CVE-2018-12940 in SeedDMS
Summary
by MITRE
Unrestricted file upload vulnerability in "op/op.UploadChunks.php" in SeedDMS (formerly LetoDMS and MyDMS) before 5.1.8 allows remote attackers to execute arbitrary code by uploading a file with an executable extension specified by the "qqfile" parameter. This allows an authenticated attacker to upload a malicious file containing PHP code to execute operating system commands to the web root of the application.
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Analysis
by VulDB Data Team • 04/27/2023
The CVE-2018-12940 vulnerability represents a critical unrestricted file upload flaw in SeedDMS version 5.1.7 and earlier, which was formerly known as LetoDMS and MyDMS. This vulnerability resides in the op/op.UploadChunks.php component and specifically targets the application's file upload functionality. The flaw allows authenticated attackers to bypass security controls by uploading malicious files with executable extensions through the qqfile parameter, creating a significant vector for remote code execution within the web application's environment.
The technical implementation of this vulnerability stems from inadequate input validation and file extension filtering mechanisms within the SeedDMS file upload system. When an authenticated user submits a file through the qqfile parameter, the application fails to properly validate the file type or content, allowing attackers to upload files with extensions such as .php, .phtml, or other executable formats. The vulnerability is particularly dangerous because it operates within the web root directory, meaning that successful uploads can directly execute malicious code on the target system without requiring additional exploitation steps.
This vulnerability directly maps to CWE-434, which describes the weakness of unrestricted upload of file with dangerous type, and aligns with ATT&CK technique T1190, representing the use of exploit for execution through web shell deployment. The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to establish persistent access, escalate privileges, and potentially compromise the entire web server. Attackers can leverage this vulnerability to upload web shells, backdoors, or other malicious payloads that can be used for data exfiltration, lateral movement, or maintaining unauthorized access to the compromised system.
The exploitation process requires authentication, which limits the attack surface compared to fully unauthenticated vulnerabilities, but still represents a significant risk to organizations where user access is granted to the document management system. Once authenticated, attackers can upload malicious PHP files that execute arbitrary operating system commands, potentially leading to complete system compromise. The vulnerability affects organizations using SeedDMS versions prior to 5.1.8, making it crucial for administrators to assess their current deployment status and implement immediate remediation measures.
Organizations should prioritize patching their SeedDMS installations to version 5.1.8 or later, which includes proper file type validation and restriction mechanisms. Additional mitigations include implementing strict file extension filtering, disabling executable file uploads, and deploying web application firewalls to monitor and block suspicious upload attempts. Security teams should also conduct regular vulnerability assessments of their document management systems and implement proper access controls to limit the number of authenticated users with upload privileges. The vulnerability demonstrates the critical importance of input validation and proper security controls in web applications, particularly those handling user-uploaded content.