CVE-2018-3983 in Word Processor
Summary
by MITRE
An exploitable uninitialized pointer vulnerability exists in the Word document parser of the the Atlantis Word Processor. A specially crafted document can cause an array fetch to return an uninitialized pointer and then performs some arithmetic before writing a value to the result. Usage of this uninitialized pointer can allow an attacker to corrupt heap memory resulting in code execution under the context of the application. An attacker must convince a victim to open a document in order to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/01/2024
The vulnerability identified as CVE-2018-3983 represents a critical heap corruption issue within the Atlantis Word Processor's document parsing functionality. This flaw manifests as an uninitialized pointer vulnerability that occurs during the processing of Microsoft Word documents, specifically when the application attempts to parse malformed or specially crafted document structures. The vulnerability resides in the word processor's parser component responsible for interpreting document formats and extracting content for display and manipulation.
The technical exploitation of this vulnerability begins with the parser encountering a malformed document structure that triggers an array fetch operation returning an uninitialized pointer value. This uninitialized pointer, which contains arbitrary data from the program's memory heap, undergoes subsequent arithmetic operations before being used as a memory address for writing data. The fundamental flaw lies in the absence of proper initialization checks for pointer variables, creating a scenario where the application operates on unpredictable memory locations. This behavior directly correlates to CWE-457, which describes the use of uninitialized variables, and represents a classic heap-based memory corruption vulnerability.
The operational impact of this vulnerability extends beyond simple application instability, as it provides attackers with the capability to achieve arbitrary code execution within the context of the Atlantis Word Processor application. When an attacker successfully triggers this vulnerability, they can manipulate heap memory layout to overwrite critical program structures or inject malicious code into the application's memory space. The privilege escalation aspect is particularly concerning as the execution occurs under the same user context as the vulnerable application, potentially allowing attackers to execute malicious payloads with the application's permissions and access rights. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands through the compromised application.
The attack vector requires social engineering to convince victims to open the malicious document, making this vulnerability particularly dangerous in enterprise environments where users frequently encounter and open various document types. The document-based nature of the attack means that the vulnerability can be delivered through email attachments, shared network drives, or other document distribution channels. Once opened, the vulnerable application automatically processes the malicious document structure, triggering the uninitialized pointer dereference and subsequent heap corruption. Organizations should implement comprehensive security measures including email filtering, document validation, and application whitelisting to mitigate the risk of exploitation. The vulnerability demonstrates the importance of proper memory management practices and input validation in document processing applications, as well as the critical need for regular security updates and patches to address such memory corruption vulnerabilities that could lead to complete system compromise.