CVE-2018-12439 in MatrixSSL
Summary
by MITRE
MatrixSSL through 3.9.5 Open allows a memory-cache side-channel attack on ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover an ECDSA key, the attacker needs access to either the local machine or a different virtual machine on the same physical host.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/19/2020
The vulnerability identified as CVE-2018-12439 represents a critical memory-cache side-channel attack targeting the MatrixSSL library version 3.9.5 and earlier. This flaw exploits the Return Of the Hidden Number Problem (ROHNP) to compromise ECDSA cryptographic keys through cache-based information leakage. The attack vector specifically targets the underlying cryptographic implementation where the memory cache behavior during ECDSA signature operations can reveal sensitive key information. The vulnerability demonstrates how modern cryptographic implementations can be undermined through seemingly benign cache access patterns that expose computational artifacts to attackers with sufficient access privileges.
The technical flaw stems from the implementation of elliptic curve digital signature algorithm (ECDSA) within the MatrixSSL library, where the cryptographic operations exhibit cache timing variations that correlate with the private key bits. This vulnerability operates on the principle that when cryptographic operations are performed on shared hardware resources, the cache behavior during computations can leak information about the secret key. Attackers can exploit this by carefully monitoring cache access patterns and timing variations during signature generation processes. The underlying mechanism aligns with the CWE-310 vulnerability class for cryptographic issues related to side-channel attacks, specifically addressing memory cache side-channel vulnerabilities.
The operational impact of this vulnerability extends beyond simple cryptographic compromise, as it enables attackers to perform sophisticated key recovery attacks that can completely undermine the security of encrypted communications. When an attacker gains access to either the local machine or a co-located virtual machine on the same physical host, they can leverage the shared cache infrastructure to reconstruct the private ECDSA key through statistical analysis of cache access patterns. This vulnerability particularly affects systems where multiple tenants share the same physical hardware, making it a significant concern for cloud computing environments and virtualized infrastructures. The attack requires minimal privileges and can be executed by an attacker with local access or a malicious co-tenant in shared hosting environments.
Mitigation strategies for this vulnerability require immediate library updates to versions that address the cache side-channel implementation issues. Organizations should implement cache isolation techniques and ensure that cryptographic operations are performed in memory environments that prevent cross-tenant cache access. The recommended approach includes upgrading to MatrixSSL versions that incorporate proper cache randomization and memory access pattern obfuscation. Additionally, system administrators should consider implementing virtualization-level protections such as cache partitioning or hardware-based isolation mechanisms. This vulnerability aligns with ATT&CK technique T1059.001 for execution through command and scripting interpreter, and T1566 for initial access through shared resources, emphasizing the need for comprehensive security controls that address both software and hardware-level vulnerabilities in cryptographic implementations.