CVE-2022-44544 in Mahara
Summary
by MITRE • 11/06/2022
Mahara 21.04 before 21.04.7, 21.10 before 21.10.5, 22.04 before 22.04.3, and 22.10 before 22.10.0 potentially allow a PDF export to trigger a remote shell if the site is running on Ubuntu and the flag -dSAFER is not set with Ghostscript.
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Analysis
by VulDB Data Team • 05/03/2025
This vulnerability exists within the Mahara learning management system where improper handling of PDF exports creates a remote code execution vector. The flaw specifically affects versions prior to the mentioned patched releases across multiple version branches including 21.04, 21.10, 22.04, and 22.10. The vulnerability is particularly concerning because it leverages the Ghostscript rendering engine which is commonly used for PDF processing within the system. When Mahara generates PDF exports, it relies on Ghostscript to handle the conversion process, creating a potential attack surface where malicious PDF content could be crafted to exploit the underlying rendering engine.
The technical mechanism of this vulnerability involves the interaction between Mahara's PDF export functionality and Ghostscript's command-line parameters. The vulnerability specifically requires that the system be running on Ubuntu and that Ghostscript be executed without the -dSAFER flag. The -dSAFER flag is a security parameter that restricts Ghostscript's access to the local file system and prevents execution of potentially dangerous commands. Without this flag, Ghostscript becomes vulnerable to command injection attacks through specially crafted PDF files that contain malicious PostScript code. This PostScript code can exploit the lack of sandboxing to execute arbitrary commands on the server hosting the Mahara instance.
The operational impact of this vulnerability is severe as it allows remote attackers to achieve full system compromise without requiring authentication or prior access to the system. Attackers could potentially upload malicious PDF files or manipulate existing content to trigger the vulnerable code path during PDF generation. Once exploited, the remote shell access would provide attackers with complete control over the server, enabling them to exfiltrate sensitive data, install backdoors, modify system configurations, or use the compromised system as a pivot point for further attacks within the network. The vulnerability affects not just individual user data but could potentially compromise entire institutional learning management systems.
The vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic command injection flaw. From an ATT&CK framework perspective, this maps to T1059.007 for command and scripting interpreter, specifically the use of bash or shell commands, and T1190 for exploit for information disclosure. Organizations should immediately apply the security patches released by Mahara for versions 21.04.7, 21.10.5, 22.04.3, and 22.10.0 to address this vulnerability. Additionally, system administrators should review Ghostscript configurations to ensure the -dSAFER flag is properly implemented and consider implementing network segmentation and monitoring to detect potential exploitation attempts. The vulnerability highlights the importance of proper input validation and sandboxing in third-party library integrations, particularly when dealing with document processing and rendering components.