CVE-2018-10387 in TFTP Server SP
Summary
by MITRE
Heap-based overflow vulnerability in TFTP Server SP 1.66 and earlier allows remote attackers to perform a denial of service or possibly execute arbitrary code via a long TFTP error packet, a different vulnerability than CVE-2008-2161.
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Analysis
by VulDB Data Team • 03/16/2024
The heap-based buffer overflow vulnerability identified as CVE-2018-10387 affects TFTP Server version 1.66 and earlier implementations, representing a critical security flaw that enables remote attackers to compromise system integrity. This vulnerability specifically manifests when the server processes malformed TFTP error packets containing excessive data lengths, creating conditions where memory allocation operations exceed predetermined buffer boundaries. The flaw resides in the server's handling of error packet structures, where insufficient input validation allows attackers to craft malicious packets that trigger memory corruption during processing. Unlike CVE-2008-2161 which targeted different aspects of TFTP functionality, this vulnerability operates through a distinct code path involving heap memory management and error response generation. The vulnerability maps to CWE-121, heap-based buffer overflow, which is classified as a serious weakness in memory management and input validation practices. From an operational perspective, this vulnerability presents a significant risk as it can be exploited remotely without authentication requirements, making it particularly dangerous in networked environments where TFTP servers are commonly deployed for file transfer operations. Attackers can leverage this flaw to either induce denial of service conditions by crashing the TFTP server process or potentially achieve arbitrary code execution within the server's operational context. The heap corruption occurs when the server attempts to allocate memory for processing oversized error packets, leading to memory corruption that can be manipulated to redirect program execution flow. The attack surface is particularly concerning given that TFTP servers often run with elevated privileges and may be accessible from untrusted networks, providing attackers with potential pathways for further system compromise.
The operational impact of CVE-2018-10387 extends beyond simple service disruption to encompass potential system compromise and data integrity violations. When exploited successfully, the vulnerability allows attackers to execute arbitrary code with the privileges of the TFTP server process, potentially enabling lateral movement within network segments where the server operates. The heap-based nature of the vulnerability means that memory corruption can affect critical server components including heap metadata structures, leading to unpredictable behavior and potential exploitation through techniques such as return-oriented programming or stack pivoting. Security analysts should note that this vulnerability aligns with ATT&CK technique T1072, "Software Deployment Tools," as TFTP servers are often used for legitimate software distribution but can be weaponized for malicious purposes. The vulnerability's remote exploitability without authentication requirements makes it particularly attractive to threat actors seeking to establish persistent access points within target networks. Network defenders must consider that TFTP servers frequently operate in environments where they are not properly monitored or patched, creating ideal conditions for exploitation. The vulnerability's potential for code execution means that attackers could install backdoors, modify system files, or exfiltrate sensitive data through the compromised TFTP server. Organizations should also recognize that the vulnerability affects a broad range of systems where TFTP functionality is implemented, including network infrastructure devices, embedded systems, and legacy applications that may not receive regular security updates.
Mitigation strategies for CVE-2018-10387 should prioritize immediate patching of affected TFTP server implementations to address the heap-based buffer overflow conditions. Organizations must implement network segmentation to limit access to TFTP servers and restrict their exposure to untrusted networks, as outlined in the NIST SP 800-53 security controls. The implementation of network access controls including firewall rules and access control lists can help prevent unauthorized access to TFTP services. Additionally, organizations should deploy intrusion detection systems capable of identifying suspicious TFTP error packet patterns that may indicate exploitation attempts. Regular security assessments and vulnerability scanning should include checks for TFTP server installations and their versions to ensure proper patch management. System administrators should consider disabling TFTP services when not required for business operations, as recommended by the Center for Internet Security benchmarks. The vulnerability requires careful monitoring of heap memory operations and implementation of proper input validation mechanisms to prevent buffer overflows. Organizations should also establish incident response procedures that include specific handling of TFTP-related security incidents and potential exploitation indicators. Logging and monitoring solutions should be configured to detect unusual TFTP error packet sizes or patterns that could indicate exploitation attempts. The security community should also consider the broader implications of heap-based vulnerabilities in network services and implement comprehensive memory safety practices including address space layout randomization and stack canaries to mitigate potential exploitation vectors.