CME-401

System-wide Crypto Policy (FUTURE)

Harden Application Unquantified evidence Preventive

Description

Centrally enforce minimum cryptographic standards across all system crypto libraries (OpenSSL, GnuTLS, NSS) and their consumers (OpenSSH, Kerberos, HTTPS, LDAP) via update-crypto-policies. The FUTURE policy disables TLS <1.2, SHA-1 signatures, RSA <3072-bit, all CBC mode ciphers, RC4, and DSA, permitting only AEAD ciphers (AES-GCM, ChaCha20-Poly1305), ECDHE/DHE key exchange, and SHA-256+ signatures. This eliminates the attack surface for protocol downgrade attacks (POODLE, DROWN), cipher suite downgrade attacks (FREAK, Logjam), padding oracle attacks (BEAST, Lucky13), and hash collision attacks against SHA-1. The policy is enforced at the library level — applications linked against system crypto libraries inherit the restrictions without code changes. Applications that use their own crypto implementations (Java's keytool/cacerts, Go's crypto/tls, custom-compiled OpenSSL) are not affected and must be configured separately.

CVSS Vector Impacts

Metric	Transition	Rationale
Attack Complexity (AC)	L → H	Without the FUTURE policy, system libraries offer weak protocols and ciphers (TLS 1.0, CBC mode, RC4, SHA-1) that enable well-tooled downgrade attacks: POODLE forces TLS 1.0 fallback, FREAK/Logjam force export-grade key exchange, and padding oracles exploit CBC mode — all with public exploit tools and low complexity. With FUTURE policy active, weak primitives are removed from the library's supported set entirely — the server cannot negotiate down to a vulnerable configuration because the weak options do not exist in memory. This is enforced at the crypto library level before application code runs, making it deterministic rather than configuration-dependent

CWE Relationships

CWE-327 CWE-326 CWE-757

Verification

Verify system-wide crypto policy is set to FUTURE and weak algorithms are excluded from the effective cipher set

$ update-crypto-policies --show
# Expected: FUTURE

Platform: rhel

$ openssl ciphers -v 'DEFAULT' 2>/dev/null | grep -ciE 'RC4|DES|CBC|NULL'
# Expected: 0

Platform: linux

Remediation

rhel Set system-wide crypto policy to FUTURE via update-crypto-policies


update-crypto-policies --set FUTURE
openssl ciphers -v 'DEFAULT' 2>/dev/null | grep -ciE 'RC4|DES|CBC|NULL'

Applicability (CVE 5.2.0 Schema)

Vendor	Product	CPEs	Platforms	Status
redhat	enterprise_linux	`cpe:2.3:o:redhat:enterprise_linux:8:::::::` `cpe:2.3:o:redhat:enterprise_linux:9:::::::` `cpe:2.3:o:redhat:enterprise_linux:10:::::::*`	All	applicable