CVE-2015-2754 in FreeXL
Summary
by MITRE
FreeXL before 1.0.0i allows remote attackers to cause a denial of service (stack corruption) and possibly execute arbitrary code via a crafted workbook, related to a "premature EOF."
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2015-2754 affects FreeXL versions prior to 1.0.0i, representing a critical security flaw that enables remote attackers to exploit stack corruption conditions within the library. This issue manifests when processing specially crafted Excel workbooks that contain premature end-of-file markers, creating a scenario where the application fails to properly validate input data structures before attempting to parse them. The vulnerability resides in how FreeXL handles malformed spreadsheet files, particularly those that terminate unexpectedly during parsing operations.
The technical exploitation of this vulnerability stems from improper input validation mechanisms within the FreeXL library's file parsing routines. When encountering a workbook with premature EOF conditions, the parser attempts to access memory locations beyond the allocated buffer boundaries, leading to stack corruption that can result in arbitrary code execution or complete denial of service. This type of vulnerability falls under the CWE-129 category of Improper Input Validation, specifically manifesting as an out-of-bounds read condition that can be leveraged for privilege escalation or system compromise. The flaw represents a classic buffer overflow scenario where the application does not properly verify the integrity of input data before processing, creating exploitable conditions that align with ATT&CK technique T1203 - Exploitation for Client Execution.
The operational impact of this vulnerability extends across various systems that utilize FreeXL for spreadsheet processing, including web applications, database connectors, and office automation tools that rely on this library for Excel file parsing. Attackers can craft malicious Excel files that, when processed by vulnerable applications, will trigger the stack corruption and potentially allow remote code execution with the privileges of the affected application. This makes the vulnerability particularly dangerous in environments where automated processing of user-uploaded files occurs, as it can be exploited through simple file uploads without requiring complex attack vectors or user interaction beyond the initial file processing.
Mitigation strategies for CVE-2015-2754 primarily involve upgrading to FreeXL version 1.0.0i or later, which includes proper input validation and boundary checking mechanisms to prevent premature EOF conditions from causing stack corruption. Organizations should also implement additional defensive measures such as input sanitization, file format validation, and sandboxed processing environments for Excel file handling. Network segmentation and access controls can help limit the potential impact of exploitation, while regular security assessments and vulnerability scanning should be conducted to identify systems running vulnerable versions. The remediation process should include thorough testing of updated libraries to ensure compatibility with existing applications while maintaining security posture against similar input validation flaws that may exist in other components of the system architecture.