CVE-2018-11637 in PowerMedia XMS
Summary
by MITRE
Information leakage vulnerability in the administrative console in Dialogic PowerMedia XMS through 3.5 allows remote attackers to read arbitrary files from the /var/ directory because a symlink exists under the web root.
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Analysis
by VulDB Data Team • 02/24/2020
The vulnerability identified as CVE-2018-11637 represents a critical information disclosure flaw within the Dialogic PowerMedia XMS administrative console version 3.5 and earlier. This vulnerability stems from improper file access controls that allow remote attackers to exploit a symbolic link present within the web root directory structure. The flaw specifically enables unauthorized access to sensitive files located within the /var/ directory, which typically contains system logs, configuration files, and other potentially sensitive data that should remain protected from external access. The vulnerability exists due to insufficient validation of file paths and inadequate restrictions on symbolic link resolution within the web application's file handling mechanisms.
The technical exploitation of this vulnerability occurs through a well-known path traversal attack vector that leverages the existence of a symbolic link under the web root directory. When an attacker crafts a specific request that references this symbolic link, the application fails to properly validate the requested file path, allowing the attacker to traverse the file system and access files in the /var/ directory. This type of vulnerability falls under the CWE-22 category of Path Traversal, which is classified as a common weakness in web applications that fail to properly validate user-supplied input. The attack vector operates by manipulating the application's file resolution process to bypass normal access controls and gain access to restricted system directories.
The operational impact of this vulnerability extends beyond simple information disclosure, as the /var/ directory often contains critical system information that could be leveraged for further attacks. Sensitive data such as system logs, configuration files, and potentially database credentials or encryption keys may be accessible to remote attackers. This information leakage could enable attackers to conduct reconnaissance activities, identify system vulnerabilities, or extract credentials that could lead to privilege escalation. The remote nature of the attack means that an attacker does not require physical access to the system or local network credentials to exploit this vulnerability, making it particularly dangerous in publicly accessible environments. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing for Information) as attackers can systematically enumerate and extract sensitive information from the compromised system.
Organizations affected by this vulnerability should implement immediate mitigations including removing or securing the problematic symbolic link within the web root directory, implementing proper input validation and sanitization for all file access operations, and restricting file system access permissions for the web application. The recommended approach involves ensuring that all file path resolution operations properly validate and sanitize user input to prevent traversal attacks, while also implementing proper access controls that restrict web application access to system directories. Additionally, security hardening measures should include regular security audits of web application file access mechanisms, implementation of web application firewalls, and ensuring that all system components are updated to the latest security patches provided by Dialogic. The vulnerability demonstrates the critical importance of proper file system access controls and input validation in preventing information disclosure attacks that can compromise entire system infrastructures.