CVE-2020-13546 in Office TextMaker
Summary
by MITRE • 02/10/2021
In SoftMaker Software GmbH SoftMaker Office TextMaker 2021 (revision 1014), a specially crafted document can cause the document parser to miscalculate a length used to allocate a buffer, later upon usage of this buffer the application will write outside its bounds resulting in a heap-based buffer overflow. An attacker can entice the victim to open a document to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/27/2021
The vulnerability identified as CVE-2020-13546 represents a critical heap-based buffer overflow in SoftMaker Office TextMaker 2021 version 1014, demonstrating a classic memory safety issue that has significant implications for application stability and security. This flaw exists within the document parsing functionality where the application fails to properly validate or calculate buffer sizes during document processing, creating an exploitable condition that can be triggered by maliciously crafted input files.
The technical root cause of this vulnerability stems from improper bounds checking within the document parser component of TextMaker 2021. When processing specially crafted documents, the application calculates a buffer size that is insufficient for the actual data being processed, leading to a situation where subsequent memory operations attempt to write beyond the allocated buffer boundaries. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, though the heap-based nature of this particular issue requires different mitigation approaches. The flaw manifests when the parser miscalculates memory allocation parameters, resulting in a scenario where arbitrary data can be written beyond the intended buffer limits, potentially corrupting adjacent memory structures.
The operational impact of this vulnerability extends beyond simple application instability, as it creates potential attack vectors for remote code execution or system compromise. An attacker can craft a malicious document that, when opened by an unsuspecting user, will trigger the buffer overflow condition within the TextMaker application. This creates a typical social engineering attack scenario where user interaction is required to exploit the vulnerability, making it particularly dangerous in corporate or enterprise environments where users may encounter such documents through email attachments or shared network resources. The vulnerability's exploitation potential aligns with ATT&CK technique T1203, which covers exploitation for execution through malicious document files, and T1068, which addresses exploit for privilege escalation through application vulnerabilities.
Mitigation strategies for CVE-2020-13546 should prioritize immediate patching of the affected SoftMaker Office TextMaker 2021 software, as this represents the most effective defense against exploitation. Organizations should implement strict document validation policies that prevent automatic opening of untrusted documents, particularly those received through email or downloaded from unverified sources. Network-based security controls including email filtering and web proxies should be configured to block or quarantine suspicious document attachments. Additionally, system hardening measures such as address space layout randomization and data execution prevention should be enabled to reduce the effectiveness of potential exploitation attempts. Regular security awareness training for end users remains crucial in preventing successful social engineering attacks that leverage this vulnerability, as the requirement for user interaction makes human factors a critical component of overall security posture. The vulnerability demonstrates the importance of proper input validation and memory management practices in commercial software applications, highlighting the need for comprehensive security testing and code review processes during software development lifecycle.