CVE-2018-19586 in Silverpeas
Summary
by MITRE
Silverpeas 5.15 through 6.0.2 is affected by an authenticated Directory Traversal vulnerability that can be triggered during file uploads because core/webapi/upload/FileUploadData.java mishandles a StringUtil.java call. This vulnerability enables regular users to write arbitrary files on the underlying system with privileges of the user running the application. Especially, an attacker may leverage the vulnerability to write an executable JSP file in an exposed web directory to execute commands on the underlying system.
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Analysis
by VulDB Data Team • 08/28/2023
The vulnerability identified as CVE-2018-19586 affects Silverpeas versions 5.15 through 6.0.2, representing a critical authenticated directory traversal flaw that fundamentally undermines the application's file handling security mechanisms. This vulnerability exists within the core web API upload functionality, specifically in the FileUploadData.java component which improperly processes file path manipulation through calls to StringUtil.java. The flaw allows authenticated users to exploit a path traversal condition that bypasses normal file system access controls and validation mechanisms.
The technical implementation of this vulnerability stems from insufficient input validation and path sanitization within the file upload process. When users upload files through the web interface, the application fails to properly sanitize file paths, allowing maliciously crafted filenames to traverse directory structures. This misconfiguration enables attackers to write files to arbitrary locations on the server's file system, potentially gaining write access to critical directories including web application root folders. The vulnerability is particularly dangerous because it operates with the privileges of the application user, which often runs with elevated permissions on the hosting system.
The operational impact of this vulnerability extends beyond simple unauthorized file writing, creating a potential command execution vector that could compromise the entire system. An attacker with valid credentials can leverage this weakness to upload malicious JSP files to exposed web directories, effectively creating a backdoor for remote code execution. This scenario aligns with CWE-22 Directory Traversal vulnerability classification, which specifically addresses improper handling of file paths that allows access to files outside the intended directory structure. The attack pattern follows typical exploitation techniques described in the MITRE ATT&CK framework under the T1105 command and control communication and T1059 command and control protocols categories.
Organizations running affected Silverpeas versions face significant security risks including potential data breaches, system compromise, and unauthorized access to sensitive information. The vulnerability affects any authenticated user with upload privileges, making it particularly concerning for collaborative environments where multiple users have access to file upload functionality. The privilege escalation aspect of this vulnerability means that even users with limited permissions can potentially gain system-level access through the uploaded malicious files.
Mitigation strategies should include immediate patching of the affected Silverpeas versions to the latest secure releases that address the directory traversal flaw. Additionally, implementing proper input validation and sanitization measures within the file upload components is essential, including strict file path validation and ensuring that uploaded files cannot traverse beyond designated directories. Network segmentation and access control measures should be enforced to limit user privileges and reduce the potential impact of successful exploitation. Regular security assessments and code reviews focusing on file handling operations can help identify similar vulnerabilities in other applications and systems. The remediation process should also include monitoring for unauthorized file uploads and implementing automated scanning for malicious file patterns in uploaded content.