CVE-2022-46143 in SCALANCE
Summary
by MITRE • 12/13/2022
Affected devices do not check the TFTP blocksize correctly. This could allow an authenticated attacker to read from an uninitialized buffer that potentially contains previously allocated data.
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Analysis
by VulDB Data Team • 01/14/2025
This vulnerability resides in network devices that implement the Trivial File Transfer Protocol TFTP server functionality where the blocksize parameter validation is insufficient. The flaw occurs when the device fails to properly validate or sanitize the blocksize value provided by a client during a TFTP transfer operation. When an authenticated attacker sends a malformed or oversized blocksize request, the device processes this value without adequate bounds checking, leading to an uninitialized buffer read condition. The vulnerability specifically targets the TFTP server implementation within network infrastructure devices, where TFTP is commonly used for firmware updates, configuration file transfers, and other administrative operations. According to CWE-129, this represents an implementation weakness where insufficient input validation leads to buffer over-read conditions, while the ATT&CK framework categorizes this under privilege escalation and credential access techniques that leverage protocol implementation flaws. The uninitialized buffer read can potentially expose previously allocated memory contents, including sensitive data such as authentication tokens, configuration parameters, or other system information that may have been stored in the same memory regions. This vulnerability is particularly concerning because it requires only authentication to exploit, meaning that an attacker with valid credentials can potentially access previously allocated memory contents that may contain confidential information. The impact extends beyond simple information disclosure, as the leaked memory contents could contain cryptographic keys, passwords, or other sensitive data that could be leveraged for further attacks. Network administrators should consider this vulnerability as a potential entry point for privilege escalation attacks, especially in environments where TFTP is used for administrative functions. The security implications are significant because TFTP is often used for firmware updates and configuration management, making the device more susceptible to advanced persistent threats that could exploit this flaw to gain deeper access to the network infrastructure. Organizations should implement immediate mitigations including firmware updates from vendors, network segmentation to isolate TFTP services, and monitoring for unusual TFTP traffic patterns that might indicate exploitation attempts.
The vulnerability manifests when legitimate TFTP operations proceed through the device's TFTP server implementation, where the blocksize parameter controls the size of data packets transferred between client and server. When an attacker sends a request with an invalid blocksize value, the device's processing logic fails to validate the parameter against expected ranges, allowing the system to proceed with uninitialized memory operations. This creates a scenario where memory addresses that were previously used for other operations may still contain data from prior allocations, leading to the exposure of sensitive information. The flaw represents a classic buffer management issue where the device does not properly initialize memory buffers before use, creating a potential data leak channel that could be exploited by attackers with authenticated access. The security implications are amplified by the fact that TFTP is often used in network management contexts where devices may be configured with administrative credentials, making the attack surface larger than initially apparent. According to industry best practices and security frameworks, this type of vulnerability should be addressed through proper input validation, memory initialization procedures, and comprehensive testing of protocol implementations. The vulnerability also highlights the importance of secure coding practices and adherence to standards such as those defined in the CWE database, which categorizes this as a buffer overflow or read condition that can lead to information disclosure and potential privilege escalation. Organizations should treat this vulnerability as requiring immediate attention due to the potential for sensitive data exposure and the relatively low barrier to exploitation. The mitigation strategies should include not only patching the affected devices but also implementing network monitoring solutions that can detect anomalous TFTP behavior and establishing strict access controls for TFTP services to minimize the potential impact of such vulnerabilities.