CVE-2012-3732 in iOS
Summary
by MITRE
Mail in Apple iOS before 6 uses an S/MIME message s From address as the displayed sender address, which allows remote attackers to spoof signed content via an e-mail message in which the From field does not match the signer s identity.
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Analysis
by VulDB Data Team • 04/13/2021
The vulnerability described in CVE-2012-3732 represents a critical security flaw in Apple iOS email handling mechanisms that specifically affects versions prior to iOS 6. This issue resides in the S/MIME email signature verification process where the system fails to properly validate the authenticity of email senders, creating a significant vector for social engineering attacks and email spoofing operations. The flaw operates at the cryptographic validation layer of email security, where the system should verify that the sender address in the email header matches the identity embedded within the S/MIME signature but instead relies on the potentially manipulated From field.
The technical implementation of this vulnerability stems from how iOS processes S/MIME signed emails and validates the sender identity. When an email arrives with an S/MIME signature, the system should cross-reference the signer's identity from the digital certificate against the email's From address to ensure authenticity. However, in affected iOS versions, the system incorrectly displays the From address from the email header rather than verifying the actual signer identity from the S/MIME signature. This creates a scenario where attackers can craft malicious emails with forged From addresses that appear legitimate to users, even though they contain valid S/MIME signatures from different entities.
The operational impact of this vulnerability extends beyond simple email spoofing to encompass broader security implications for enterprise email systems and user trust mechanisms. Attackers can exploit this weakness to create convincing phishing campaigns where signed emails appear to originate from trusted sources such as company executives, financial institutions, or government agencies. This vulnerability directly relates to CWE-347, which addresses the weakness of improper certificate validation, and aligns with ATT&CK technique T1566.001 for spearphishing through email. The flaw essentially undermines the fundamental security promise of S/MIME email signatures, which are designed to provide authentication and integrity verification for email communications.
Organizations and users affected by this vulnerability face significant risks including unauthorized access to sensitive information, financial fraud, and compromise of corporate email systems. The vulnerability enables attackers to bypass traditional email security measures that rely on S/MIME signatures as a means of verifying sender authenticity. Mitigation strategies should include immediate upgrade to iOS 6 or later versions where Apple addressed the issue through improved S/MIME signature validation mechanisms. Additionally, organizations should implement additional email security controls such as domain-based message authentication, reporting, and conformance (DMARC) policies, email encryption solutions, and user education programs to reduce the effectiveness of such spoofing attacks. The vulnerability also highlights the importance of proper cryptographic validation procedures and demonstrates how seemingly minor implementation flaws can create substantial security risks in email authentication systems.