CVE-2008-4233 in iPhone OS
Summary
by MITRE
Safari in Apple iPhone OS 1.0 through 2.1 and iPhone OS for iPod touch 1.1 through 2.1 does not isolate the call-approval dialog from the process of launching new applications, which allows remote attackers to make arbitrary phone calls via a crafted HTML document.
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Analysis
by VulDB Data Team • 08/30/2019
This vulnerability exists in Apple's iPhone OS versions 1.0 through 2.1 and iPod touch OS 1.1 through 2.1 where the call-approval dialog lacks proper process isolation from application launching mechanisms. The flaw stems from insufficient sandboxing controls that allow malicious HTML documents to bypass the normal user confirmation process required for making phone calls. When a user visits a specially crafted webpage, the malicious code can trigger phone calls without requiring explicit user interaction through the standard call approval interface.
The technical implementation of this vulnerability exploits a design flaw in the operating system's inter-process communication model where the call-approval dialog shares the same execution context as web content rendering processes. This architectural weakness enables remote code execution within the context of the phone call functionality, allowing attackers to initiate calls to arbitrary numbers without user consent. The vulnerability operates at the application layer and leverages the browser's ability to execute JavaScript and other scripting languages that can interact with system-level functions.
From an operational impact perspective, this vulnerability represents a significant security risk for mobile device users as it enables unauthorized phone call initiation from remote attackers. The attack vector requires the victim to visit a malicious webpage, making it a client-side exploit that can be delivered through various means including phishing campaigns, compromised websites, or malicious advertisements. The potential for financial loss increases significantly as attackers could initiate premium rate calls or international charges without the user's knowledge, while also enabling social engineering attacks that leverage the phone system for further exploitation.
The vulnerability maps to CWE-284 Access Control Issues and specifically relates to improper privilege management in mobile operating systems. It also aligns with ATT&CK technique T1059 Command and Scripting Interpreter where attackers can execute malicious commands through web-based interfaces. This weakness demonstrates a failure in the principle of least privilege and proper process isolation mechanisms that should prevent web content from directly interacting with system functions requiring user authorization. The issue highlights the importance of maintaining strict separation between user interface elements and system-level operations in mobile security architectures.
Mitigation strategies for this vulnerability include implementing proper process isolation between web rendering components and system call initiation functions, enforcing stricter access controls on system-level operations, and ensuring that user approval dialogs operate in separate execution contexts from web content. Users should be advised to avoid visiting untrusted websites and to keep their operating systems updated with the latest security patches. Apple addressed this issue in subsequent updates by strengthening the isolation mechanisms between the browser and system call functions, implementing more robust sandboxing controls, and ensuring that user confirmation dialogs operate independently of web content execution contexts. Organizations should also consider mobile device management solutions that can enforce security policies and prevent access to potentially malicious websites.