CVE-2015-2753 in FreeXL
Summary
by MITRE
FreeXL before 1.0.0i allows remote attackers to cause a denial of service (stack corruption) or possibly execute arbitrary code via a crafted sector in a workbook.
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2015-2753 affects FreeXL versions prior to 1.0.0i, representing a critical security flaw in the library responsible for parsing Excel file formats. This issue manifests through a stack corruption vulnerability that can be triggered by maliciously crafted sector data within workbook files, potentially leading to remote code execution or denial of service conditions. The vulnerability stems from inadequate input validation and memory management practices within the FreeXL parsing engine, which processes Microsoft Excel files without proper bounds checking mechanisms.
Technical exploitation of this vulnerability occurs when an attacker crafts a malicious Excel workbook containing specially designed sector data that, when processed by the vulnerable FreeXL library, causes stack corruption through buffer overflows or improper memory access patterns. The flaw operates at the parsing layer where the library attempts to read and interpret structured data within Excel files, particularly focusing on how it handles sector allocation and data structure interpretation. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and can be categorized as a memory safety issue within the software's data processing pipeline. The attack vector is remote, meaning an attacker can deliver the malicious file through network-based delivery mechanisms such as email attachments, web downloads, or file sharing platforms.
The operational impact of CVE-2015-2753 extends beyond simple denial of service scenarios to potentially enable remote code execution on systems that utilize the vulnerable FreeXL library. This risk materializes when applications relying on FreeXL for Excel file processing are exposed to untrusted input from external sources, creating opportunities for attackers to gain unauthorized system access. The vulnerability affects various software applications that integrate FreeXL for spreadsheet processing capabilities, including but not limited to business intelligence tools, data analysis platforms, and document management systems. Systems utilizing vulnerable versions face significant risk when processing Excel files from unknown or untrusted sources, as the parsing operation becomes a potential attack surface for privilege escalation or persistent system compromise.
Mitigation strategies for this vulnerability require immediate patching of affected FreeXL installations to version 1.0.0i or later, which incorporates proper input validation and memory management fixes. Organizations should implement comprehensive network segmentation and access controls to limit exposure of systems that process Excel files, particularly those handling external data inputs. Additional defensive measures include deploying web application firewalls, implementing strict file type validation, and establishing secure coding practices for applications that utilize FreeXL libraries. The vulnerability demonstrates the importance of input sanitization and memory safety practices in file processing libraries, aligning with ATT&CK technique T1059 for command and script injection, and T1489 for denial of service through resource consumption. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other third-party libraries and ensure that proper security controls are in place to prevent exploitation of similar memory corruption issues.