creates a potential information disclosure vector that could be leveraged in combination with other techniques to achieve more severe impacts.
The operational impact of CVE-2018-7182 extends beyond simple denial of service to encompass potential information leakage and system compromise. While the immediate effect is a denial of service through process termination or memory corruption, the out-of-bounds read capability creates opportunities for attackers to extract sensitive data from system memory. This vulnerability affects systems running ntpd versions in the specified range, which includes numerous enterprise and infrastructure deployments where time synchronization services are critical. The remote exploitation capability means that attackers can target vulnerable systems from anywhere on the network, making this vulnerability particularly dangerous for organizations with exposed ntpd instances. The impact is amplified when considering that ntpd typically runs with elevated privileges, potentially allowing attackers to gain access to sensitive system information.
Mitigation strategies for CVE-2018-7182 focus primarily on upgrading to patched versions of ntpd, specifically versions 4.2.8p11 and later, which contain the necessary code modifications to prevent out-of-bounds memory access. Organizations should prioritize patching their ntpd installations, particularly those exposed to untrusted networks or internet-facing systems. Network segmentation and firewall rules can provide temporary protection by restricting access to ntpd services, though this approach does not address the underlying vulnerability. Additional defensive measures include implementing network monitoring to detect anomalous mode 6 packet traffic patterns and enabling intrusion detection systems that can identify potential exploitation attempts. The vulnerability aligns with CWE-125 Out-of-bounds Read, which classifies memory access violations that allow reading beyond allocated buffer boundaries. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1071.004 Application Layer Protocol Network Traffic Filtering, as it involves manipulation of network protocol communications to achieve system compromise, and T1005 Data from Local System, as it enables information disclosure from system memory.