CVE-2020-28587 in Office PlanMaker
Summary
by MITRE • 02/24/2021
A specially crafted document can cause the document parser to copy data from a particular record type into a static-sized buffer within an object that is smaller than the size used for the copy, which will cause a heap-based buffer overflow. An attacker can entice the victim to open a document to trigger this vulnerability. This affects SoftMaker Software GmbH SoftMaker Office PlanMaker 2021 (Revision 1014).
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Analysis
by VulDB Data Team • 03/04/2021
This vulnerability represents a classic heap-based buffer overflow condition that occurs within the document parsing functionality of SoftMaker Office PlanMaker 2021. The flaw manifests when the application processes specially crafted documents that contain records with specific data structures. The vulnerability stems from improper bounds checking during data copying operations where the parser attempts to copy data from a record type into a statically allocated buffer that is insufficient in size to accommodate the source data. This type of vulnerability falls under CWE-121, heap-based buffer overflow, which is categorized as a memory safety error that can lead to arbitrary code execution. The issue is particularly concerning because it operates within the context of document parsing, making it highly exploitable through social engineering attacks that trick users into opening malicious files.
The technical implementation of this vulnerability involves the document parser's handling of structured data records where the application fails to validate the size of incoming data against the destination buffer capacity. When a record type contains more data than the allocated static buffer can accommodate, the excess data overflows into adjacent memory locations, potentially corrupting other data structures or executable code within the application's heap memory space. This memory corruption can result in unpredictable behavior, application crashes, or more critically, provide attackers with opportunities to execute arbitrary code with the privileges of the victim user. The vulnerability is particularly dangerous in the context of office productivity software because users frequently open documents from untrusted sources, creating numerous attack vectors for exploitation.
The operational impact of this vulnerability extends beyond simple application instability to potentially enable full system compromise. An attacker who successfully exploits this vulnerability could gain remote code execution capabilities, allowing them to install malware, steal sensitive data, or establish persistence within the victim's system. The attack vector is particularly insidious because it requires minimal user interaction beyond opening a malicious document, making it susceptible to phishing campaigns and other social engineering techniques. This vulnerability affects the specific version mentioned and likely impacts other versions of SoftMaker Office PlanMaker that share similar parsing logic, creating a broad attack surface for potential exploitation.
Mitigation strategies should focus on immediate patching of the affected software version to address the buffer overflow condition in the document parser. Users should implement strict document handling policies, including disabling automatic execution of macros and implementing sandboxing techniques for document processing. Network-level defenses should include content filtering solutions that can identify and block suspicious document formats before they reach end-user systems. Additionally, regular security awareness training for users can help reduce the risk of successful social engineering attacks that leverage this vulnerability. Organizations should also consider implementing application whitelisting controls to restrict execution of untrusted document processing applications. The vulnerability demonstrates the critical importance of proper input validation and memory management practices in preventing buffer overflow exploits, aligning with ATT&CK technique T1203 for legitimate credential use and T1059 for command and scripting interpreter usage in exploitation scenarios.