CVE-2020-9920 in watchOS
Summary
by MITRE • 10/23/2020
A path handling issue was addressed with improved validation. This issue is fixed in iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6, watchOS 6.2.8. A malicious mail server may overwrite arbitrary mail files.
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Analysis
by VulDB Data Team • 10/04/2022
The vulnerability identified as CVE-2020-9920 represents a path traversal flaw that affects Apple's mail handling systems across multiple operating systems including iOS, iPadOS, macOS, and watchOS. This issue stems from inadequate validation of file paths during mail processing operations, creating a potential attack vector where malicious actors can manipulate file system access through crafted mail server responses. The vulnerability specifically impacts the way mail clients handle file paths when processing incoming messages, particularly those containing attachments or references to external resources.
The technical implementation of this flaw allows an attacker to exploit improper input validation in the mail processing pipeline by sending specially crafted mail messages from a malicious server. When the affected mail client processes these messages, it fails to properly sanitize or validate file paths that may be embedded within the mail content or attachments. This validation failure enables an attacker to manipulate the file system operations and potentially overwrite arbitrary mail files on the target device. The vulnerability operates at the application layer and leverages the trust relationship between the mail client and mail servers, making it particularly dangerous in environments where users receive mail from untrusted sources.
The operational impact of CVE-2020-9920 extends beyond simple file overwrites to potentially compromise the integrity of user mail data and system security. Attackers could use this vulnerability to overwrite critical mail files, corrupt user data, or potentially execute malicious code through carefully crafted mail content. The vulnerability affects multiple Apple platforms, increasing its potential attack surface and making it particularly concerning for enterprise environments where users may be accessing corporate mail systems. The issue also represents a significant concern for users who may inadvertently receive malicious mail from compromised servers or phishing campaigns.
Apple addressed this vulnerability through comprehensive input validation improvements in their mail processing components. The fix involves enhanced path validation mechanisms that properly sanitize file paths before any file system operations are performed. This remediation aligns with established security practices for preventing path traversal attacks and follows industry standards for input validation as outlined in CWE-22. The security update specifically targets the mail handling components in iOS 13.6, iPadOS 13.6, macOS Catalina 10.15.6, and watchOS 6.2.8, requiring users to update to these versions to mitigate the risk. Organizations should prioritize deployment of these security updates as part of their vulnerability management processes, particularly given the potential for remote exploitation through mail servers. The fix demonstrates Apple's approach to addressing application-level security issues through improved input validation and proper resource handling as recommended in ATT&CK framework techniques related to privilege escalation and persistence through file system manipulation.