CVE-2021-1783 in watchOS
Summary
by MITRE • 04/03/2021
An access issue was addressed with improved memory management. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. Processing a maliciously crafted image may lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 04/09/2021
The vulnerability identified as CVE-2021-1783 represents a critical access issue within Apple's operating systems that was resolved through enhanced memory management protocols. This flaw existed in multiple Apple platforms including macOS Big Sur, iOS, iPadOS, watchOS, and tvOS, affecting versions prior to their respective security updates. The vulnerability stems from insufficient memory management controls that could be exploited by malicious actors to gain unauthorized access to system resources. The issue was particularly concerning because it could be triggered through the processing of specially crafted image files, which are commonly encountered in everyday computing environments.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions that can lead to information disclosure and potential code execution. The flaw manifests when the system processes malformed image data that contains memory corruption patterns designed to exploit memory management weaknesses. Attackers could craft malicious image files that, when opened or processed by vulnerable systems, would trigger buffer overflow conditions or memory corruption that could be leveraged for privilege escalation. This type of vulnerability falls under the ATT&CK framework's technique T1059 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary code with elevated privileges. The memory management issue creates a pathway for attackers to bypass standard security controls and gain deeper system access.
The operational impact of CVE-2021-1783 extends beyond simple image processing scenarios, as it represents a potential gateway for broader system compromise across Apple's ecosystem. Devices running affected versions could be vulnerable to remote exploitation when processing image files from untrusted sources, including email attachments, web downloads, or file transfers from compromised systems. The vulnerability's presence in multiple platforms including mobile operating systems like watchOS and tvOS increases the attack surface significantly, as these devices often serve as entry points for network infiltration. Organizations relying on Apple devices for business operations face potential data breaches, system compromise, and unauthorized access to sensitive corporate information. The exploitability of this vulnerability through common image processing operations makes it particularly dangerous in enterprise environments where users regularly interact with various media files from external sources.
The remediation for CVE-2021-1783 required immediate deployment of security updates across all affected Apple platforms, with the specific fixes included in macOS Big Sur 11.2, Security Update 2021-001 for Catalina and Mojave, watchOS 7.3, tvOS 14.4, and iOS 14.4. System administrators should prioritize updating all Apple devices within their environments to prevent exploitation, particularly in high-security or compliance-sensitive environments. Organizations should implement network monitoring to detect potential exploitation attempts and consider deploying endpoint protection solutions that can identify and block malicious image files. The fix addresses the underlying memory management issues by implementing stricter bounds checking and improved memory allocation protocols that prevent the corruption patterns that previously enabled arbitrary code execution. Security teams should conduct vulnerability assessments to confirm all affected devices have been properly updated and monitor for any indicators of compromise that might indicate successful exploitation attempts.