CVE-2017-7003 in watchOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3.2 is affected. macOS before 10.12.5 is affected. tvOS before 10.2.1 is affected. watchOS before 3.2.2 is affected. The issue involves the "CoreText" component. It allows remote attackers to cause a denial of service (application crash) via a crafted file.
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Analysis
by VulDB Data Team • 02/08/2021
The vulnerability identified as CVE-2017-7003 represents a critical denial of service flaw within Apple's CoreText framework that affected multiple operating systems including iOS, macOS, tvOS, and watchOS. This issue stems from improper handling of crafted malicious files within the CoreText component, which is responsible for text rendering and font management across Apple's ecosystem. The vulnerability specifically manifests when the system attempts to process malformed or specially constructed text files that exploit memory management flaws in the text processing pipeline. The affected versions demonstrate a lack of proper input validation and bounds checking mechanisms within the CoreText library, creating an exploitable condition that can be triggered remotely through malicious file delivery.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a specially formatted file that, when processed by the CoreText component, causes memory corruption or buffer overflow conditions. This leads to application crashes or system instability that can be leveraged for denial of service attacks against targeted devices. The flaw operates at the text rendering layer of Apple's operating systems, making it particularly dangerous as it can be triggered through various legitimate text processing scenarios including email attachments, web content, or file sharing operations. The vulnerability is classified as a buffer overflow or memory corruption issue that aligns with CWE-121, which describes conditions where a program writes data past the end of a buffer or before the beginning of a buffer, potentially causing system crashes or unpredictable behavior.
From an operational impact perspective, this vulnerability poses significant risks to Apple device users as it can be exploited remotely without requiring user interaction or authentication. Attackers can craft malicious documents or files that, when opened or processed by affected Apple devices, will cause applications to crash or become unresponsive. This creates a persistent denial of service condition that can affect critical applications such as email clients, web browsers, or document viewers. The vulnerability's impact extends across all affected Apple platforms, making it particularly concerning for enterprise environments where device management and security are paramount. Organizations may experience service disruptions, user productivity losses, and potential security exposure when devices are compromised through this vector.
The recommended mitigation strategy involves immediate deployment of Apple's security updates that address the CoreText vulnerability through proper input validation and memory management improvements. System administrators should prioritize patching affected devices to iOS 10.3.2, macOS 10.12.5, tvOS 10.2.1, and watchOS 3.2.2, as these versions contain the necessary fixes for the memory corruption issues. Additionally, network administrators should implement content filtering measures to block suspicious file types and monitor for potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory safety practices as outlined in the ATT&CK framework's defense evasion techniques, where adversaries may leverage memory corruption vulnerabilities to maintain persistent access or disrupt system operations. Organizations should also consider implementing network segmentation and application whitelisting policies to limit the potential impact of such vulnerabilities in their environments.