CVE-2018-3931 in Office Server
Summary
by MITRE
In Antenna House Office Server Document Converter version V6.1 Pro MR2 for Linux64 (6,1,2018,0312), a crafted Microsoft Word (DOC) document can lead to an out-of-bounds write, resulting in remote code execution. This vulnerability occurs in the `putShapeProperty` method.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability identified as CVE-2018-3931 affects Antenna House Office Server Document Converter version V6.1 Pro MR2 for Linux64, representing a critical security flaw that enables remote code execution through crafted Microsoft Word documents. This vulnerability specifically manifests within the `putShapeProperty` method, where improper input validation leads to memory corruption issues. The flaw exists in the document conversion process that handles Microsoft Word format files, making it particularly dangerous for environments that process untrusted document content.
The technical implementation of this vulnerability stems from inadequate bounds checking within the shape property handling mechanism of the document converter. When processing maliciously crafted DOC files, the `putShapeProperty` method fails to validate array indices or buffer boundaries, allowing an attacker to manipulate memory layout through carefully constructed input data. This out-of-bounds write condition creates a predictable memory corruption scenario that can be exploited to overwrite critical memory locations, potentially leading to arbitrary code execution. The vulnerability is classified under CWE-787, which represents out-of-bounds write conditions that can result in memory corruption and privilege escalation.
The operational impact of this vulnerability extends beyond simple document processing, as it creates a potential attack vector for remote code execution in systems that rely on the Antenna House converter for document format transformations. Attackers can leverage this flaw by delivering malicious Word documents to systems running the vulnerable software, potentially gaining unauthorized access to the underlying system. The risk is particularly elevated in environments where document conversion services are exposed to external users or untrusted sources, as the attack can be executed without requiring local system access or user interaction beyond opening the document.
Organizations should implement immediate mitigations including updating to patched versions of the Antenna House Office Server Document Converter, implementing network segmentation to limit exposure, and deploying intrusion detection systems to monitor for exploitation attempts. Additionally, input validation measures should be enhanced to restrict document processing from untrusted sources, and regular security assessments should be conducted to identify similar vulnerabilities in document processing components. This vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain code execution, and represents a classic example of how document parsing libraries can create attack surfaces for remote code execution.