CVE-2019-19940 in Centro Grande
Summary
by MITRE
Incorrect input sanitation in text-oriented user interfaces (telnet, ssh) in Swisscom Centro Grande before 6.16.12 allows remote authenticated users to execute arbitrary commands via command injection.
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Analysis
by VulDB Data Team • 03/17/2020
This vulnerability exists in the Swisscom Centro Grande system where text-oriented user interfaces such as telnet and ssh are susceptible to command injection attacks due to inadequate input sanitization. The flaw affects versions prior to 6.16.12 and represents a critical security weakness that could be exploited by remote authenticated users to execute arbitrary commands on the affected system. The vulnerability stems from insufficient validation and sanitization of user inputs within the command processing mechanisms of these network services, creating a pathway for malicious command execution.
The technical implementation of this vulnerability occurs when authenticated users provide specially crafted input through telnet or ssh sessions that bypass normal input validation checks. This allows attackers to inject malicious commands that are then processed by the underlying system shell without proper sanitization. The flaw is particularly dangerous because it leverages existing authenticated sessions, eliminating the need for additional authentication steps and allowing attackers to escalate privileges or execute arbitrary code within the system context. This type of vulnerability is categorized under CWE-77 as "Command Injection" which is a well-documented weakness in software systems where user-supplied data is directly incorporated into command execution without proper validation or sanitization.
The operational impact of this vulnerability is severe and multifaceted. Remote authenticated attackers can potentially gain full system control, execute arbitrary code, access sensitive data, modify system configurations, or perform privilege escalation attacks. The attack surface is broad since it affects both telnet and ssh protocols, which are commonly used for system administration and remote access. This vulnerability can lead to complete system compromise, data breaches, and unauthorized access to critical infrastructure components. The attack can be classified under ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically focusing on the use of shell commands to execute malicious code.
Mitigation strategies for this vulnerability include immediate patching of the affected Swisscom Centro Grande system to version 6.16.12 or later, which contains the necessary input sanitization fixes. Organizations should implement comprehensive input validation mechanisms that filter and sanitize all user inputs before processing, particularly for command-line interfaces. Network segmentation and access controls should be strengthened to limit the number of authenticated users with administrative privileges. Regular security audits and vulnerability assessments should be conducted to identify similar input sanitization weaknesses in other system components. Additionally, implementing monitoring and logging of command execution activities can help detect and respond to potential exploitation attempts. The remediation process should also include disabling unnecessary telnet services in favor of more secure ssh implementations and ensuring that all system interfaces properly validate and sanitize input parameters to prevent similar command injection vulnerabilities from occurring in the future.