CVE-2015-7848 in ntpd
Summary
by MITRE
An integer overflow can occur in NTP-dev.4.3.70 leading to an out-of-bounds memory copy operation when processing a specially crafted private mode packet. The crafted packet needs to have the correct message authentication code and a valid timestamp. When processed by the NTP daemon, it leads to an immediate crash.
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Analysis
by VulDB Data Team • 04/20/2025
The vulnerability identified as CVE-2015-7848 represents a critical integer overflow flaw within the Network Time Protocol daemon version 4.3.70. This issue manifests specifically during the processing of private mode packets, which are part of the NTP protocol's authentication framework designed to ensure message integrity and authenticity. The vulnerability resides in the daemon's handling of packet validation and memory allocation procedures, where improper bounds checking allows for arithmetic overflow conditions that can be exploited by malicious actors.
The technical implementation of this vulnerability involves an integer overflow occurring in the NTP daemon's packet processing logic when it encounters specially crafted private mode packets. These packets must contain a valid message authentication code and proper timestamp values to successfully trigger the vulnerability. The flaw arises from the daemon's failure to properly validate the size parameters of incoming packets before attempting memory allocation operations. When the overflow occurs, it results in an out-of-bounds memory copy operation that fundamentally corrupts the process memory space and leads to immediate daemon termination.
From an operational perspective, this vulnerability presents a significant denial of service risk to network time synchronization services that rely on NTP implementations. The attack vector requires only a single malicious packet to be sent to a vulnerable NTP daemon, making it particularly dangerous in environments where network time synchronization is critical for security operations. The immediate crash effect means that legitimate time synchronization services become unavailable, potentially disrupting cascading security systems that depend on synchronized time stamps for log correlation, authentication mechanisms, and cryptographic operations.
The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, which specifically addresses issues where integer arithmetic operations produce results that exceed the maximum value representable by the data type. This flaw also maps to ATT&CK technique T1499.001, Network Denial of Service, as it enables adversaries to disrupt network services through carefully crafted network traffic. The impact extends beyond simple service disruption to potentially affecting security infrastructure that depends on accurate time synchronization for proper operation, including intrusion detection systems, security information and event management systems, and various authentication protocols that rely on time-based tokens.
Mitigation strategies for CVE-2015-7848 should prioritize immediate patching of affected NTP daemon versions to the latest stable releases that contain proper integer overflow protections. Network administrators should implement rate limiting and packet filtering mechanisms to reduce the effectiveness of potential attacks while patches are deployed. Additionally, monitoring systems should be configured to detect unusual daemon crash patterns that might indicate exploitation attempts. The fix typically involves implementing proper input validation and bounds checking before memory allocation operations, ensuring that packet size parameters are properly validated against maximum allowable values before any memory operations are performed.