CVE-2014-8611 in iOS
Summary
by MITRE
The __sflush function in fflush.c in stdio in libc in FreeBSD 10.1 and the kernel in Apple iOS before 9 mishandles failures of the write system call, which allows context-dependent attackers to execute arbitrary code or cause a denial of service (heap-based buffer overflow) via a crafted application.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2014-8611 represents a critical heap-based buffer overflow flaw within the standard C library implementation of FreeBSD 10.1 and Apple iOS versions prior to 9. This issue resides in the __sflush function located within the fflush.c file of the stdio library component, making it a fundamental weakness in the system's input/output handling mechanisms. The flaw demonstrates how seemingly routine operations can become vectors for severe security breaches when underlying system calls fail to be properly managed.
The technical implementation of this vulnerability stems from improper error handling within the __sflush function which is responsible for flushing buffered output to the underlying file descriptor. When the write system call fails during this process, the function does not adequately validate or handle the error condition, leading to a scenario where corrupted data structures can be written to heap memory regions. This failure mode creates conditions where attackers can manipulate the program's memory layout to execute arbitrary code or trigger denial of service conditions. The vulnerability is context-dependent because it requires specific conditions to be met for exploitation, including the ability to craft malicious input that will cause the write system call to fail in a predictable manner.
From an operational impact perspective, this vulnerability presents a significant risk to systems running affected versions of FreeBSD and iOS, as it allows remote attackers to potentially gain arbitrary code execution privileges. The heap-based nature of the buffer overflow means that attackers can overwrite critical memory structures, potentially leading to privilege escalation or complete system compromise. The denial of service aspect further compounds the risk, as even unsuccessful exploitation attempts can render applications or system services unavailable, impacting system reliability and availability. The vulnerability affects both user-space applications and kernel-level operations, making it particularly dangerous in mobile and server environments.
The mitigation strategies for CVE-2014-8611 primarily involve updating to patched versions of the affected operating systems and libraries. FreeBSD users should upgrade to versions containing the fixed stdio implementation, while Apple iOS users must update to iOS 9 or later to receive the necessary kernel-level patches. System administrators should also implement monitoring for unusual write system call failures and consider implementing additional input validation mechanisms to reduce the attack surface. This vulnerability aligns with CWE-121, heap-based buffer overflow, and maps to ATT&CK technique T1059 for execution through system commands, demonstrating how improper error handling can create pathways for malicious code execution in system-level components. Organizations should prioritize patch management and vulnerability assessment procedures to prevent exploitation of similar issues in their infrastructure.