CVE-2015-5213 in LibreOffice
Summary
by MITRE
Integer overflow in LibreOffice before 4.4.5 and Apache OpenOffice before 4.1.2 allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via a long DOC file, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 06/26/2022
The vulnerability identified as CVE-2015-5213 represents a critical integer overflow flaw affecting LibreOffice versions prior to 4.4.5 and Apache OpenOffice versions prior to 4.1.2. This security weakness resides in the document processing libraries of these office suites, specifically within their handling of Microsoft Word .doc file formats. The flaw manifests when the applications attempt to parse maliciously crafted DOC files containing excessively long data structures that trigger integer overflow conditions during memory allocation calculations. Such vulnerabilities fall under the CWE-190 category of Integer Overflow or Wraparound, which is a well-documented weakness in software security that occurs when an integer value exceeds its maximum representable value and wraps around to a smaller value, often causing unexpected behavior in memory management operations.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a specially malformed DOC file that contains oversized metadata or document elements designed to trigger the integer overflow during the parsing process. When the vulnerable office suite attempts to process this malicious document, the overflow condition causes the application to miscalculate buffer sizes, leading to memory corruption that manifests as application crashes or potentially allows for arbitrary code execution. The attack vector is particularly dangerous because it requires no user interaction beyond opening the malicious document, making it a classic example of a remote code execution vulnerability that can be delivered through email attachments or web downloads. The vulnerability is categorized under the ATT&CK technique T1203 - Exploitation for Client Execution, which describes how attackers leverage application vulnerabilities to execute malicious code on target systems.
The operational impact of CVE-2015-5213 extends beyond simple denial of service conditions to potentially enable full system compromise when exploited successfully. Organizations using affected versions of LibreOffice or Apache OpenOffice face significant risk as attackers can leverage this vulnerability to gain unauthorized access to systems, execute malicious payloads, or establish persistent backdoors. The memory corruption resulting from the buffer overflow can be particularly challenging to detect and remediate, as it may not always immediately crash the application but could leave systems in a vulnerable state. Security professionals must understand that this vulnerability represents a critical risk to enterprise environments where these office suites are commonly deployed, particularly in scenarios where users receive untrusted email attachments or browse untrusted websites. The vulnerability's potential for remote code execution makes it particularly attractive to threat actors conducting targeted attacks against organizations that have not yet applied the necessary security patches.
Mitigation strategies for CVE-2015-5213 focus primarily on immediate patch deployment and application of security updates provided by the respective software vendors. Organizations should prioritize updating to LibreOffice 4.4.5 or later and Apache OpenOffice 4.1.2 or later versions that contain the necessary fixes for the integer overflow conditions. Additionally, implementing network-based security controls such as email filtering and web content filtering can help prevent users from accessing malicious DOC files. Security teams should also consider implementing application whitelisting policies that restrict the execution of vulnerable office suite versions, while monitoring for suspicious document processing activities that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing comprehensive patch management processes to protect against known security flaws that could lead to system compromise.