CVE-2017-15533 in SSL Visibility
Summary
by MITRE
Symantec SSL Visibility (SSLV) 3.8.4FC, 3.10 prior to 3.10.4.1, 3.11, and 3.12 prior to 3.12.2.1 are vulnerable to the Return of the Bleichenbacher Oracle Threat (ROBOT) attack. All affected SSLV versions act as weak oracles according the oracle classification used in the ROBOT research paper. A remote attacker, who has captured a pre-recorded SSL session inspected by SSLV, can establish multiple millions of crafted SSL connections to the target and obtain the session keys required to decrypt the pre-recorded SSL session.
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Analysis
by VulDB Data Team • 02/06/2020
The CVE-2017-15533 vulnerability affects Symantec SSL Visibility (SSLV) appliances across multiple version ranges including 3.8.4FC, 3.10 prior to 3.10.4.1, 3.11, and 3.12 prior to 3.12.2.1. This vulnerability represents a critical implementation flaw in the SSL/TLS protocol handling capabilities of these security appliances. The affected systems act as weak oracles in the context of the Return of the Bleichenbacher Oracle Threat (ROBOT) attack, which is a sophisticated cryptographic attack targeting RSA-based SSL/TLS implementations. The vulnerability stems from improper handling of RSA decryption operations during the SSL handshake process, specifically in how the appliances respond to malformed RSA padding attempts. This weakness allows attackers to exploit the timing and response characteristics of the SSLV appliance to determine the private key components through repeated oracle queries.
The operational impact of this vulnerability is severe as it enables remote attackers to perform a massive scale attack against captured SSL sessions that have been inspected by the vulnerable SSLV appliances. The attack methodology involves establishing millions of crafted SSL connections to the target system through the compromised appliance, leveraging the weak oracle behavior to iteratively recover the session keys necessary for decrypting previously captured SSL traffic. This represents a significant threat to organizations relying on SSLV for SSL/TLS traffic inspection, as it undermines the fundamental security assumptions of encrypted communications. The vulnerability particularly affects environments where SSLV appliances are used to monitor and analyze SSL/TLS traffic for security purposes, creating a paradox where the security tool becomes a vector for compromising the very traffic it is designed to protect.
From a technical perspective, this vulnerability aligns with CWE-310, which covers cryptographic issues related to improper implementation of cryptographic primitives, and more specifically relates to CWE-327, which addresses the use of weak or broken cryptographic algorithms. The attack follows patterns described in the ROBOT research methodology and maps to techniques documented in the ATT&CK framework under T1557.001 for "Adversary-in-the-Middle" attacks. Organizations should implement immediate mitigations including upgrading to patched versions of SSLV software, disabling vulnerable SSL/TLS protocol versions, and implementing additional monitoring for suspicious connection patterns. The remediation process requires careful planning due to the critical nature of SSLV appliances in enterprise security infrastructures, and should include thorough testing of patched versions in controlled environments before widespread deployment to prevent service disruptions while addressing the cryptographic weakness that allows the ROBOT attack to succeed.