CVE-2021-20563 in Sterling File Gateway
Summary
by MITRE • 09/24/2021
IBM Sterling File Gateway 2.2.0.0 through 6.1.0.3 could allow a remote authenciated user to obtain sensitive information. By sending a specially crafted request, the user could disclose a valid filepath on the server which could be used in further attacks against the system. IBM X-Force ID: 199234.
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Analysis
by VulDB Data Team • 10/01/2021
The vulnerability identified as CVE-2021-20563 affects IBM Sterling File Gateway versions ranging from 2.2.0.0 through 6.1.0.3, representing a significant information disclosure weakness that could be exploited by remote authenticated users. This flaw specifically manifests when a malicious actor with valid credentials sends a specially crafted request to the system, resulting in the exposure of valid file paths on the underlying server infrastructure. The vulnerability falls under the category of information disclosure attacks as defined by CWE-200, where sensitive system information is inadvertently revealed to unauthorized parties. The IBM X-Force ID 199234 associated with this vulnerability confirms its recognition within the cybersecurity community and indicates the potential severity of the issue.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient access controls within the file gateway's request processing mechanism. When an authenticated user submits a crafted request, the system fails to properly sanitize or validate the input parameters, allowing the server to respond with directory traversal information or file path details that should remain confidential. This type of vulnerability aligns with ATT&CK technique T1083, which covers the discovery of file and directory permissions, and represents a classic case of path traversal or directory traversal vulnerability that can be leveraged to understand the underlying system structure. The flaw essentially creates an information leak channel that provides attackers with knowledge of the server's file system hierarchy, potentially exposing sensitive directories, configuration files, or other system resources.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked file paths can serve as a foundation for more sophisticated attacks. An attacker who gains knowledge of valid file paths can subsequently attempt directory traversal attacks, file inclusion exploits, or other techniques that rely on understanding the target system's file structure. This information can be particularly valuable when combined with other vulnerabilities or attack vectors, as it provides attackers with precise locations to target for further exploitation. The vulnerability affects the confidentiality aspect of the CIA triad by potentially exposing sensitive system information that could aid in privilege escalation, lateral movement, or other malicious activities within the network environment.
Organizations utilizing IBM Sterling File Gateway versions within the affected range should prioritize immediate remediation through the application of official IBM security patches or updates. The mitigation strategy should include implementing network segmentation to limit access to the file gateway system, enforcing strict access controls, and monitoring for unusual request patterns that might indicate exploitation attempts. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar information disclosure vulnerabilities within the broader system architecture. The vulnerability demonstrates the critical importance of input validation and proper access control implementation, as highlighted in the OWASP Top Ten and other industry security frameworks, which emphasize that information disclosure vulnerabilities often serve as precursors to more serious security incidents. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor and block suspicious requests that attempt to exploit this type of information disclosure vulnerability.