CVE-2018-3929 in Office Server
Summary
by MITRE
An exploitable heap corruption exists in the PowerPoint document conversion functionality of the Antenna House Office Server Document Converter version V6.1 Pro MR2 for Linux64 (6,1,2018,0312). A crafted PowerPoint (PPT) document can lead to heap corruption, resulting in remote code execution.
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Analysis
by VulDB Data Team • 04/06/2023
The vulnerability identified as CVE-2018-3929 represents a critical heap corruption flaw within the Antenna House Office Server Document Converter version V6.1 Pro MR2 for Linux64 systems. This vulnerability specifically targets the PowerPoint document conversion functionality, making it particularly dangerous in environments where document conversion services are exposed to untrusted input. The flaw enables remote code execution through carefully crafted PowerPoint files that trigger memory corruption during the conversion process, potentially allowing attackers to execute arbitrary code on the affected system. The vulnerability exists in the handling of PPT files during the conversion to other document formats, where improper memory management leads to heap corruption that can be exploited remotely. This issue affects organizations relying on the Antenna House Office Server for document processing tasks, particularly those operating in cloud environments or serving external users with document conversion services.
The technical exploitation of this vulnerability stems from improper input validation and memory handling within the document conversion engine. When processing maliciously crafted PowerPoint files, the converter fails to properly validate the structure and content of the PPT document, leading to heap-based buffer overflows or memory corruption patterns. The flaw typically manifests during the parsing of specific PowerPoint elements or metadata within the document structure, where the conversion process attempts to allocate or manipulate memory regions without adequate bounds checking. This type of vulnerability aligns with CWE-122 Heap-based Buffer Overflow, which describes insufficient validation of buffer bounds during heap memory operations. The attacker can craft a PPT file that, when processed by the converter, causes the application to write beyond allocated memory boundaries, potentially overwriting critical memory structures or function pointers. The vulnerability's remote execution capability indicates that the conversion service is accessible over network connections, allowing attackers to submit malicious documents without physical access to the system.
The operational impact of CVE-2018-3929 extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within affected networks. Organizations utilizing the Antenna House Office Server for document conversion services face significant risk, particularly in cloud environments or shared hosting scenarios where the service may be exposed to external threats. Successful exploitation could allow attackers to gain full control over the affected server, potentially leading to data exfiltration, persistent backdoor installation, or use as a pivot point for attacking other systems within the network. The vulnerability's presence in a document conversion service makes it particularly attractive to threat actors, as it can be exploited through legitimate document submission channels without requiring advanced privileges or specialized access. This makes the attack surface significantly larger compared to vulnerabilities requiring direct system access or physical presence. Network-based attacks can be executed through simple document upload mechanisms, making this vulnerability particularly dangerous in multi-tenant environments or public document processing services.
Mitigation strategies for CVE-2018-3929 should focus on immediate patching and network segmentation approaches to limit the attack surface. Organizations must prioritize updating their Antenna House Office Server installations to versions that address this heap corruption vulnerability, as the vendor has likely released security patches to correct the memory handling issues. Network segmentation and access controls should be implemented to restrict access to the document conversion service, limiting exposure to only trusted internal users and applications. Input validation measures should be strengthened at the service level, including implementing strict file format validation and content scanning for potentially malicious PowerPoint documents. Security monitoring should be enhanced to detect unusual document processing patterns or attempts to submit suspicious files to the conversion service. The vulnerability's classification under ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell suggests that exploitation may involve command execution capabilities, making defensive measures such as PowerShell logging and execution policy enforcement relevant. Additionally, implementing application whitelisting and restricting the execution of unknown document conversion processes can help prevent exploitation of this vulnerability. Regular security assessments of document processing services and maintaining up-to-date threat intelligence on similar vulnerabilities in office document conversion tools should form part of the overall security posture to prevent similar issues from arising in the future.