CVE-2017-2919 in libxls
Summary
by MITRE
An exploitable stack based buffer overflow vulnerability exists in the xls_getfcell function of libxls 1.3.4. A specially crafted XLS file can cause a memory corruption resulting in remote code execution. An attacker can send malicious XLS file to trigger this vulnerability
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/11/2023
The vulnerability identified as CVE-2017-2919 represents a critical stack-based buffer overflow within the libxls library version 1.3.4, specifically within the xls_getfcell function. This flaw demonstrates a classic memory safety issue where insufficient bounds checking allows an attacker to write beyond allocated memory boundaries, potentially leading to arbitrary code execution. The vulnerability affects applications that utilize libxls for parsing Microsoft Excel files, making it particularly dangerous in environments where users may encounter untrusted spreadsheet content.
The technical implementation of this vulnerability stems from improper input validation within the xls_getfcell function which processes cell data from XLS files. When parsing malformed spreadsheet structures, the function fails to adequately verify array bounds before copying data to stack-allocated buffers. This allows an attacker to craft a malicious XLS file containing specially constructed cell data that exceeds the intended buffer capacity. The overflow occurs during the processing of spreadsheet cell coordinates and data structures, where the library does not properly validate the size of incoming data against allocated buffer space. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, representing a fundamental flaw in memory management practices.
The operational impact of this vulnerability extends far beyond simple data corruption, as it enables remote code execution capabilities for attackers. When an application utilizing libxls processes the malicious XLS file, the buffer overflow can overwrite adjacent stack memory, potentially corrupting return addresses and control flow information. This memory corruption can be leveraged to redirect program execution to attacker-controlled code, making it a highly attractive target for exploitation. The vulnerability affects a wide range of applications including office suites, document processing systems, and automated data analysis tools that depend on libxls for spreadsheet parsing functionality. Organizations using affected software may experience complete system compromise when users encounter malicious spreadsheets, particularly in environments where email attachments or web downloads are common attack vectors.
Mitigation strategies for CVE-2017-2919 should prioritize immediate patching of the libxls library to version 1.4.0 or later, which contains the necessary fixes for the buffer overflow condition. System administrators should implement strict file validation procedures for spreadsheet content, particularly when processing untrusted files from external sources. Network-based protections including email filtering and web application firewalls can help prevent delivery of malicious XLS files to end users. The ATT&CK framework categorizes this vulnerability under T1203 as "Exploitation for Client Execution," highlighting the need for layered defenses that include application whitelisting, sandboxing of spreadsheet processing, and regular security updates. Additionally, organizations should consider implementing automated vulnerability scanning tools that can detect the presence of vulnerable libxls versions and ensure proper remediation through patch management processes.