CVE-2024-27619 in DIR-3040us A1
Summary
by MITRE • 03/29/2024
Dlink Dir-3040us A1 1.20b03a hotfix is vulnerable to Buffer Overflow. Any user having read/write access to ftp server can write directly to ram causing buffer overflow if file or files uploaded are greater than available ram. Ftp server allows change of directory to root which is one level up than root of usb flash directory. During upload ram is getting filled and causing system resource exhaustion (no free memory) which causes system to crash and reboot.
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Analysis
by VulDB Data Team • 09/04/2024
The CVE-2024-27619 vulnerability affects the D-Link DIR-3040US A1 1.20b03a router model and represents a critical buffer overflow condition within the device's FTP server implementation. This vulnerability stems from inadequate input validation and memory management practices within the embedded system's file transfer protocols. The flaw specifically manifests when users with read/write privileges to the FTP server attempt to upload files that exceed the available RAM capacity, creating a scenario where the system's memory allocation mechanisms fail catastrophically. The vulnerability operates through a combination of improper boundary checking and insufficient memory allocation controls that allow malicious file uploads to overflow buffer structures and corrupt system memory.
The technical exploitation of this vulnerability occurs through the FTP server's directory traversal capabilities, which permit users to navigate to the root level of the USB flash storage directory. This privilege escalation path, combined with the memory exhaustion vulnerability, creates a particularly dangerous attack vector where an attacker can strategically upload files to fill system RAM completely. The system's inability to properly handle memory allocation during these large file transfers results in a complete system resource exhaustion condition that ultimately leads to device crash and automatic reboot. This behavior demonstrates a fundamental flaw in the router's memory management subsystem that lacks proper safeguards against memory overflow conditions.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable more sophisticated attack scenarios. The automatic reboot functionality can be leveraged by attackers to disrupt network services, creating denial-of-service conditions that compromise network availability. From a cybersecurity perspective, this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. The vulnerability also maps to ATT&CK technique T1499.004, which involves network disruption through resource exhaustion attacks, and potentially T1059.007 for command execution through compromised network services. The device's failure to implement proper memory bounds checking and allocation limits creates an environment where legitimate file operations can trigger catastrophic system failures.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and memory management controls within the FTP server implementation. Network administrators should immediately disable FTP services if not required for operational purposes, as this reduces the attack surface significantly. The recommended approach includes implementing strict file size limitations for FTP uploads, establishing proper memory allocation bounds checking, and implementing robust error handling for memory exhaustion scenarios. Additionally, the device firmware should be updated to a version that properly addresses the buffer overflow conditions and includes enhanced memory management controls. Regular monitoring of system memory usage and implementation of automated alerting mechanisms for memory exhaustion conditions can help detect potential exploitation attempts before they cause complete system failure. Organizations should also consider network segmentation and access control measures to limit who can access the FTP server functionality, as the vulnerability requires existing read/write privileges to exploit effectively.