CVE-2018-18912 in Web Server
Summary
by MITRE
An issue was discovered in Easy File Sharing (EFS) Web Server 7.2. A stack-based buffer overflow vulnerability occurs when a malicious POST request has been made to forum.ghp upon creating a new topic in the forums, which allows remote attackers to execute arbitrary code.
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Analysis
by VulDB Data Team • 09/17/2023
The vulnerability identified as CVE-2018-18912 represents a critical stack-based buffer overflow flaw within Easy File Sharing Web Server version 7.2 that fundamentally compromises the integrity and security of the affected system. This vulnerability specifically manifests when processing maliciously crafted POST requests targeted at the forum.ghp endpoint during the creation of new topics within the forums functionality, creating a dangerous attack surface that remote adversaries can exploit to gain unauthorized control over the affected server.
The technical implementation of this vulnerability stems from inadequate input validation and memory management practices within the web server's forum handling component. When a malicious user submits a specially crafted POST request containing oversized data to the forum.ghp endpoint, the application fails to properly bounds-check the incoming data before copying it into a fixed-size stack buffer. This failure creates a classic stack-based buffer overflow condition where the excessive data overflows into adjacent memory locations, potentially corrupting the stack frame and allowing attackers to overwrite critical program execution elements including return addresses and function pointers.
From an operational perspective, this vulnerability presents a severe threat to organizations relying on Easy File Sharing Web Server 7.2 as it enables remote code execution without requiring any authentication credentials. Attackers can leverage this flaw to execute arbitrary commands on the target system with the privileges of the web server process, potentially leading to complete system compromise. The vulnerability's accessibility through simple HTTP POST requests means that exploitation can occur from any network location, making it particularly dangerous for publicly accessible web servers. The impact extends beyond immediate system compromise to include potential data exfiltration, service disruption, and establishment of persistent backdoors within the network infrastructure.
Security professionals should recognize this vulnerability as aligning with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions. The attack vector follows patterns consistent with techniques documented in the MITRE ATT&CK framework under the T1059.007 sub-technique for Command and Scripting Interpreter: PowerShell, as attackers may use the remote execution capability to deploy additional malicious tools or establish persistence mechanisms. Organizations should implement immediate mitigations including applying vendor patches, implementing web application firewalls to filter suspicious POST requests, and conducting comprehensive security assessments of all web server components. The vulnerability also highlights the importance of input validation practices and proper memory management in web applications, serving as a reminder that even seemingly simple functionalities like forum topic creation can contain critical security flaws when not properly secured against buffer overflow attacks.