CVE-2019-11355 in HDX
Summary
by MITRE
An issue was discovered in Poly (formerly Polycom) HDX 3.1.13. A feature exists that allows the creation of a server / client certificate, or the upload of the user certificate, on the administrator's page. The value received from the user is the factor value of a shell script on the equipment. By entering a special character (such as a single quote) in a CN or other CSR field, one can insert a command into a factor value. A system command can be executed as root.
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Analysis
by VulDB Data Team • 04/13/2024
This vulnerability exists within the Poly HDX 3.1.13 video conferencing system where administrators can manage server and client certificates through a web interface. The flaw stems from insufficient input validation when processing certificate signing requests (CSRs) submitted by users. When administrators enter certificate information including the common name (CN) field or other CSR parameters, the system directly incorporates these values into shell command executions without proper sanitization or escaping. This represents a classic command injection vulnerability that allows attackers to execute arbitrary code with root privileges.
The technical implementation of this vulnerability leverages the insecure handling of user-supplied data within shell contexts. When a malicious user submits a CSR containing special characters such as single quotes, backticks, or semicolons in certificate fields, these characters can be interpreted by the shell as command delimiters or operators. The system constructs shell commands using these unsanitized inputs, creating an environment where attacker-controlled commands can be executed with the highest system privileges. This vulnerability specifically affects the certificate management functionality accessible through the administrator web interface, making it particularly dangerous for systems where administrative access is required to manage security certificates.
The operational impact of this vulnerability is severe as it provides attackers with complete system compromise capabilities. Successful exploitation allows remote code execution as the root user, enabling attackers to gain full administrative control over the device. This includes the ability to modify system configurations, install malicious software, exfiltrate sensitive data, or establish persistent backdoors. The vulnerability is particularly concerning because it does not require authentication to exploit, as the certificate upload functionality is accessible to unauthenticated users who can submit malicious CSRs. This makes it a critical security flaw that could be exploited by attackers to compromise video conferencing infrastructure, potentially affecting enterprise communications and security systems.
Organizations should immediately implement mitigations including applying the latest firmware updates from Poly that address this command injection vulnerability. Network segmentation should be implemented to limit access to the administrative interfaces, and strict firewall rules should be enforced to restrict access to the certificate management ports. Input validation and sanitization should be enhanced across all user-facing interfaces, particularly those involving shell command execution. The system should be configured to use secure coding practices that prevent command injection by properly escaping or quoting user inputs before shell execution. This vulnerability aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and maps to ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should also conduct regular security assessments of their video conferencing infrastructure to identify similar injection vulnerabilities and implement principle of least privilege access controls for administrative functions.