CVE-2015-3774 in Mac OS X
Summary
by MITRE
The Dictionary app in Apple OS X before 10.10.5 does not use HTTPS, which allows man-in-the-middle attackers to obtain sensitive information by sniffing the network or spoof word definitions by modifying the client-server data stream.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability identified as CVE-2015-3774 represents a significant security weakness in Apple's Dictionary application affecting macOS versions prior to 10.10.5. This flaw resides in the application's failure to implement secure communication protocols when fetching dictionary definitions from remote servers. The absence of HTTPS encryption creates a dangerous attack surface that exposes users to multiple threat vectors. The Dictionary app typically retrieves word definitions from online sources to provide comprehensive linguistic information, but without proper encryption, this communication channel becomes vulnerable to various network-based attacks. This vulnerability directly violates fundamental security principles of data confidentiality and integrity, as outlined in the CWE-319 category for cleartext transmission of sensitive information.
The technical implementation flaw stems from the Dictionary app's reliance on unencrypted HTTP connections for all dictionary lookups. When users search for words, the application establishes connections to remote servers using HTTP rather than the secure HTTPS protocol. This design decision creates opportunities for attackers positioned within the network path to intercept and manipulate the communication between the client and server. Network sniffing attacks can capture the plaintext dictionary data being transmitted, potentially exposing users to information disclosure attacks. Additionally, attackers can perform man-in-the-middle operations to modify the returned word definitions, injecting false information or malicious content directly into the user's dictionary experience. The vulnerability demonstrates a classic case of insufficient cryptographic protection in network communications, which falls under the ATT&CK technique of T1071.1001 for application layer protocol: web protocols.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential malicious manipulation of user data. Attackers can exploit this weakness to inject false definitions into dictionary searches, potentially spreading misinformation or conducting social engineering attacks through seemingly legitimate dictionary content. The vulnerability affects all users of affected macOS versions, making it a widespread concern across Apple's user base. Given that dictionary applications are commonly used and trusted by users, the attack surface is particularly concerning as users may not question the legitimacy of altered definitions. The lack of encryption in the communication channel means that even network administrators or compromised network nodes can observe and modify dictionary queries and responses. This vulnerability represents a failure in the principle of least privilege and secure by design, as the application does not implement proper security controls to protect sensitive user data. Organizations using affected systems face potential risks of data manipulation and information compromise, particularly in environments where network security is not adequately enforced. The vulnerability's remediation requires updating to macOS 10.10.5 or later, which implements proper HTTPS encryption for dictionary lookups, thereby addressing both the confidentiality and integrity concerns associated with this flaw.