CVE-2023-45283 in Google
Summary
by MITRE • 11/09/2023
The filepath package does not recognize paths with a \??\ prefix as special. On Windows, a path beginning with \??\ is a Root Local Device path equivalent to a path beginning with \\?\. Paths with a \??\ prefix may be used to access arbitrary locations on the system. For example, the path \??\c:\x is equivalent to the more common path c:\x. Before fix, Clean could convert a rooted path such as \a\..\??\b into the root local device path \??\b. Clean will now convert this to .\??\b. Similarly, Join(\, ??, b) could convert a seemingly innocent sequence of path elements into the root local device path \??\b. Join will now convert this to \.\??\b. In addition, with fix, IsAbs now correctly reports paths beginning with \??\ as absolute, and VolumeName correctly reports the \??\ prefix as a volume name.
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Analysis
by VulDB Data Team • 12/06/2023
The vulnerability identified as CVE-2023-45283 resides within the filepath package of Go programming language, representing a critical security flaw that undermines the operating system's path resolution mechanisms. This issue specifically affects Windows systems where the kernel employs special path prefixes to handle device access and file system operations. The \??\ prefix is a Root Local Device path that Windows uses to reference system resources directly without going through the normal file system resolution process, effectively bypassing standard access controls and path validation.
The technical flaw stems from the filepath package's inability to properly identify and handle paths that begin with the \??\ prefix, which should be recognized as equivalent to the \?\ prefix used for similar purposes. This oversight allows malicious actors to exploit the system by crafting paths that leverage this special prefix to access arbitrary locations on the file system. When the Go runtime processes these paths through the filepath package, it fails to normalize or validate them properly, potentially leading to directory traversal attacks or unauthorized file access. The vulnerability creates a direct pathway for attackers to circumvent normal file system security boundaries that should otherwise prevent access to protected system locations.
The operational impact of this vulnerability extends beyond simple path resolution issues and represents a significant threat to system integrity and data confidentiality. Attackers can exploit this flaw to gain unauthorized access to system files, configuration data, or user information stored in locations that should normally be protected. This vulnerability is particularly dangerous in environments where Go applications handle user-provided input or process external file paths, as it allows for privilege escalation and potential lateral movement within the network. The attack surface is broad since any Go application that processes file paths on Windows systems could be vulnerable, including web applications, system utilities, and enterprise software solutions.
Security professionals should implement immediate mitigations including updating to the patched version of Go that addresses this vulnerability, which is specifically designed to normalize and properly handle paths beginning with the \??\ prefix. Organizations should also consider implementing input validation measures that sanitize all file path inputs before they are processed by any Go application, particularly in web-facing services. The vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and can be categorized under ATT&CK technique T1059.007 (Command and Scripting Interpreter: Python) when exploited through path manipulation attacks. Additionally, system administrators should monitor for unusual file access patterns or attempts to access system directories that could indicate exploitation attempts. The fix implemented by the Go team specifically addresses the path normalization logic to ensure that \??\ prefixes are treated equivalently to \?\ prefixes, thereby maintaining proper security boundaries within the file system access controls.
This vulnerability demonstrates the critical importance of proper path handling in security-sensitive applications and highlights the need for comprehensive testing of file system interactions, particularly in cross-platform environments where different operating systems may implement similar but subtly different path resolution mechanisms. The issue serves as a reminder that even seemingly minor implementation details in core libraries can have significant security implications when dealing with operating system-specific path conventions and access controls.