CVE-2020-4476 in Sterling File Gateway
Summary
by MITRE • 11/16/2020
IBM Sterling File Gateway 2.2.0.0 through 2.2.6.5 and 6.0.0.0 through 6.0.3.2 could allow a remote attacker to obtain sensitive information when a detailed technical error message is returned in the browser. This information could be used in further attacks against the system. IBM X-Force ID: 181778.
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Analysis
by VulDB Data Team • 12/07/2020
The vulnerability identified as CVE-2020-4476 affects IBM Sterling File Gateway versions within the 2.2.0.0 through 2.2.6.5 and 6.0.0.0 through 6.0.3.2 release ranges, representing a significant security weakness that exposes sensitive system information through improper error handling mechanisms. This flaw constitutes a critical information disclosure vulnerability that can be exploited by remote attackers without authentication, making it particularly dangerous in enterprise environments where file gateway systems handle sensitive data transfers and communications.
The technical flaw manifests when the system generates detailed technical error messages that are returned directly to the web browser interface during processing failures or system exceptions. These error messages contain sensitive information including system paths, internal component names, version identifiers, and potentially database connection details that should remain hidden from external users. The vulnerability stems from inadequate input validation and error handling procedures within the application's web interface, allowing attackers to intercept and analyze these verbose error responses to gain insights into the underlying system architecture and configuration.
From an operational impact perspective, this vulnerability creates multiple attack vectors for threat actors seeking to compromise the affected systems. The disclosed information can be leveraged to craft more sophisticated attacks by identifying specific system components that may have additional vulnerabilities, understanding the system's internal structure, and potentially exploiting other weaknesses in the same application stack. The exposure of version information also enables attackers to target known exploits specific to those IBM Sterling File Gateway releases, significantly increasing the attack surface and potential damage. Security analysts should note this vulnerability aligns with CWE-209, which specifically addresses "Information Exposure Through an Error Message" and represents a classic example of how poor error handling can lead to information disclosure.
The exploitation of this vulnerability follows standard attack patterns where remote attackers first probe the system to trigger error conditions, then analyze the returned error messages to gather intelligence for subsequent attacks. This type of information disclosure attack can be particularly effective when combined with other reconnaissance techniques, as the gathered information provides attackers with a roadmap for targeting specific components within the Sterling File Gateway system. Organizations should consider this vulnerability in the context of ATT&CK technique T1083, which covers "File and Directory Discovery" and T1068, "Exploitation for Privilege Escalation" as the information gathered can facilitate more targeted exploitation attempts.
Effective mitigation strategies include implementing proper error handling mechanisms that sanitize error messages before display, configuring the application to return generic error responses to users while logging detailed technical information internally for administrative purposes, and ensuring that system version information is not exposed through web interfaces. Organizations should also consider implementing web application firewalls to filter potentially malicious requests that could trigger these error conditions, and establish monitoring procedures to detect unusual error message patterns that might indicate exploitation attempts. Regular security updates and patches from IBM should be applied immediately to address this vulnerability, as the affected versions represent a window of opportunity for attackers to exploit the information disclosure weakness. The vulnerability also highlights the importance of following secure coding practices and conducting regular security assessments to identify similar error handling issues across the entire application stack.