CVE-2013-10034 in KServer
Summary
by MITRE • 07/31/2025
An unrestricted file upload vulnerability exists in Kaseya KServer versions prior to 6.3.0.2. The uploadImage.asp endpoint allows unauthenticated users to upload files to arbitrary paths via a crafted filename parameter in a multipart/form-data POST request. Due to the lack of authentication and input sanitation, an attacker can upload a file with an .asp extension to a web-accessible directory, which can then be invoked to execute arbitrary code with the privileges of the IUSR account. The vulnerability enables remote code execution without prior authentication and was resolved in version 6.3.0.2 by removing the vulnerable uploadImage.asp endpoint.
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Analysis
by VulDB Data Team • 07/31/2025
The vulnerability identified as CVE-2013-10034 represents a critical unrestricted file upload flaw in Kaseya KServer software prior to version 6.3.0.2. This weakness resides within the uploadImage.asp endpoint which fails to implement proper authentication mechanisms or input validation controls. The vulnerability operates by accepting multipart/form-data POST requests containing a filename parameter that can be manipulated by unauthenticated attackers to specify arbitrary file paths for upload operations. The absence of proper access controls and sanitization measures creates a pathway for malicious actors to bypass security restrictions and place malicious files directly into web-accessible directories. This flaw directly aligns with CWE-434 which categorizes unrestricted file uploads as a significant security concern due to the potential for arbitrary code execution through malicious file placement.
The technical exploitation of this vulnerability enables remote code execution through a straightforward attack vector that requires no prior authentication credentials. Attackers can craft malicious requests that upload files with .asp extensions to web-accessible directories, leveraging the web server's ability to process and execute asp scripts. The uploaded files execute with the privileges of the IUSR account, which typically represents the identity under which the web server operates and may have limited but potentially exploitable permissions within the system. The vulnerability's impact extends beyond simple file upload capabilities as it creates a persistent backdoor mechanism that can be used for ongoing system compromise and data exfiltration. This represents a classic example of how insufficient input validation combined with weak authentication can create severe security implications that directly violate the principle of least privilege.
The operational consequences of this vulnerability are particularly severe as it enables attackers to gain unauthorized access to systems without requiring legitimate credentials or prior exploitation of other vulnerabilities. The ability to upload and execute arbitrary code through a simple HTTP POST request makes this vulnerability highly attractive to attackers and significantly reduces the attack surface complexity. Organizations using affected Kaseya versions face potential system compromise, data breaches, and unauthorized access to sensitive information. The vulnerability's persistence is enhanced by the fact that uploaded files remain accessible until manually removed, providing attackers with long-term access to compromised systems. This type of vulnerability is often categorized under ATT&CK technique T1190 which describes the use of unauthorized access to establish persistence and maintain control over compromised systems. The lack of authentication requirements makes this vulnerability particularly dangerous as it can be exploited by anyone with network access to the affected system.
Mitigation strategies for CVE-2013-10034 focus primarily on upgrading to Kaseya KServer version 6.3.0.2 or later where the vulnerable uploadImage.asp endpoint has been removed from the software. Organizations should also implement additional security controls including network segmentation to limit access to vulnerable endpoints, implementing web application firewalls to filter suspicious upload requests, and conducting thorough network monitoring for unusual file upload activities. Security teams should perform comprehensive vulnerability assessments to identify any other potentially vulnerable endpoints within the system and ensure proper input validation is implemented across all file upload mechanisms. The remediation process should include disabling or removing the vulnerable endpoint entirely and implementing proper authentication controls for all file upload operations. Organizations should also consider implementing file type validation, content verification, and secure file storage practices to prevent similar vulnerabilities from occurring in other applications within their infrastructure.