CVE-2017-16892 in bftpd
Summary
by MITRE
In Bftpd before 4.7, there is a memory leak in the file rename function.
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Analysis
by VulDB Data Team • 12/09/2019
The vulnerability identified as CVE-2017-16892 represents a memory leak condition within the Bftpd file transfer protocol server implementation prior to version 4.7. This memory leak specifically occurs within the file rename functionality of the service, creating a persistent resource consumption issue that can degrade system performance over time. The flaw exists in the way the application handles memory allocation and deallocation during the file renaming process, where allocated memory blocks are not properly released back to the system after successful operations. This type of vulnerability falls under the category of memory management errors that can lead to gradual resource exhaustion and potential service disruption.
The technical implementation of this vulnerability stems from improper memory handling within the rename function, where the application allocates memory for processing file rename operations but fails to execute proper deallocation routines. This memory leak can be exploited through repeated calls to the rename functionality, causing the server process to consume increasing amounts of memory until system resources become exhausted. The flaw represents a classic example of a CWE-401: Improper Release of Memory Before Removing Last Reference, which is categorized under the broader family of memory management vulnerabilities that affect software systems. The vulnerability demonstrates a fundamental failure in resource management practices within the application's core functionality.
The operational impact of this memory leak vulnerability extends beyond simple performance degradation, as it can potentially lead to complete service unavailability for legitimate users. Attackers can exploit this weakness by continuously invoking the rename function, causing the Bftpd server to gradually consume all available memory resources. This can result in system instability, application crashes, and denial of service conditions that affect authorized users attempting to perform legitimate file operations. The vulnerability is particularly concerning in environments where the Bftpd service operates continuously and handles multiple concurrent connections, as the memory consumption can escalate rapidly and become difficult to predict or manage without proper monitoring.
Mitigation strategies for CVE-2017-16892 primarily focus on updating to Bftpd version 4.7 or later, where the memory leak has been addressed through proper memory management practices. System administrators should implement regular monitoring of memory usage patterns for the Bftpd service to detect unusual consumption trends that may indicate exploitation attempts. Additionally, implementing resource limits and process monitoring can help contain the impact of memory leaks before they cause complete service disruption. The vulnerability aligns with ATT&CK technique T1499.001: Network Denial of Service, as it can be leveraged to create resource exhaustion conditions that prevent legitimate access to the file transfer service. Organizations should also consider implementing automated patch management processes to ensure timely deployment of security updates and prevent exploitation of known vulnerabilities in their file transfer infrastructure.