CVE-2018-7441 in Leptonica
Summary
by MITRE
Leptonica through 1.75.3 uses hardcoded /tmp pathnames, which might allow local users to overwrite arbitrary files or have unspecified other impact by creating files in advance or winning a race condition, as demonstrated by /tmp/junk_split_image.ps in prog/splitimage2pdf.c.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7441 affects Leptonica versions through 1.75.3 and represents a critical security flaw related to improper temporary file handling. This issue stems from the library's use of hardcoded /tmp pathnames in its file operations, creating exploitable conditions that can be leveraged by local attackers to manipulate system resources. The vulnerability specifically manifests in the prog/splitimage2pdf.c component where the application creates temporary files using the hardcoded /tmp/junk_split_image.ps path, establishing a predictable attack surface that can be exploited through various malicious techniques.
The technical implementation of this vulnerability involves a race condition scenario where an attacker can anticipate and manipulate the creation of temporary files in the /tmp directory. When Leptonica processes image files through the splitimage2pdf functionality, it generates temporary files at predetermined locations within the system's temporary directory. This hardcoded approach creates a deterministic attack vector where malicious users can pre-create symbolic links or files at the expected locations, causing the vulnerable application to write data to unintended targets. The flaw essentially allows attackers to bypass normal file access controls and potentially overwrite arbitrary files on the system, as the application does not implement proper validation or secure temporary file creation mechanisms.
From an operational perspective, this vulnerability presents significant risks to systems running affected versions of Leptonica, particularly in multi-user environments or when the library is used in security-sensitive applications. The impact extends beyond simple file overwrites to potentially enable privilege escalation scenarios, especially when the vulnerable application runs with elevated privileges. Attackers can exploit this weakness to inject malicious content into system files, disrupt services, or establish persistent access points within the target environment. The unspecified nature of some impacts suggests that the vulnerability could potentially enable more sophisticated attacks depending on the system configuration and the privileges under which the vulnerable application executes.
The vulnerability aligns with CWE-377: Insecure Temporary File and CWE-378: Creation of Temporary File With Insecure Permissions, both of which address the fundamental security issues of improper temporary file handling in software applications. From an attack framework perspective, this vulnerability maps to multiple ATT&CK techniques including T1059.001 for command and scripting interpreter execution and potentially T1068 for local privilege escalation. Organizations should implement immediate mitigations including upgrading to patched versions of Leptonica, implementing proper temporary file handling mechanisms, and conducting thorough security audits of systems that utilize this library. Additionally, system administrators should monitor for suspicious file creation patterns in /tmp directories and consider implementing file system permissions that restrict write access to temporary directories for non-privileged users. The remediation process should include not only updating the vulnerable library but also reviewing all applications that may be indirectly affected by this temporary file handling weakness, as similar patterns might exist in other components of the system infrastructure.