CVE-2016-10327 in LibreOffice
Summary
by MITRE
LibreOffice before 2016-12-22 has an out-of-bounds write caused by a heap-based buffer overflow related to the EnhWMFReader::ReadEnhWMF function in vcl/source/filter/wmf/enhwmf.cxx.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/29/2022
The vulnerability identified as CVE-2016-10327 represents a critical heap-based buffer overflow within LibreOffice's document processing capabilities. This issue specifically affects versions prior to the December 22, 2016 release, indicating a window of exposure where users were susceptible to potential exploitation through maliciously crafted document files. The flaw manifests within the EnhWMFReader::ReadEnhWMF function located in the vcl/source/filter/wmf/enhwmf.cxx source file, which handles the parsing of Windows Metafile (WMF) format documents. The out-of-bounds write condition occurs when the application processes malformed WMF files that contain excessive or malformed data structures, leading to memory corruption that can be leveraged by attackers to execute arbitrary code on affected systems.
From a technical perspective, this vulnerability stems from inadequate input validation and bounds checking within the WMF parsing logic. The EnhWMFReader component is responsible for interpreting Windows Metafile graphics format, which is commonly used in office documents and various Microsoft Office applications. When processing specially crafted WMF data, the function fails to properly validate array indices or buffer sizes, allowing an attacker to write data beyond the allocated memory boundaries. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and represents a classic example of insufficient boundary checking in memory management operations. The vulnerability can be triggered through normal document opening operations, making it particularly dangerous as it requires no special privileges or user interaction beyond opening a malicious file.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain complete control over affected systems. Attackers exploiting this flaw could potentially execute malicious code with the privileges of the user running LibreOffice, leading to unauthorized system access, data theft, or further network compromise. The vulnerability's exploitation path aligns with ATT&CK technique T1203, "Exploitation for Client Execution," where adversaries leverage software vulnerabilities to execute code on target systems. Given that LibreOffice is widely used across various platforms and organizations, the potential attack surface is extensive, particularly in enterprise environments where document processing is a common activity. The vulnerability also represents a significant risk in phishing campaigns or targeted attacks where attackers could distribute malicious documents designed to exploit this specific flaw.
Mitigation strategies for CVE-2016-10327 primarily involve immediate patching of affected LibreOffice installations to version 5.2.5 or later, which includes the necessary fixes for the buffer overflow condition. Organizations should implement comprehensive patch management procedures to ensure all systems running LibreOffice are updated promptly. Additional protective measures include restricting document file types that can be opened through sandboxing mechanisms, implementing strict file validation policies, and monitoring for suspicious document processing activities. Security teams should also consider deploying network-based intrusion detection systems that can identify attempts to exploit this vulnerability through malformed document files. The vulnerability demonstrates the critical importance of proper input validation in document processing libraries and underscores the need for regular security assessments of office productivity software, particularly in enterprise environments where these applications are extensively used. Organizations should also consider implementing application whitelisting policies that restrict the execution of untrusted document processing applications to minimize potential impact from similar vulnerabilities.