CVE-2014-3791 in Easy File Sharing Web Server
Summary
by MITRE
Stack-based buffer overflow in Easy File Sharing (EFS) Web Server 6.8 allows remote attackers to execute arbitrary code via a long string in a cookie UserID parameter to vfolder.ghp.
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Analysis
by VulDB Data Team • 08/03/2025
The vulnerability identified as CVE-2014-3791 represents a critical stack-based buffer overflow flaw within the Easy File Sharing Web Server version 6.8. This issue manifests in the handling of HTTP cookie parameters, specifically targeting the UserID field within the vfolder.ghp endpoint. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize or limit the length of user-supplied data before processing it within the server's memory stack structure. The flaw enables remote attackers to craft malicious HTTP requests containing excessively long strings in the UserID cookie parameter, which subsequently triggers a buffer overflow condition that can be exploited to execute arbitrary code on the affected system. This type of vulnerability falls under the common weakness enumeration CWE-121, which categorizes stack-based buffer overflow conditions as a fundamental memory safety issue that occurs when data written to a stack buffer exceeds the buffer's allocated size.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it provides attackers with potential full system compromise. When a remote attacker successfully exploits this buffer overflow, they can overwrite adjacent memory locations including return addresses, function pointers, and other critical program state information. This memory corruption can lead to unpredictable program behavior, system crashes, or more dangerously, allow attackers to inject and execute malicious shellcode that could provide them with unauthorized access to the server. The vulnerability is particularly concerning because it requires no authentication to exploit, making it a remote code execution vulnerability that can be leveraged by attackers from anywhere on the internet. The attack vector specifically targets the web server's cookie handling mechanism, which is a fundamental component of web application security and session management.
Security professionals should consider this vulnerability in the context of the attack chain framework where it would typically appear as an initial access point or privilege escalation mechanism. The exploitation process involves crafting a malicious HTTP request with an oversized cookie value that triggers the buffer overflow during normal server processing operations. This type of vulnerability is classified under the attack technique T1059 in the MITRE ATT&CK framework, specifically related to command and script injection techniques. Organizations running Easy File Sharing Web Server 6.8 should immediately implement mitigations including input validation, parameter length restrictions, and application firewalls to prevent exploitation attempts. The recommended approach involves applying vendor patches or upgrading to newer versions of the software, as well as implementing network-level protections such as intrusion detection systems that can identify and block malicious cookie values. Additionally, regular security assessments and penetration testing should be conducted to identify similar buffer overflow vulnerabilities in other web server components and applications that may be running on the same infrastructure.
The technical implementation of this vulnerability demonstrates how seemingly simple input handling can create catastrophic security implications. The buffer overflow occurs because the server's code does not perform bounds checking on the UserID cookie value before copying it into a fixed-size stack buffer. This allows attackers to write data beyond the allocated memory boundaries, potentially overwriting critical program execution flow information. The vulnerability's exploitability is enhanced by the fact that it operates over standard HTTP protocols and requires no special privileges or local access. Organizations should consider implementing comprehensive security measures including regular software updates, security code reviews, and robust input validation practices to prevent similar vulnerabilities from occurring in their own applications and systems. The presence of such vulnerabilities in widely deployed web server software highlights the importance of maintaining up-to-date security patches and conducting thorough security assessments of all network-facing applications to prevent exploitation by threat actors.