CVE-2022-23935 in ExifTool
Summary
by MITRE • 01/25/2022
lib/Image/ExifTool.pm in ExifTool before 12.38 mishandles a $file =~ /\|$/ check.
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Analysis
by VulDB Data Team • 01/28/2022
The vulnerability identified as CVE-2022-23935 affects ExifTool version 12.37 and earlier, specifically within the lib/Image/ExifTool.pm module where a flawed regular expression pattern fails to properly validate file input. This issue stems from the improper handling of the pattern $file =~ /\|$/ which is designed to detect pipe characters at the end of file paths but contains a logical flaw that could allow malicious input to bypass intended security checks. The vulnerability represents a classic example of insufficient input validation and improper error handling that can lead to unexpected behavior in file processing operations.
The technical flaw manifests when ExifTool processes image files that contain pipe characters in their filenames or paths, particularly when these characters appear at the end of file names. The regular expression /\|$/ is intended to identify such cases but due to its implementation, it fails to properly sanitize or reject potentially dangerous file paths that could be exploited to manipulate the tool's behavior. This misconfiguration allows attackers to craft file names that could cause ExifTool to process unintended files or execute commands through improper file path handling. The vulnerability falls under CWE-20, which addresses improper input validation, and represents a specific instance of CWE-78, which deals with OS command injection through improper input sanitization.
The operational impact of this vulnerability extends beyond simple file processing errors and could potentially enable attackers to perform unauthorized file operations or gain access to unintended system resources. When ExifTool processes maliciously crafted file names containing pipe characters, the improper regex handling could lead to unexpected execution paths that might allow for command injection or file access violations. This risk is particularly concerning in environments where ExifTool is used to process untrusted image files from external sources, as it could be exploited to execute arbitrary code on the system running the tool. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, specifically focusing on the execution of shell commands through improper input handling.
Mitigation strategies for CVE-2022-23935 should prioritize immediate patching to ExifTool version 12.38 or later, which contains the corrected implementation of the file path validation logic. Organizations should also implement additional input sanitization measures at the system level, including proper file name validation before ExifTool processing and monitoring for unusual file access patterns. Network administrators should consider implementing file type restrictions and sandboxing techniques when processing potentially malicious image files. The fix addresses the root cause by properly implementing the regular expression pattern to ensure that pipe characters at the end of file paths are appropriately handled and rejected when they represent potential attack vectors. Security teams should also conduct thorough vulnerability assessments of systems using ExifTool to identify any potential exploitation attempts that may have occurred prior to patching.