CVE-2016-1713 in vTiger
Summary
by MITRE
Unrestricted file upload vulnerability in the Settings_Vtiger_CompanyDetailsSave_Action class in modules/Settings/Vtiger/actions/CompanyDetailsSave.php in Vtiger CRM 6.4.0 allows remote authenticated users to execute arbitrary code by uploading a crafted image file with an executable extension, then accessing it via a direct request to the file in test/logo/. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-6000.
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Analysis
by VulDB Data Team • 06/22/2024
The CVE-2016-1713 vulnerability represents a critical unrestricted file upload flaw in Vtiger CRM 6.4.0 that demonstrates how incomplete security fixes can leave systems exposed to persistent exploitation. This vulnerability specifically resides within the Settings_Vtiger_CompanyDetailsSave_Action class located in modules/Settings/Vtiger/actions/CompanyDetailsSave.php, making it accessible through the administrative settings interface. The flaw allows authenticated attackers to bypass file validation mechanisms by uploading malicious files with executable extensions disguised as image files, creating a dangerous pathway for code execution within the target environment.
The technical implementation of this vulnerability stems from inadequate file extension validation and content inspection within the company details saving functionality. When users upload company logos through the administrative interface, the application fails to properly verify file types beyond basic extension checks, permitting the upload of files with extensions like .php, .asp, or .jsp that are executable on the web server. This incomplete validation process creates a direct code execution vector because the system stores these files in the test/logo/ directory where they can be accessed directly via HTTP requests. The vulnerability operates under CWE-434 which categorizes unrestricted upload of executable files as a fundamental security flaw that enables arbitrary code execution through file upload mechanisms.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it provides attackers with a persistent foothold within the target environment. Once an attacker successfully uploads a malicious file, they can execute arbitrary code on the web server with the privileges of the web application, potentially leading to complete system compromise. The vulnerability's persistence is enhanced by the fact that it was introduced by an incomplete fix for CVE-2015-6000, indicating that security teams may have prematurely considered the issue resolved without addressing all attack vectors. This pattern of incomplete remediation creates a false sense of security and leaves organizations vulnerable to continued exploitation.
Attackers can exploit this vulnerability through a straightforward multi-step process that begins with authentication to the Vtiger CRM system, followed by uploading a crafted file through the company details settings interface, and concluding with direct HTTP access to execute the malicious code. The ATT&CK framework categorizes this as a file upload attack under the T1190 technique, where adversaries leverage web application vulnerabilities to upload malicious files that can then be executed. Organizations using Vtiger CRM 6.4.0 are particularly at risk because the vulnerability affects the administrative interface, meaning that even basic user accounts with appropriate permissions can potentially exploit this flaw. The impact is amplified by the fact that many organizations may not regularly monitor or audit their web application upload directories, making detection of such attacks more difficult.
Organizations should implement immediate mitigations including comprehensive file type validation that checks both file extensions and content signatures, proper file storage with restricted web access, and regular security audits of upload directories. The fix should address the root cause by implementing a robust file validation mechanism that rejects executable files regardless of their extensions, and by ensuring that uploaded files are stored outside of the web root or with appropriate access controls. Additionally, organizations should consider implementing web application firewalls to monitor and block suspicious file upload activities, and should establish regular security assessments to identify similar incomplete fixes that may exist in other components of their Vtiger CRM installations.