CVE-2017-7086 in tvOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11 is affected. macOS before 10.13 is affected. tvOS before 11 is affected. watchOS before 4 is affected. The issue involves the "libc" component. It allows remote attackers to cause a denial of service (resource consumption) via a crafted string that is mishandled by the glob function.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/20/2021
The vulnerability identified as CVE-2017-7086 represents a critical resource consumption flaw within Apple's operating systems affecting multiple platforms including iOS, macOS, tvOS, and watchOS. This security issue resides within the libc component, which serves as a fundamental system library providing essential functions for program execution and system operations. The flaw specifically targets the glob function implementation, which is responsible for pattern matching and file name expansion commonly used in shell operations and system utilities. The vulnerability manifests when the system processes crafted strings that are improperly handled by the glob function, leading to excessive resource consumption that can ultimately result in system instability or complete denial of service conditions.
The technical exploitation of this vulnerability occurs through the manipulation of string inputs that are passed to the glob function within the libc library. When a malicious actor crafts a specific string pattern, the glob function fails to properly validate or process the input, causing it to enter into resource-intensive operations that consume excessive memory and CPU cycles. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-400, which covers resource exhaustion vulnerabilities. The improper handling of input parameters in the glob function creates a scenario where the system's resource management becomes compromised, allowing attackers to consume system resources at an unsustainable rate. The vulnerability is particularly concerning because it operates at the system library level, making it accessible to various application contexts and potentially exploitable through multiple attack vectors.
The operational impact of CVE-2017-7086 extends across all affected Apple platforms, creating widespread potential for denial of service attacks that can disrupt normal system operations and user experiences. In iOS environments, this vulnerability could enable attackers to crash applications or cause the entire operating system to become unresponsive, particularly when applications rely on glob pattern matching for file operations or shell command execution. The macOS impact is equally significant, as the vulnerability could affect system stability during routine operations involving file system navigation and pattern matching. On tvOS and watchOS platforms, the resource consumption could lead to complete device unresponsiveness, affecting user experience and potentially enabling more sophisticated attacks. The vulnerability's potential for remote exploitation means that attackers could trigger the denial of service conditions without requiring physical access to the device, making it particularly dangerous in enterprise and consumer environments.
Mitigation strategies for CVE-2017-7086 focus primarily on applying the official security updates provided by Apple, which include patches to the libc library and related system components. Organizations should prioritize immediate deployment of iOS 11, macOS 10.13, tvOS 11, and watchOS 4 updates to address the vulnerability. System administrators should also implement network monitoring to detect unusual resource consumption patterns that might indicate exploitation attempts. Additionally, application developers should review their code for potential reliance on glob functions and implement proper input validation to prevent malicious string patterns from reaching the vulnerable system libraries. The remediation process should include comprehensive testing to ensure that the patches do not introduce compatibility issues with existing applications. Security teams should also consider implementing access controls and monitoring for system resources to detect and respond to potential exploitation attempts. This vulnerability demonstrates the importance of maintaining up-to-date system libraries and highlights the need for robust input validation practices across all system components, aligning with ATT&CK technique T1499 for resource exhaustion attacks and emphasizing the critical nature of system library security.