CVE-2011-3257 in iOS
Summary
by MITRE
The Data Access component in Apple iOS before 5 does not properly handle the existence of multiple user accounts on the same mail server, which allows local users to bypass intended access restrictions in opportunistic circumstances by leveraging a different account s cookie.
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Analysis
by VulDB Data Team • 11/24/2021
The vulnerability described in CVE-2011-3257 represents a critical access control flaw within Apple iOS versions prior to 5.0, specifically affecting the Data Access component responsible for managing email account authentication and session handling. This issue stems from insufficient validation mechanisms that fail to properly distinguish between multiple user accounts sharing the same mail server infrastructure, creating a fundamental security gap in the operating system's authentication framework. The flaw operates at the session management level where the system does not adequately enforce account separation when cookies are utilized for authentication purposes, allowing malicious actors to exploit this weakness for unauthorized access.
The technical implementation of this vulnerability resides in how iOS handles cookie persistence and authentication state management across multiple email accounts. When multiple users authenticate to the same mail server, the system fails to properly isolate the authentication cookies associated with each account, enabling a local attacker to potentially leverage credentials from one account to access another account's data. This occurs because the Data Access component does not implement proper session boundary enforcement, which is a core requirement for maintaining account isolation in multi-user environments. The vulnerability essentially allows for privilege escalation through session hijacking techniques where an attacker can manipulate the cookie-based authentication state to gain access to unauthorized email data.
The operational impact of this vulnerability extends beyond simple unauthorized data access, as it fundamentally undermines the security model of iOS email handling and creates opportunities for data exfiltration and privacy violations. Local users who have access to a device with multiple email accounts configured can exploit this weakness to read, modify, or delete email messages from other accounts without proper authentication. This represents a significant breach of the principle of least privilege and demonstrates a failure in implementing proper access controls as defined by security standards such as those outlined in the CWE-284 category for improper access control. The vulnerability is particularly concerning in enterprise environments where multiple user accounts may exist on the same device, creating a potential attack surface for insider threats or compromised accounts.
Mitigation strategies for CVE-2011-3257 require immediate system updates to iOS version 5.0 or later, which includes the necessary patches to properly handle multi-account scenarios and implement correct cookie isolation mechanisms. Organizations should also consider implementing additional monitoring for unusual authentication patterns and session behavior that might indicate exploitation attempts. The vulnerability aligns with ATT&CK techniques related to credential access and privilege escalation, particularly those involving session management and authentication bypass. Security teams should also review their email security policies and ensure that proper account separation measures are implemented at the network level, including server-side configurations that prevent the sharing of authentication contexts between different user accounts. Regular security assessments should verify that authentication mechanisms properly enforce account boundaries and that no similar session management flaws exist in other components of the system architecture.