CVE-2017-17845 in Enigmail
Summary
by MITRE
An issue was discovered in Enigmail before 1.9.9. Improper Random Secret Generation occurs because Math.Random() is used by pretty Easy privacy (pEp), aka TBE-01-001.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-17845 represents a critical cryptographic weakness in the Enigmail email encryption plugin for Mozilla Thunderbird. This flaw stems from the improper implementation of random number generation within the pretty Easy privacy pEp framework, which is integrated into Enigmail's cryptographic operations. The vulnerability specifically manifests when the system relies on JavaScript's Math.random() function for generating cryptographic secrets, which fundamentally undermines the security guarantees that cryptographic systems require for proper operation.
The technical flaw arises from the use of pseudo-random number generators that lack sufficient entropy and cryptographic strength. Math.random() in JavaScript produces numbers that are not cryptographically secure and can be predictable, especially when the underlying implementation is not designed for cryptographic purposes. This weakness allows attackers to potentially predict or reproduce the secret keys used in the encryption process, thereby compromising the confidentiality and integrity of encrypted communications. The vulnerability falls under the broader category of weak random number generation, which is classified as CWE-330 in the Common Weakness Enumeration system, specifically addressing insufficient entropy in random number generation.
The operational impact of this vulnerability extends beyond simple data exposure, as it fundamentally compromises the trust model that users place in encrypted email communications. Attackers who can predict or guess the cryptographic secrets generated by the flawed implementation can decrypt sensitive emails, impersonate users, or perform man-in-the-middle attacks against encrypted communications. This weakness directly affects the confidentiality and authenticity guarantees that cryptographic systems are designed to provide, making it particularly dangerous for organizations that rely on email encryption for protecting sensitive information. The vulnerability represents a significant deviation from established security practices and violates the principles outlined in the NIST SP 800-90A standard for random number generation.
Mitigation strategies for this vulnerability require immediate updates to the Enigmail plugin to version 1.9.9 or later, which addresses the random number generation issue by implementing proper cryptographic random number generators. System administrators should also consider implementing additional security measures such as monitoring for unusual cryptographic key generation patterns and ensuring that all email encryption systems use properly validated cryptographic libraries. The fix implemented in the updated version ensures that cryptographic operations utilize cryptographically secure random number generators that meet industry standards and prevent the predictable patterns that attackers could exploit to compromise encrypted communications. Organizations should also review their overall email security posture and consider implementing additional layers of protection such as multi-factor authentication and secure key management practices to further mitigate the risk of cryptographic compromise.