CVE-2018-4106 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.4 is affected. The issue involves the Bracketed Paste Mode of the "Terminal" component. It allows user-assisted attackers to inject arbitrary commands within pasted content.
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Analysis
by VulDB Data Team • 07/27/2024
The vulnerability identified as CVE-2018-4106 represents a significant security flaw in Apple's macOS operating system affecting versions prior to 10.13.4. This issue specifically targets the Terminal application's handling of bracketed paste mode, a feature designed to distinguish between regular text input and paste operations. The flaw arises from insufficient validation of pasted content when bracketed paste mode is enabled, creating a potential attack vector that could be exploited by malicious actors. The vulnerability falls under the category of command injection, where an attacker can manipulate terminal behavior through crafted input sequences. This type of vulnerability is particularly concerning in security contexts where terminal applications are used for administrative tasks, system management, or development work where command execution privileges are elevated.
The technical implementation of this vulnerability stems from how the Terminal application processes bracketed paste mode sequences. When bracketed paste mode is active, the terminal sends specific escape sequences to indicate when text is being pasted versus typed manually. However, the implementation fails to properly sanitize or validate the content that follows these paste indicators, allowing attackers to inject malicious commands within what appears to be normal pasted text. The flaw operates on the principle of improper input validation and inadequate sanitization of user-supplied data, which are classic patterns identified in CWE-20 and CWE-74 categories. Attackers can craft specially formatted paste operations that, when executed in a vulnerable terminal session, result in arbitrary command execution within the context of the user's privileges.
The operational impact of CVE-2018-4106 extends beyond simple command injection, as it can enable attackers to perform a wide range of malicious activities within compromised terminal sessions. An attacker with access to a user's terminal session could potentially execute commands with the same privileges as the user, potentially leading to privilege escalation scenarios or system compromise. The vulnerability is particularly dangerous in environments where users frequently paste code snippets, configuration data, or other text from untrusted sources into terminal applications. This attack vector aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries leverage legitimate system tools to execute malicious code. The user-assisted nature of this vulnerability means that the attack requires some form of user interaction, typically involving the user pasting malicious content into a terminal session, making it a social engineering component that can be combined with other attack vectors.
Mitigation strategies for CVE-2018-4106 primarily focus on updating affected systems to macOS 10.13.4 or later versions where Apple has implemented proper input validation for bracketed paste mode. System administrators should ensure all terminal sessions are updated and that users are educated about the risks of pasting content from untrusted sources. Additional protective measures include disabling bracketed paste mode in terminal applications when working with untrusted content, implementing network-level controls to monitor for suspicious terminal activity, and maintaining regular security updates across all systems. Organizations should also consider implementing security monitoring solutions that can detect anomalous command execution patterns in terminal sessions, as this vulnerability could be used in conjunction with other attack techniques to establish persistent access to compromised systems. The remediation approach should align with security best practices outlined in NIST SP 800-128 for terminal security and general system hardening guidelines.