CVE-2020-9988 in iOS
Summary
by MITRE • 12/09/2020
The issue was addressed with improved deletion. This issue is fixed in macOS Big Sur 11.0.1, iOS 14.0 and iPadOS 14.0. A local user may be able to discover a user’s deleted messages.
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Analysis
by VulDB Data Team • 12/15/2020
The vulnerability identified as CVE-2020-9988 represents a significant privacy flaw in Apple's messaging ecosystem that persisted across multiple operating system versions. This issue specifically affected the handling of deleted messages within the Messages application, creating a potential exposure where sensitive communications could remain accessible to local users even after deletion. The flaw existed in macOS versions prior to Big Sur 11.0.1 and iOS 14.0, indicating a widespread impact across Apple's mobile and desktop platforms. The vulnerability stems from inadequate memory management and data sanitization processes that failed to completely eliminate deleted message content from system storage, leaving residual data accessible through various forensic and recovery techniques.
The technical nature of this vulnerability aligns with CWE-200, which addresses information exposure through improper handling of deleted data, and represents a classic case of insecure deletion practices within mobile operating systems. When users deleted messages from their conversation history, the underlying system did not properly overwrite or securely erase the associated data blocks, creating a window of opportunity for unauthorized access. This flaw operates at the file system level where deleted messages might still exist in unallocated space, temporary memory areas, or cached data structures that persist beyond the normal deletion process. The vulnerability demonstrates how seemingly simple operations like message deletion can create complex security implications when proper data sanitization procedures are not implemented.
From an operational perspective, this vulnerability poses significant risks to user privacy and could enable adversaries to access sensitive information contained within deleted conversations. The local user access requirement means that an attacker would need physical access to the device or administrative privileges, but the implications remain severe given that deleted messages often contain personal communications, financial information, or confidential business data. The impact extends beyond individual privacy concerns to potential corporate security breaches where employees might inadvertently expose sensitive information through deleted conversations. This vulnerability particularly affects environments where mobile devices contain classified information or where users handle highly sensitive communications that should not persist in any form after deletion.
The mitigation strategy for CVE-2020-9988 primarily involves updating to the patched versions of macOS Big Sur 11.0.1 and iOS 14.0, which implemented improved deletion mechanisms that properly sanitize message data from system memory and storage. Organizations should prioritize deployment of these updates across all affected devices and consider implementing additional security measures such as full disk encryption and secure deletion policies for sensitive data. Security teams should also conduct vulnerability assessments to identify any remaining instances of the vulnerable software and ensure that proper incident response procedures are in place to address potential exploitation attempts. The fix demonstrates Apple's approach to addressing information exposure vulnerabilities through enhanced data sanitization processes that align with security best practices outlined in frameworks such as NIST SP 800-53 for secure data handling and disposal.