CVE-2018-6562 in Email Encryption Gateway
Summary
by MITRE
totemomail Encryption Gateway before 6.0_b567 allows remote attackers to obtain sensitive information about user sessions and encryption key material via a JSONP hijacking attack.
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Analysis
by VulDB Data Team • 02/07/2020
The CVE-2018-6562 vulnerability affects the totomail Encryption Gateway version prior to 6.0_b567, presenting a critical security flaw that enables remote attackers to extract sensitive information through JSONP hijacking techniques. This vulnerability specifically targets the gateway's handling of user session data and encryption key material, creating a significant risk for organizations relying on this email encryption solution. The flaw stems from improper implementation of JSONP (JSON with Padding) functionality within the web interface, which inadvertently exposes internal session management details and cryptographic keys to unauthorized parties.
The technical implementation of this vulnerability leverages the inherent weaknesses in JSONP mechanisms where cross-domain requests are permitted without proper validation or sanitization of response data. When legitimate users interact with the encryption gateway interface, the system returns JSONP responses containing session identifiers, user authentication tokens, and potentially encryption keys that are not properly protected from cross-origin access. Attackers can exploit this by crafting malicious web pages that leverage the JSONP endpoints to capture these sensitive data elements from the victim's browser context, effectively enabling session hijacking and decryption of encrypted email communications.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally compromises the security model of the encryption gateway. Once attackers obtain session tokens and encryption keys, they can impersonate legitimate users, decrypt previously encrypted messages, and potentially gain access to sensitive corporate communications. This vulnerability directly violates the principle of least privilege and confidentiality that encryption systems are designed to maintain, as it allows unauthorized access to the very cryptographic material that protects email communications. Organizations using affected versions may experience data breaches, compliance violations, and loss of trust from users who rely on encrypted email services.
Mitigation strategies for CVE-2018-6562 should prioritize immediate software updates to version 6.0_b567 or later, which contain patches addressing the JSONP implementation flaws. Additionally, organizations should implement proper CORS (Cross-Origin Resource Sharing) policies to restrict access to sensitive endpoints, disable JSONP functionality where possible, and conduct thorough security assessments of web applications to identify similar vulnerabilities. Network segmentation and monitoring should be enhanced to detect unusual access patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-346 (Origin Validation Error) and CWE-200 (Information Exposure) categories, and maps to ATT&CK techniques including T1071.004 (Application Layer Protocol: DNS) and T1566 (Phishing) when attackers leverage the compromised session data for further attacks. Security teams should also consider implementing web application firewalls and regular penetration testing to identify and remediate similar cross-domain exposure vulnerabilities in their email infrastructure.