CVE-2017-0379 in Communications WebRTC Session Controller
Summary
by MITRE
Libgcrypt before 1.8.1 does not properly consider Curve25519 side-channel attacks, which makes it easier for attackers to discover a secret key, related to cipher/ecc.c and mpi/ec.c.
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Analysis
by VulDB Data Team • 06/27/2023
The vulnerability identified as CVE-2017-0379 affects Libgcrypt versions prior to 1.8.1 and represents a critical weakness in the cryptographic implementation of Curve25519 elliptic curve operations. This flaw specifically targets the side-channel attack resistance mechanisms that should protect against timing and power analysis attacks. The vulnerability resides in the cipher/ecc.c and mpi/ec.c source files, which handle elliptic curve cryptography operations including the Curve25519 implementation. These files contain insufficient protections against side-channel information leakage that could reveal sensitive cryptographic keys.
The technical nature of this vulnerability stems from inadequate constant-time implementation of elliptic curve scalar multiplication operations. When Libgcrypt processes Curve25519 operations, it fails to properly mask the computational patterns that would otherwise allow attackers to infer information about the secret key through careful analysis of timing variations or power consumption patterns. This weakness aligns with CWE-388, which addresses the improper handling of side-channel information, and represents a failure to implement proper constant-time cryptographic algorithms that are essential for protecting against differential power analysis and timing attacks. The vulnerability specifically impacts the implementation of elliptic curve operations where the computational steps vary based on the bits of the secret scalar, creating observable patterns that attackers can exploit.
The operational impact of this vulnerability is significant for systems relying on Libgcrypt for secure communications, digital signatures, and key exchange operations. Attackers who can observe or manipulate the timing characteristics of cryptographic operations may be able to recover private keys used in Curve25519 implementations, potentially compromising the security of encrypted communications, digital signatures, and authentication protocols. This vulnerability affects any application using Libgcrypt versions before 1.8.1 for Curve25519 operations, including SSH implementations, TLS connections, and various cryptographic libraries that depend on Libgcrypt for their elliptic curve functionality. The attack vector typically involves passive observation of timing characteristics or active manipulation of execution environment to induce measurable differences in computational timing.
Mitigation strategies for CVE-2017-0379 require immediate upgrading to Libgcrypt version 1.8.1 or later, which contains proper constant-time implementations of Curve25519 operations. Organizations should conduct comprehensive inventory assessments to identify all systems and applications using vulnerable Libgcrypt versions, particularly those implementing Curve25519 for cryptographic operations. The remediation process should include not only updating the library but also verifying that applications properly handle the updated cryptographic implementations and retesting security configurations. Additionally, system administrators should implement monitoring for any unusual timing patterns or potential side-channel attack indicators. This vulnerability demonstrates the critical importance of proper side-channel resistance in cryptographic implementations and aligns with ATT&CK technique T1059.001 for command and script interpreter usage, as attackers may leverage compromised keys to execute further malicious activities. Organizations should also consider implementing additional cryptographic protections such as key rotation procedures and enhanced monitoring for potential exploitation attempts.