CVE-2015-4670 in AJAX Control Toolkit
Summary
by MITRE
Directory traversal vulnerability in the AjaxFileUpload control in DevExpress AJAX Control Toolkit (aka AjaxControlToolkit) before 15.1 allows remote attackers to write to arbitrary files via a .. (dot dot) in the fileId parameter to AjaxFileUploadHandler.axd.
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Analysis
by VulDB Data Team • 10/18/2017
The vulnerability identified as CVE-2015-4670 represents a critical directory traversal flaw within the DevExpress AJAX Control Toolkit's AjaxFileUpload control component. This vulnerability exists in versions prior to 15.1 and specifically affects the AjaxFileUploadHandler.axd endpoint which processes file upload operations. The flaw stems from insufficient input validation and sanitization of the fileId parameter, allowing malicious actors to manipulate file paths through the use of directory traversal sequences. The vulnerability is classified under CWE-22 as a directory traversal attack, where attackers can exploit weak input validation to access or manipulate files outside the intended directory structure.
The technical exploitation of this vulnerability occurs when an attacker submits a specially crafted fileId parameter containing .. (dot dot) sequences to the AjaxFileUploadHandler.axd endpoint. These sequences enable attackers to navigate upward through the directory hierarchy and write files to arbitrary locations on the server filesystem. The flaw essentially bypasses normal file upload restrictions and validation mechanisms, allowing unauthorized file system modifications. This type of vulnerability is particularly dangerous in web applications where file upload functionality is exposed to untrusted users, as it can lead to complete system compromise through file injection attacks.
From an operational perspective, this vulnerability presents significant risk to organizations utilizing DevExpress AJAX Control Toolkit in their web applications. Attackers could leverage this flaw to upload malicious files such as web shells, backdoors, or other harmful payloads to critical system locations. The impact extends beyond simple file manipulation as it can enable attackers to execute arbitrary code, escalate privileges, and potentially gain full control over the affected web server. The vulnerability's remote nature means that exploitation does not require local system access, making it particularly attractive to attackers who can target exposed web applications from external networks.
The security implications of CVE-2015-4670 align with ATT&CK technique T1059.007 for command and script injection, as successful exploitation can lead to arbitrary code execution. Organizations should implement immediate mitigations including upgrading to DevExpress AJAX Control Toolkit version 15.1 or later, which contains the necessary patches to prevent directory traversal attacks. Additional protective measures include implementing strict input validation for all file upload parameters, configuring proper file system permissions to limit write access to upload directories, and deploying web application firewalls to detect and block malicious file upload attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the application stack. The vulnerability demonstrates the critical importance of validating user inputs and implementing proper access controls in web applications, particularly those handling file operations.