CVE-2008-4593 in iPhone
Summary
by MITRE
Apple iPhone 2.1 with firmware 5F136, when Require Passcode is enabled and Show SMS Preview is disabled, allows physically proximate attackers to obtain sensitive information by performing an Emergency Call tap and then reading SMS messages on the device screen, aka Apple bug number 6267416.
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Analysis
by VulDB Data Team • 10/11/2018
This vulnerability exists in Apple iPhone 2.1 firmware version 5F136 and represents a significant security flaw in the device's passcode protection mechanism. The issue arises from a specific interaction between two security settings that creates an unexpected information disclosure channel. When users enable the Require Passcode feature while simultaneously disabling the Show SMS Preview option, the device fails to properly enforce its security boundaries during emergency call scenarios.
The technical flaw manifests through a physical proximity attack vector where an attacker can exploit the emergency call functionality to bypass the passcode protection. During an emergency call, the device allows immediate access to SMS messages without requiring the passcode verification that should normally be enforced. This creates a window of opportunity for attackers to read sensitive information from the device screen, despite the passcode being enabled for general device protection. The vulnerability specifically affects devices where the Show SMS Preview setting is disabled, which typically should prevent unauthorized access to message content.
The operational impact of this vulnerability is substantial as it undermines the fundamental security model of mobile device passcode protection. Attackers can exploit this weakness without requiring sophisticated technical skills or specialized equipment, making it particularly dangerous in environments where physical access to devices is possible. The vulnerability essentially creates a backdoor that allows unauthorized information disclosure even when the device appears to be properly secured. This affects not only individual users but also organizations that rely on mobile devices for sensitive communications, as it could lead to data breaches and privacy violations.
This vulnerability maps to CWE-200 (Information Exposure) and CWE-287 (Improper Authentication) within the CWE taxonomy, demonstrating how inadequate security controls can lead to information disclosure. From an ATT&CK perspective, this represents a technique under T1552 (Unsecured Credentials) and T1059 (Command and Scripting Interpreter) where attackers exploit device-specific security flaws to access sensitive information. The vulnerability also aligns with T1566 (Phishing) as it represents an attack vector that requires minimal user interaction beyond physical proximity. Organizations should implement comprehensive security policies that address such device-specific vulnerabilities and ensure that all security settings are properly configured to prevent unauthorized access to sensitive information.
Mitigation strategies should include immediate firmware updates to address the specific bug number 6267416, proper security configuration management, and comprehensive user education about the risks associated with device security settings. Security teams should also implement device management policies that enforce proper security configurations and conduct regular security assessments to identify similar vulnerabilities in mobile device ecosystems. The incident highlights the importance of thorough security testing during device development and the need for robust security controls that consider all possible attack vectors, including those that exploit seemingly minor configuration interactions between different security features.