CVE-2013-3425 in WebEx
Summary
by MITRE
The Meeting Center component in Cisco WebEx 11 generates different error messages for invalid file-access attempts depending on whether a file exists, which allows remote authenticated users to enumerate files via a series of SPI calls, aka Bug ID CSCuc35965.
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Analysis
by VulDB Data Team • 05/17/2018
The vulnerability identified as CVE-2013-3425 resides within the Meeting Center component of Cisco WebEx 11, representing a classic information disclosure flaw that stems from inconsistent error handling mechanisms. This weakness manifests when the system provides different error responses based on whether a requested file actually exists on the server, creating a predictable pattern that adversaries can exploit for reconnaissance purposes. The vulnerability specifically affects remote authenticated users who possess valid credentials to access the WebEx platform, making it particularly concerning as it leverages legitimate user access to perform unauthorized enumeration activities. The underlying issue demonstrates poor security design principles where the system's response to invalid requests reveals sensitive information about the underlying file structure, effectively acting as a fingerprinting mechanism for attackers.
The technical exploitation of this vulnerability occurs through a series of Structured Programming Interface (SPI) calls that allow an authenticated user to systematically test file access permissions across the target system. When a user attempts to access a file that exists, the system returns one type of error message, whereas attempting to access a non-existent file generates a different response. This differential behavior creates a side-channel attack vector that enables attackers to determine the existence of specific files without requiring direct access to their contents. The flaw operates at the application layer and specifically impacts the file access control mechanisms within the Meeting Center component, which is designed to facilitate collaborative meeting environments but inadvertently exposes directory structure information through its error handling routines. This vulnerability type aligns with CWE-200, which describes improper exposure of sensitive information, and represents a clear violation of the principle of least privilege.
The operational impact of CVE-2013-3425 extends beyond simple file enumeration, as it provides attackers with valuable reconnaissance data that can be used to plan more sophisticated attacks against the WebEx environment. Once an attacker has mapped the file structure, they can identify sensitive files, configuration data, or potentially vulnerable components within the system. The vulnerability enables a form of directory traversal enumeration that can reveal the presence of backup files, temporary data, or other system artifacts that might contain additional security weaknesses. This information disclosure can be particularly damaging in enterprise environments where WebEx is used for sensitive business communications, as it allows attackers to understand the scope of potential targets and identify high-value assets within the system. The impact is amplified when considering that this vulnerability affects a collaborative platform that may contain confidential meeting materials, proprietary information, or sensitive business data.
Mitigation strategies for CVE-2013-3425 should focus on implementing consistent error handling throughout the application to prevent information leakage through differential responses. Organizations should ensure that all file access attempts, regardless of whether the file exists, return identical error messages that do not reveal system structure information. The implementation of proper access controls and input validation mechanisms can significantly reduce the attack surface, while regular security audits should be conducted to identify similar inconsistencies in error handling across the application. System administrators should also consider implementing additional monitoring and logging mechanisms to detect unusual patterns of file access attempts that may indicate enumeration activities. According to ATT&CK framework, this vulnerability relates to T1083 (File and Directory Discovery) and T1566 (Phishing), as it enables initial reconnaissance activities that can lead to more advanced exploitation techniques. Cisco has addressed this vulnerability through software updates and patches that standardize the error responses, emphasizing the importance of maintaining up-to-date security controls to prevent such information disclosure scenarios. The vulnerability serves as a reminder of the critical need for consistent security practices in application development, particularly in error handling and user access control mechanisms.