CVE-2020-36617 in sftpserver
Summary
by MITRE • 12/18/2022
** DISPUTED ** A vulnerability was found in ewxrjk sftpserver. It has been declared as problematic. Affected by this vulnerability is the function sftp_parse_path of the file parse.c. The manipulation leads to uninitialized pointer. The real existence of this vulnerability is still doubted at the moment. The name of the patch is bf4032f34832ee11d79aa60a226cc018e7ec5eed. It is recommended to apply a patch to fix this issue. The identifier VDB-216205 was assigned to this vulnerability. NOTE: In some deployment models this would be a vulnerability. README specifically warns about avoiding such deployment models.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2020-36617 resides within the ewxrjk sftpserver software, specifically affecting the sftp_parse_path function located in the parse.c file. This issue represents a potential uninitialized pointer vulnerability that could lead to unpredictable behavior within the system. The nature of uninitialized pointers typically creates conditions where memory locations contain arbitrary data, potentially leading to security implications including information disclosure, privilege escalation, or denial of service scenarios. The vulnerability has been classified as disputed by the vendor, indicating uncertainty regarding its actual existence or severity within real-world deployments.
The technical flaw manifests when the sftp_parse_path function processes path-related data structures without proper initialization of pointer variables. This uninitialized pointer condition falls under CWE-457, which specifically addresses the use of uninitialized variables in software development. When pointers remain uninitialized, they may contain garbage values from previous memory operations, creating potential attack vectors where malicious actors could exploit these unpredictable pointer states to manipulate program flow or access unauthorized memory regions. The function's operation in parsing SFTP paths creates a critical juncture where improper initialization could compromise the entire secure file transfer process.
From an operational standpoint, the impact of this vulnerability depends heavily on the deployment model used for the sftpserver implementation. The vulnerability's classification as disputed suggests that its actual exploitation potential varies significantly across different environments and usage patterns. The assigned identifier VDB-216205 indicates this issue has been recognized by vulnerability databases, though the uncertainty surrounding its validity means organizations must carefully evaluate their specific configurations. The advisory notes that certain deployment models may be more susceptible to exploitation than others, making environment-specific risk assessment crucial for proper vulnerability management.
The recommended mitigation strategy involves applying the patch identified by the commit hash bf4032f34832ee11d79aa60a226cc018e7ec5eed, which addresses the uninitialized pointer issue in the affected function. Organizations should also carefully review their deployment models to ensure they avoid configurations that might expose the system to this vulnerability, as suggested by the README file's explicit warnings. This vulnerability demonstrates the importance of proper memory management practices in security-critical applications, particularly in protocols like SFTP where authentication and authorization mechanisms are paramount. The potential for this issue to create security weaknesses in file transfer operations underscores the necessity of thorough code review and testing processes, aligning with ATT&CK technique T1068 which focuses on exploit development and privilege escalation vectors. Given the disputed nature of this vulnerability, security teams should monitor for additional information and consider the specific risk profile of their environments before implementing any remediation measures.