CVE-2018-4227 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. The issue involves the "Mail" component. It allows remote attackers to read the cleartext content of S/MIME encrypted messages via direct exfiltration.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/25/2024
The vulnerability identified as CVE-2018-4227 represents a critical security flaw within Apple's Mail application affecting multiple operating systems including iOS versions prior to 11.4 and macOS versions prior to 10.13.5. This weakness specifically targets the S/MIME encryption implementation within the Mail component, creating a significant risk for users who rely on encrypted email communication for sensitive data protection. The vulnerability stems from improper handling of encrypted message content during the decryption process, allowing malicious actors to bypass intended security measures.
The technical nature of this flaw enables remote attackers to perform direct exfiltration of cleartext content from S/MIME encrypted messages without requiring authentication or access to the underlying encryption keys. This represents a fundamental breakdown in the cryptographic protection mechanism, as the vulnerability allows attackers to intercept and read the actual message content even when it was intended to be protected by S/MIME encryption. The flaw operates at the application layer and specifically exploits how the Mail application processes and displays decrypted content, creating a pathway for unauthorized data access.
From an operational perspective, this vulnerability poses severe implications for organizations and individuals who depend on secure email communication channels. The ability to read cleartext content from S/MIME encrypted messages undermines the core purpose of S/MIME encryption, which is designed to protect sensitive information from unauthorized access during transmission. This weakness affects the confidentiality aspect of the CIA triad, potentially exposing confidential business communications, personal data, or proprietary information that was supposed to remain protected. The remote nature of the attack means that threat actors can exploit this vulnerability from anywhere on the internet without requiring physical access to the target system.
The vulnerability aligns with CWE-200, which addresses "Information Exposure," and demonstrates how improper implementation of cryptographic functions can lead to information leakage. From an ATT&CK framework perspective, this weakness maps to techniques involving credential access and data exfiltration, specifically targeting the mail client as a vector for information compromise. Organizations should consider this vulnerability as part of broader email security assessments, particularly when evaluating the effectiveness of S/MIME encryption implementations. The flaw represents a failure in proper cryptographic implementation and validation, where the system should have prevented access to decrypted content until proper authentication and verification processes were completed.
Mitigation strategies should prioritize immediate system updates to the affected Apple operating system versions, ensuring that all devices receive the necessary security patches. Organizations should also consider implementing additional email security measures such as secure email gateways, enhanced monitoring of email traffic, and regular security assessments of email client configurations. Network administrators should monitor for potential exploitation attempts and implement network-based detection measures to identify unusual traffic patterns associated with data exfiltration activities. Additionally, users should be educated about the risks of opening suspicious emails and the importance of maintaining updated software versions to protect against known vulnerabilities.