CVE-2019-9150 in Mailvelope
Summary
by MITRE
Mailvelope prior to 3.3.0 does not require user interaction to import public keys shown on web page. This functionality can be tricked to either hide a key import from the user or obscure which key was imported.
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Analysis
by VulDB Data Team • 10/24/2023
The vulnerability described in CVE-2019-9150 affects Mailvelope versions prior to 3.3.0, representing a significant security flaw in the browser extension's key management system. This issue stems from insufficient user interaction requirements during the public key import process, creating a potential attack vector that undermines the security model of end-to-end encrypted communications. The vulnerability allows malicious actors to manipulate the key import mechanism in ways that either conceal the import action from users or obscure the identity of the imported key, thereby compromising the integrity of the user's key management environment.
The technical implementation flaw resides in the extension's failure to enforce mandatory user confirmation steps when public keys are encountered on web pages. This design weakness enables automated key import processes that bypass normal user awareness protocols. According to CWE-602, this represents a client-side input validation issue where the application relies on potentially untrusted data without proper verification. The vulnerability specifically targets the trust model of PGP-based encryption systems where users must explicitly approve key additions to maintain control over their cryptographic identity. When users are not prompted for confirmation, they cannot verify the legitimacy of imported keys, potentially allowing attackers to inject malicious keys that could compromise encrypted communications.
The operational impact of this vulnerability extends beyond simple user inconvenience to represent a serious threat to communication security. Attackers can exploit this flaw by crafting web pages that automatically import malicious public keys without user awareness, potentially enabling man-in-the-middle attacks or key substitution scenarios. The ability to hide key imports from users creates a stealthy attack vector where compromised communications can go unnoticed for extended periods. This vulnerability directly impacts the security posture of users relying on Mailvelope for encrypted email communications, as it undermines the fundamental principle that users must actively approve cryptographic key changes. The attack surface is particularly concerning in phishing scenarios where malicious websites could silently import compromised keys that would then be used to intercept or manipulate encrypted messages.
From a mitigation perspective, the primary solution involves updating to Mailvelope version 3.3.0 or later, which implements proper user interaction requirements for key imports. Organizations should also consider implementing additional security measures such as key pinning, regular key verification procedures, and user education about the importance of confirming key imports. The vulnerability aligns with ATT&CK technique T1556.001, which covers credential access through credential dumping and key manipulation. Security teams should monitor for potential exploitation attempts and implement network-level detection measures to identify suspicious key import patterns. Regular security assessments of browser extensions and cryptographic tools should be conducted to identify similar vulnerabilities that might compromise user security. The incident underscores the critical importance of maintaining up-to-date security software and the necessity of user interaction requirements in cryptographic applications to prevent unauthorized key manipulation.