CVE-2020-36166

Published Jan 6, 2021

Last updated 2 years ago

Overview

Description
An issue was discovered in Veritas InfoScale 7.x through 7.4.2 on Windows, Storage Foundation through 6.1 on Windows, Storage Foundation HA through 6.1 on Windows, and InfoScale Operations Manager (aka VIOM) Windows Management Server 7.x through 7.4.2. On start-up, it loads the OpenSSL library from \usr\local\ssl. This library attempts to load the \usr\local\ssl\openssl.cnf configuration file, which may not exist. On Windows systems, this path could translate to <drive>:\usr\local\ssl\openssl.cnf, where <drive> could be the default Windows installation drive such as C:\ or the drive where a Veritas product is installed. By default, on Windows systems, users can create directories under any top-level directory. A low privileged user can create a <drive>:\usr\local\ssl\openssl.cnf configuration file to load a malicious OpenSSL engine, resulting in arbitrary code execution as SYSTEM when the service starts. This gives the attacker administrator access on the system, allowing the attacker (by default) to access all data, access all installed applications, etc.
Source
cve@mitre.org
NVD status
Modified

Risk scores

CVSS 3.1

Type
Primary
Base score
8.8
Impact score
6
Exploitability score
2
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Severity
HIGH

CVSS 2.0

Type
Primary
Base score
7.2
Impact score
10
Exploitability score
3.9
Vector string
AV:L/AC:L/Au:N/C:C/I:C/A:C

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

  1. Issue summary: The implementations of AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) mishandle the authentication of AAD (Additional Authenticated Data) with an empty ciphertext allowing a forgery of such messages. Impact summary: An attacker can forge empty messages with arbitrary AAD to the victim's application using these ciphers. AES-SIV (RFC 5297) and AES-GCM-SIV (RFC 8452) are nonce-misuse-resistant AEAD modes: they accept a key, nonce, optional AAD (bytes that are authenticated but not encrypted), and plaintext, and produces ciphertext plus a 16-byte tag. On decrypt, `EVP_DecryptFinal_ex()` is documented to return success only if the tag is verified succesfully. In OpenSSL's provider implementation of these ciphers, the expected tag is computed only when decryption function is invoked with non-empty data. If the caller supplies AAD and then calls `EVP_DecryptFinal_ex()` without invocation of the ciphertext update, which can happen when the received ciphertext length is zero, the tag is never recalculated and still holds its all-zeros value. When AES-GCM-SIV is used, an attacker who sends arbitrary AAD, empty ciphertext, and all-zeros tag passes authentication under any key they do not know, single-shot. When AES-SIV is used, for mounting the attack it's necessary for the application to reuse the decryption context without resetting the key. AES-SIV is implemented since OpenSSL 3.0. AES-GCM-SIV is implemented since OpenSSL 3.2. No protocols implemented in OpenSSL itself (TLS/CMS/PKCS7/HPKE/QUIC) support either AES-GCM-SIV or AES-SIV. To mount an attack, the applications must implement their own protocol and use the EVP interface. Also they must skip the ciphertext update when a message with an empty ciphertext arrives. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as these algorithms are not FIPS approved and the affected code is outside the OpenSSL FIPS module boundary.CVE-2026-45446