CVE-2019-6803 in typora
Summary
by MITRE
typora through 0.9.9.20.3 beta has XSS, with resultant remote command execution, via the left outline bar.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 07/03/2023
The vulnerability identified as CVE-2019-6803 affects typora versions through 0.9.9.20.3 beta and represents a significant security flaw that combines cross-site scripting with potential remote command execution capabilities. This vulnerability specifically resides within the left outline bar functionality of the markdown editor application, making it particularly dangerous as it targets a core user interface element that is frequently interacted with during normal document editing operations. The flaw allows attackers to inject malicious scripts that can execute within the context of the user's browser session, potentially leading to complete system compromise.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the outline bar component. When users view documents with maliciously crafted content, the application fails to properly escape or filter user-provided data before rendering it in the outline sidebar. This creates an environment where attacker-controlled scripts can be executed with the privileges of the logged-in user, effectively bypassing traditional security boundaries. The vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and more specifically with CWE-94 which addresses arbitrary code execution vulnerabilities that can result from insufficient input sanitization. The attack vector is particularly concerning because it leverages the application's legitimate rendering functionality to deliver malicious payloads.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable full system compromise. An attacker who successfully exploits this vulnerability could gain access to the victim's file system, execute arbitrary commands, and potentially escalate privileges. The outline bar serves as a persistent interface element that users frequently interact with while editing documents, making the attack surface particularly broad and the exploitation likelihood high. This vulnerability could be exploited through various means including malicious markdown files shared via email, collaboration platforms, or compromised websites that serve typora documents. The combination of XSS and RCE capabilities means that attackers can establish persistent backdoors, exfiltrate sensitive data, or use the compromised system as a launch point for further attacks within the network.
Mitigation strategies for CVE-2019-6803 should prioritize immediate software updates to versions that have addressed this vulnerability. Users should also implement defensive measures including disabling the outline bar functionality when viewing untrusted documents, employing content filtering solutions, and maintaining strict access controls for markdown files. Organizations should consider implementing application whitelisting policies that restrict execution of typora from untrusted sources. Additionally, security awareness training should emphasize the dangers of opening documents from unknown or untrusted sources, as the vulnerability can be exploited through social engineering attacks that deliver malicious markdown content. The ATT&CK framework categorizes this type of vulnerability under T1059 which describes command and script injection techniques, and T1071 which addresses application layer protocols, highlighting the multi-faceted nature of the threat. Regular security assessments and penetration testing should include verification of proper input sanitization in all user interface components, particularly those that render dynamic content.