CVE-2017-9807 in OpenWebif Plugin
Summary
by MITRE
An issue was discovered in the OpenWebif plugin through 1.2.4 for E2 open devices. The saveConfig function of "plugin/controllers/models/config.py" performs an eval() call on the contents of the "key" HTTP GET parameter. This allows an unauthenticated remote attacker to execute arbitrary Python code or OS commands via api/saveconfig.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-9807 represents a critical remote code execution flaw within the OpenWebif plugin version 1.2.4 and earlier for E2 open devices. This security weakness resides in the plugin's configuration handling mechanism where the saveConfig function in plugin/controllers/models/config.py directly processes user-supplied input through an eval() operation. The flaw occurs when the system accepts the "key" parameter from HTTP GET requests without proper sanitization or validation, creating an attack vector that allows unauthenticated remote exploitation.
The technical implementation of this vulnerability stems from the dangerous use of Python's eval() function which interprets and executes arbitrary code passed as strings. When an attacker crafts a malicious HTTP GET request containing specially formatted data in the key parameter, the eval() function processes this input as Python code rather than treating it as simple data. This fundamental flaw in input validation and code execution flow violates core security principles and creates a pathway for complete system compromise. The vulnerability is categorized under CWE-94, which specifically addresses the execution of arbitrary code due to improper input validation, and aligns with ATT&CK technique T1059.006 for command and script injection.
The operational impact of CVE-2017-9807 extends far beyond simple data manipulation as it provides attackers with complete control over affected E2 open devices. An unauthenticated remote attacker can leverage this vulnerability to execute arbitrary Python code, which may include system commands that could lead to privilege escalation, data exfiltration, or complete system takeover. The implications are particularly severe for set-top boxes and media center devices that rely on such web interfaces, as these systems often have access to sensitive user data, network configurations, and potentially connected IoT devices. The vulnerability essentially transforms a legitimate web interface into a backdoor for malicious actors to gain persistent access to the underlying system.
Mitigation strategies for CVE-2017-9807 require immediate action to address the root cause of the vulnerability. The most effective solution involves removing or replacing the eval() call with safe input validation and processing mechanisms that properly sanitize all user-supplied data. Organizations should implement proper parameter validation and avoid dynamic code execution unless absolutely necessary. Additionally, the affected OpenWebif plugin versions should be updated to the latest releases that contain patched implementations. Network segmentation and firewall rules can provide temporary protection by restricting access to the vulnerable web interface, while monitoring systems should be deployed to detect suspicious HTTP GET requests containing potentially malicious payloads. The remediation process must also include thorough code review to identify and eliminate similar patterns of unsafe code execution that may exist elsewhere in the application's codebase.