CVE-2015-0877 in C-BOARD Moyuku
Summary
by MITRE
Unrestricted file upload vulnerability in app/lib/mlf.pl in C-BOARD Moyuku before 1.03b3 allows remote attackers to execute arbitrary code by uploading a file with a \0 character in its name.
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Analysis
by VulDB Data Team • 04/17/2018
The vulnerability identified as CVE-2015-0877 represents a critical unrestricted file upload flaw within the C-BOARD Moyuku web application version 1.03b2 and earlier. This vulnerability exists in the file processing component located at app/lib/mlf.pl, which handles file uploads without proper validation or sanitization of filenames. The specific condition that triggers this vulnerability involves the presence of a null character within the filename, a technique commonly exploited in various file upload attacks due to the way certain programming languages and systems process such input.
The technical exploitation of this vulnerability stems from inadequate input validation mechanisms within the file upload handler. When a malicious user uploads a file containing a null character in its name, the system fails to properly sanitize or reject such filenames, allowing the upload process to proceed. This flaw enables attackers to bypass normal file type restrictions and potentially execute arbitrary code on the target system. The null character injection technique is particularly dangerous because it can disrupt string processing functions and potentially lead to buffer overflows or other memory corruption issues that attackers can leverage for code execution.
From an operational impact perspective, this vulnerability creates significant security risks for organizations using affected versions of C-BOARD Moyuku. Remote attackers can leverage this flaw to upload malicious files that may contain shellcode, web shells, or other malicious payloads. Once uploaded, these files can be executed by the web server, providing attackers with unauthorized access to the system and potentially enabling full compromise of the affected server. The vulnerability affects the entire application stack since it operates at the file upload level, potentially allowing attackers to escalate privileges, steal sensitive data, or use the compromised system as a pivot point for further attacks within the network infrastructure.
The vulnerability aligns with CWE-434, which describes unrestricted file upload or upload of executable files, and demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the T1190 technique for Exploit Public-Facing Application. Organizations should implement immediate mitigations including updating to C-BOARD Moyuku version 1.03b3 or later, which contains the necessary patches to address this vulnerability. Additional protective measures include implementing strict filename validation that rejects files containing null characters or other special characters, configuring web server restrictions to prevent execution of uploaded files, and implementing proper input sanitization throughout the application. Network segmentation and monitoring solutions should also be deployed to detect suspicious file upload activities and prevent unauthorized access to the vulnerable system components.