CVE-2022-46378 in uC-FTPs
Summary
by MITRE • 05/10/2023
An out-of-bounds read vulnerability exists in the PORT command parameter extraction functionality of Weston Embedded uC-FTPs v 1.98.00. A specially-crafted set of network packets can lead to denial of service. An attacker can send packets to trigger this vulnerability.This vulnerability occurs when no port argument is provided to the `PORT` command.
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Analysis
by VulDB Data Team • 06/02/2023
The vulnerability identified as CVE-2022-46378 represents a critical out-of-bounds read condition within the Weston Embedded uC-FTPs version 1.98.00 FTP server implementation. This flaw specifically manifests in the PORT command parameter extraction functionality, where the software fails to properly validate input parameters before processing them. The vulnerability stems from inadequate bounds checking mechanisms that allow the application to attempt reading memory locations beyond the allocated buffer boundaries when parsing FTP PORT command arguments. This particular implementation flaw demonstrates a classic software security weakness that can be exploited through improper input handling and memory management practices.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious network packets containing a PORT command with missing or malformed port arguments. When the uC-FTPs server processes such packets, the absence of proper parameter validation causes the application to access memory addresses that are outside the intended bounds of the allocated data structures. This out-of-bounds memory access typically results in application instability and can lead to complete system termination or denial of service conditions. The vulnerability specifically targets the command parsing logic where the server expects a specific format for the PORT command parameters but fails to account for cases where no port argument is provided, creating a scenario where the application attempts to read beyond valid memory regions.
From an operational perspective, this vulnerability poses significant risks to systems relying on Weston Embedded uC-FTPs for file transfer operations. The denial of service impact can disrupt legitimate FTP services and potentially affect critical infrastructure operations that depend on uninterrupted file transfer capabilities. Attackers can leverage this vulnerability to repeatedly send malformed PORT command packets, causing the FTP service to crash and requiring manual intervention for system recovery. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous in environments where FTP services are exposed to untrusted networks. This weakness directly impacts the availability aspect of the CIA triad and can be classified under CWE-129 as an improper input validation issue.
The security implications extend beyond simple service disruption to encompass potential system stability concerns and resource exhaustion attacks. When the out-of-bounds read occurs, the application may crash or enter an undefined state, leading to service unavailability for legitimate users. The vulnerability can be exploited as part of broader attack campaigns targeting FTP services, potentially serving as an initial access vector for more sophisticated attacks. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving service disruption and denial of service attacks, potentially enabling adversaries to establish persistent access through service manipulation. Organizations should implement immediate mitigations including firmware updates to the latest available version of uC-FTPs, network segmentation to limit exposure, and monitoring for suspicious FTP traffic patterns that may indicate exploitation attempts.
Mitigation strategies should focus on both immediate defensive measures and long-term architectural improvements. The primary recommendation involves updating the uC-FTPs software to a patched version that includes proper bounds checking and input validation for the PORT command functionality. Network administrators should implement access controls and firewall rules to restrict FTP service exposure, particularly to untrusted networks. Additional protective measures include deploying intrusion detection systems that can identify and alert on suspicious FTP protocol patterns, implementing rate limiting to prevent abuse of the vulnerable functionality, and establishing robust monitoring procedures to detect service disruptions. The vulnerability underscores the importance of proper input validation and memory safety practices in embedded systems, highlighting that even seemingly simple protocol implementations can contain critical security flaws that require careful attention to prevent exploitation.