CVE-2017-9333 in OpenWebif
Summary
by MITRE
OpenWebif 1.2.5 allows remote code execution via a URL to the CallOPKG function in the IpkgController class in plugin/controllers/ipkg.py, when the URL refers to an attacker-controlled web site with a Trojan horse package. This has security implications in cases where untrusted users can trigger CallOPKG calls, and these users can enter an arbitrary URL in an input field, even though that input field was only intended for a package name. This threat model may be relevant in the latest versions of third-party products that bundle OpenWebif, i.e., set-top box products. The issue of Trojan horse packages does NOT have security implications in cases where the attacker has full OpenWebif access.
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Analysis
by VulDB Data Team • 12/29/2022
The vulnerability identified as CVE-2017-9333 represents a critical remote code execution flaw within OpenWebif version 1.2.5, specifically targeting the CallOPKG function within the IpkgController class. This vulnerability stems from improper input validation and sanitization mechanisms that fail to properly restrict user-supplied URLs, creating an avenue for malicious actors to inject and execute arbitrary code on affected systems. The flaw exists in the plugin/controllers/ipkg.py file where the system processes package installation requests without adequate verification of the source or content of the URLs provided by users.
The technical implementation of this vulnerability exploits a fundamental design weakness in the input handling process where an input field designated for package names is manipulated to accept full URLs pointing to attacker-controlled web resources. When the system processes these malicious URLs through the CallOPKG function, it downloads and attempts to execute package files from the remote server, effectively allowing remote code execution on the target device. This represents a classic command injection vulnerability that leverages the legitimate package management functionality to execute unauthorized operations.
The operational impact of this vulnerability extends significantly in environments where OpenWebif is embedded within set-top box products and other consumer electronics devices. Attackers can leverage this flaw to gain complete control over affected devices, potentially enabling them to install malware, modify system configurations, or establish persistent backdoors. The threat model becomes particularly concerning when considering that untrusted users might have the ability to trigger CallOPKG calls through web interfaces, making the vulnerability exploitable in scenarios where user input is not properly validated. This is especially problematic in third-party products that bundle OpenWebif, as these devices often lack robust security controls and may be deployed in environments where physical security is not maintained.
From a cybersecurity perspective, this vulnerability maps directly to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python." The vulnerability demonstrates a failure in input validation and privilege separation, creating a path for attackers to escalate their privileges and execute arbitrary commands with the privileges of the affected service. The attack surface is broadened by the fact that this vulnerability can be exploited through web-based interfaces, making it accessible to attackers without requiring physical access to the devices.
Mitigation strategies for CVE-2017-9333 should focus on implementing strict input validation and sanitization mechanisms that prevent URL-based inputs from being processed through the CallOPKG function. Organizations should ensure that all user-supplied inputs are properly validated and that the system enforces strict boundaries between intended package names and potentially malicious URLs. The recommended approach includes implementing whitelisting mechanisms for package names, enforcing proper authentication and authorization controls, and ensuring that package management functions are not accessible to untrusted users. Additionally, network segmentation and access controls should be implemented to limit exposure of affected systems, while regular security updates and patches should be applied to prevent exploitation of this vulnerability in deployed environments.