CVE-2019-12137 in typora
Summary
by MITRE
Typora 0.9.9.24.6 on macOS allows directory traversal, for execution of arbitrary programs, via a file:/// or ../ substring in a shared note.
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Analysis
by VulDB Data Team • 01/11/2025
The vulnerability identified as CVE-2019-12137 affects Typora version 0.9.9.24.6 on macOS operating systems and represents a critical directory traversal flaw that enables arbitrary code execution through manipulated file paths. This vulnerability specifically manifests when the application processes shared notes containing malicious file:/// or ../ substrings, creating a dangerous attack vector that bypasses normal file system access controls and permissions. The flaw stems from inadequate input validation and path resolution mechanisms within the application's handling of shared note references, allowing attackers to manipulate the file system navigation logic to access and execute arbitrary programs beyond the intended scope of the application's file operations.
The technical exploitation of this vulnerability occurs through the manipulation of file path references in shared notes, where the ../ substring or file:/// protocol handlers can be used to traverse directories and access files outside the application's designated working directory. This directory traversal vulnerability maps directly to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw allows attackers to construct malicious paths that bypass normal file system restrictions, potentially enabling access to sensitive system files, user data, or system resources that should remain protected from unauthorized access. When combined with the shared note functionality, this vulnerability becomes particularly dangerous as it can be exploited through social engineering or by compromising shared documents that are subsequently opened by unsuspecting users.
The operational impact of this vulnerability extends beyond simple unauthorized file access to encompass full system compromise capabilities through arbitrary code execution. Attackers can leverage this flaw to execute malicious programs with the privileges of the user running Typora, potentially leading to complete system compromise, data exfiltration, or further escalation within the network environment. The vulnerability affects macOS users who regularly share notes or documents through Typora, making it particularly concerning for collaborative environments where shared documents are common. The attack surface is broadened by the fact that this vulnerability can be triggered through legitimate note sharing functionality, making it difficult for users to distinguish between safe and malicious content. This vulnerability also aligns with ATT&CK technique T1059.001, which covers command and script interpreter execution, as the arbitrary code execution capability allows attackers to run malicious scripts or programs directly on the compromised system.
Mitigation strategies for CVE-2019-12137 should focus on immediate application updates to versions that address the directory traversal vulnerability, as well as implementing network-level restrictions to prevent access to potentially malicious shared content. Organizations should establish strict policies for handling shared documents and notes, particularly those originating from external sources or untrusted parties. The implementation of input validation controls within the application's file path handling logic is essential, ensuring that all file references are properly sanitized and validated before processing. Security monitoring should include detection of suspicious file path patterns and unauthorized access attempts to sensitive system resources. System administrators should also consider implementing application whitelisting policies that restrict the execution of arbitrary programs and maintain regular security updates to prevent exploitation of similar vulnerabilities. Additionally, user education regarding the risks of opening shared documents from untrusted sources is crucial in reducing the likelihood of successful exploitation through social engineering tactics that leverage this vulnerability.