CVE-2018-7442 in Leptonica
Summary
by MITRE
An issue was discovered in Leptonica through 1.75.3. The gplotMakeOutput function does not block '/' characters in the gplot rootname argument, potentially leading to path traversal and arbitrary file overwrite.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7442 resides within the Leptonica library version 1.75.3 and earlier, representing a critical path traversal flaw in the gplotMakeOutput function. This issue stems from inadequate input validation mechanisms that fail to properly sanitize the rootname argument, allowing maliciously crafted input containing forward slash characters to manipulate file system operations. The vulnerability specifically affects the graphics plotting functionality of the library, which is commonly used for generating various types of plots and visualizations in image processing applications.
The technical implementation of this flaw occurs when the gplotMakeOutput function processes user-provided rootname values without proper filtering of special characters, particularly the forward slash character that serves as a path separator in Unix-like systems and Windows environments. When an attacker provides a rootname argument containing path traversal sequences such as "../" or "/../", the function fails to validate these inputs, enabling unauthorized access to arbitrary file paths within the system. This weakness directly maps to CWE-22, which categorizes path traversal vulnerabilities as a common security flaw where applications fail to properly validate or sanitize user-supplied path information.
The operational impact of this vulnerability extends beyond simple file access manipulation, as it can potentially lead to arbitrary file overwrite scenarios that compromise system integrity and data confidentiality. Attackers could leverage this flaw to overwrite critical system files, configuration files, or sensitive data stored in unintended locations, particularly when the vulnerable library is used in applications with elevated privileges or in server environments where file system access is restricted. The vulnerability becomes particularly dangerous when the affected application processes untrusted input from external sources, such as user uploads or network requests, as it allows for remote exploitation without requiring authentication.
Security practitioners should implement multiple layers of mitigation strategies to address this vulnerability, beginning with immediate patching of affected Leptonica versions to 1.76.0 or later where the input validation has been properly enhanced. Additionally, applications utilizing the vulnerable library should implement input sanitization routines that explicitly filter or escape special characters, particularly forward slashes, from user-provided parameters before they reach the gplotMakeOutput function. The ATT&CK framework categorizes this type of vulnerability under T1059 Command and Scripting Interpreter and T1566 Phishing with Malicious Attachment, as attackers could exploit this weakness in conjunction with social engineering campaigns to deliver malicious payloads through compromised applications. Organizations should also consider implementing application whitelisting policies and restricting file system permissions for applications that utilize the affected library, ensuring that even if exploitation occurs, the impact remains contained within limited system access boundaries.