CVE-2016-4670 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.1 is affected. macOS before 10.12.1 is affected. The issue involves the "Security" component. It allows local users to discover lengths of arbitrary passwords by reading a log.
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Analysis
by VulDB Data Team • 05/17/2019
The vulnerability identified as CVE-2016-4670 represents a significant information disclosure flaw within Apple's security architecture affecting multiple operating systems. This weakness resides in the security component of iOS versions prior to 10.1 and macOS versions prior to 10.12.1, creating a pathway for malicious actors to potentially compromise system integrity through indirect means. The flaw specifically enables local users to determine the lengths of arbitrary passwords by examining system log files, which represents a serious degradation of security controls designed to protect sensitive authentication data.
The technical nature of this vulnerability stems from improper handling of password length information within system logging mechanisms. When authentication attempts occur on affected systems, the security component generates log entries that inadvertently expose password length characteristics. This occurs because the logging subsystem does not adequately sanitize or obscure sensitive information during the recording process, allowing unauthorized local access to discover password length patterns. The flaw operates at the kernel level or system services that handle authentication events, making it particularly concerning as it affects core security infrastructure rather than application-level components.
The operational impact of CVE-2016-4670 extends beyond simple information disclosure, as password length information can significantly aid attackers in subsequent exploitation phases. An attacker who discovers that a target system uses passwords of specific lengths can optimize brute force or dictionary attack strategies, potentially reducing the computational resources required to compromise accounts. This vulnerability aligns with CWE-200, which addresses "Information Exposure," and represents a classic example of how seemingly innocuous logging practices can create security weaknesses. The issue also maps to ATT&CK technique T1083, which covers "File and Directory Discovery," as it enables adversaries to gather information about system authentication mechanisms through log file examination.
Mitigation strategies for this vulnerability require immediate system updates to the patched versions of iOS 10.1 and macOS 10.12.1, which address the root cause by implementing proper log sanitization procedures. Organizations should also implement additional monitoring of system logs for unusual access patterns and consider implementing more restrictive access controls for log files. The vulnerability demonstrates the importance of comprehensive security testing that includes evaluation of logging and auditing mechanisms, as these components often serve as attack vectors when not properly secured. System administrators should conduct thorough vulnerability assessments to ensure all affected devices have been updated and should monitor for potential exploitation attempts that might leverage this information disclosure.