CVE-2014-4366 in iOS
Summary
by MITRE
Mail in Apple iOS before 8 does not prevent sending a LOGIN command to a LOGINDISABLED IMAP server, which allows remote attackers to obtain sensitive cleartext information by sniffing the network.
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Analysis
by VulDB Data Team • 02/20/2022
The vulnerability described in CVE-2014-4366 represents a critical security flaw in Apple iOS mail handling mechanisms that persisted across versions prior to iOS 8. This issue specifically affects the Internet Message Access Protocol (IMAP) implementation within the mobile operating system's email client. The flaw occurs when the system fails to properly enforce server-side authentication restrictions, creating an avenue for malicious actors to exploit cleartext credential transmission during email authentication processes. The vulnerability stems from inadequate protocol compliance and security enforcement within the iOS mail application's IMAP client implementation.
The technical root cause of this vulnerability lies in the improper handling of IMAP server responses, particularly those indicating that login operations are disabled or restricted. When an IMAP server responds with a LOGINDISABLED status, legitimate mail clients should cease attempting authentication operations and avoid transmitting any authentication credentials. However, the affected iOS versions failed to respect this server directive, continuing to send LOGIN commands even when explicitly disabled by the server. This behavior exposes cleartext username and password information to network sniffing attacks, as the authentication credentials are transmitted without encryption or proper security controls. The flaw essentially creates a bypass mechanism that allows attackers to circumvent server-side security configurations that should prevent unauthorized authentication attempts.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables attackers to gain unauthorized access to email accounts through man-in-the-middle attacks or network eavesdropping. Security researchers have classified this issue under CWE-312, which deals with cleartext storage of sensitive information, and CWE-287, addressing improper authentication mechanisms. The vulnerability aligns with ATT&CK technique T1566, which covers credential harvesting through phishing and network sniffing attacks, and T1071, focusing on application layer protocols for command and control communications. Attackers exploiting this vulnerability can intercept unencrypted authentication traffic passing through public networks, wireless access points, or compromised network segments, potentially gaining access to sensitive corporate or personal email accounts. The impact is particularly severe in environments where users access email services over untrusted networks, such as public wifi hotspots, making this vulnerability a significant concern for mobile email security.
Organizations and individual users should implement immediate mitigations including updating to iOS 8 or later versions where this vulnerability is resolved, ensuring all email communications utilize encrypted connections through STARTTLS or SSL/TLS protocols, and implementing network monitoring to detect unusual authentication patterns. System administrators should enforce security policies requiring encrypted email access and consider deploying network segmentation to limit exposure to untrusted network segments. The fix implemented in iOS 8 addresses the core issue by properly enforcing server-side login restrictions and preventing the transmission of cleartext credentials when authentication is disabled by the server. Additionally, users should be educated about the risks of accessing email services over unencrypted networks and the importance of maintaining up-to-date mobile device software to protect against known vulnerabilities. Security teams should monitor for potential exploitation attempts and implement network intrusion detection systems capable of identifying suspicious authentication patterns that may indicate exploitation of this vulnerability.